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Patient participation in the decision to treat coronary artery disease 1986

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PATIENT PARTICIPATION IN THE DECISION TO TREAT CORONARY ARTERY DISEASE By MARIAN JANE FULTON B.H.Ec. (honours), The U n i v e r s i t y of B r i t i s h Columbia, 1969 P r o f e s s i o n a l C e r t i f i c a t e i n Education, The U n i v e r s i t y of B r i t i s h Columbia, 1979 M.Sc, The U n i v e r s i t y of B r i t i s h Columbia, 1982 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS OF THE DEGREE OF DOCTOR OF PHILOSOPHY IN THE FACULTY OF GRADUATE STUDIES The Department of I n t e r d i s c i p l i n a r y S t u d i e s We accept t h i s t h e s i s as sronforming to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA August 1986 (g) Marian Jane F u l t o n , 1986 or- In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of I n t e r d i s c i p l i n a r y Studies The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 DE-6(3/81) i i ABSTRACT T h i s study was based on the normative argument t h a t p a t i e n t s ought to p a r t i c i p a t e i n treatment d e c i s i o n s t h a t c o u l d i n f l u e n c e the l e n g t h and q u a l i t y of t h e i r l i v e s . E f f o r t s were made to e x p l o r e p o t e n t i a l e r r o r s of judgement t h a t c o u l d i n t e r f e r e w i t h the e x p r e s s i o n of a t r u e p r e f e r e n c e by a p a t i e n t . The r e s u l t s of t h i s e x p l o r a t i o n suggested t h a t people i n r e a l d e c i s i o n making s i t u a t i o n s a re a f f e c t e d by fra m i n g , they make i n c o n s i s t e n t c h o i c e s , they r e v e r s e p r e f e r e n c e s i n s i t u a t i o n s where p r e f e r e n c e s are expressed by b i d s versus c h o i c e s , and t h e i r c h o i c e s change i n s i t u a t i o n s of p o t e n t i a l g a i n and p o t e n t i a l l o s s . P a r t i c i p a n t s i n the study were w i l l i n g to pay f o r an improved p o s i t i o n on a w a i t i n g l i s t f o r treatment, but they were ve r y r e l u c t a n t to s e l l or t r a d e such a p o s i t i o n . An a n a l y s i s of p a t i e n t s ' age and exposure to the h e a l t h system demonstrated t h a t age was not a p r e d i c t o r of p a t i e n t c h o i c e s w h i l e p a i n and d i s a b i l i t y were c o n t r i b u t i n g f a c t o r s to p a t t e r n s of c h o i c e . G e n e r a l l y , p a t i e n t p r e f e r e n c e s were s i t u a t i o n s p e c i f i c . Recommendations have been made f o r improving p r o f e s s i o n a l s e n s i t i v i t y towards p a t i e n t s whose s i t u a t i o n makes them more v u l n e r a b l e to e r r o r s of judgement. F u r t h e r avenues f o r r e s e a r c h have been s k e t c h e d . ACKNOWLEDGEMENTS I would l i k e to acknowledge, above a l l o t h e r s , Dr. Vance F. M i t c h e l l . As Chairman of my t h e s i s committee and of my program, Dr. M i t c h e l l o f f e r e d the guidance, s u p p o r t , and c o n s t r u c t i v e c r i t i c i s m t h a t made an I n t e r d i s c i p l i n a r y Program p o s s i b l e . I am a l s o indebted to Dr. C h a r l e s R. Kerr and Dr. M a r t i n T. Schechter who, as members of the t h e s i s committee p r o v i d e d d i r e c t i o n f o r the r e s e a r c h and a n a l y s i s d e s c r i b e d i n t h i s s t udy. I am g r a t e f u l to Dr. Henry M i z g a l a , Head, D i v i s i o n of C a r d i o l o g y , Vancouver Gen e r a l H o s p i t a l , and Dr. Derek Gellman, V i c e - P r e s i d e n t and D i r e c t o r of Research a t the Vancouver General H o s p i t a l , who reviewed the p r o p o s a l f o r the study and granted p e r m i s s i o n f o r p a t i e n t s to be i n t e r v i e w e d a t the h o s p i t a l . Dr. K e r r , a l o n g with Dr. M i z g a l a , Dr. V i c t o r H u c k e l l , and Dr. Don R i c c i , allowed t h e i r p a t i e n t s to p a r t i c i p a t e i n t h i s s t u dy. The enthusiasm and c o - o p e r a t i o n of these p h y s i c i a n s and t h e i r p a t i e n t s was an important f a c t o r i n the success of t h i s endeavour. I would l i k e to thank Dr. D a n i e l Kahneraan and Dr. K. R. MacCrimmon f o r r e v i e w i n g the q u e s t i o n n a i r e and making v a l u a b l e comments. I a l s o a p p r e c i a t e d the e a r l i e r remarks of Dr. Ri c h a r d T h a l e r from C o r n e l l U n i v e r s i t y and Dr. Jack Knetsch from Simon F r a s e r U n i v e r s i t y . Others o f f e r i n g welcome s u g g e s t i o n s f o r i v improving the a n a l y s i s of the data and s t r u c t u r e of the r e p o r t were Dr. Shelby Brumelle, Dr. W.T. Stanbury and Roch Payayre. I would a l s o l i k e to thank the p h y s i c i a n s who allowed me to observe p a t i e n t p a r t i c i p a t i o n i n r e a l treatment d e c i s i o n s under emergency c o n d i t i o n s . I am g r a t e f u l t o : Dr. Max W a l t e r s , Dr. C h a r l e s K e r r , Dr. V i c t o r i a B e r n s t e i n , Dr. M i c h a e l Moscovich, Dr. Tom P e r r y , J r . , and Dr. Adam Waldie . The S o c i a l S c i e n c e s and Humanities Research C o u n c i l of Canada has supported t h i s r e s e a r c h p r o j e c t through t h e i r D o c t o r a l F e l l o w s h i p Program. I would l i k e to express my g r a t i t u d e to them f o r t h e i r c o n t i n u e d c o n f i d e n c e . F i n a l l y , I would l i k e to say thank you to my p a r e n t s , Dr. B l a i r F u l t o n and Margaret F u l t o n f o r t h e i r encouragement; and to my daughters, Jean, Amy, Sarah and L i l a who were p a t i e n t and l o v i n g throughout. V TABLE OF CONTENTS T i t l e Page i A b s t r a c t i i Acknowledgements i i i CHAPTER 1 SECTION ONE: PATIENT PREFERENCES: the R a t i o n a l e 1.0 I n t r o d u c t i o n 1 1.1 Three Models of M e d i c a l Care 4 1.2 Informed Consent 9 1.3 A t t r i b u t e s of M e d i c a l D e c i s i o n Making 12 1.4 U n c e r t a i n t y i n C l i n i c a l M e d i c i ne: a Component of R i sk 16 1.5 Re p r e s e n t i n g Risk i n Med i c a l D e c i s i o n Making 17 1.6 Summary 23 SECTION TWO: CORONARY HEART DISEASE: H i s t o r y , Epidemiology, and Economics 2.0 The C l i n i c a l H i s t o r y of Coronary Heart D i s e a s e 25 2.1 Grading the Angina of Coronary Heart Disease 27 2.2 The Epidemiology of Coronary Heart D i s e a s e 28 2.3 The P r o g r e s s i v e Nature of Coronary Heart D i s e a s e 31 2.4 The C l i n i c a l Background: M e d i c a l Therapy 32 2.5 The C l i n i c a l Background: Coronary Bypass Surgery 34 2.6 The C l i n i c a l Background: A n g i o p l a s t y 38 v i 2.7 The Cost of M e d i c a l Therapy i n Canada 40 2.8 The Cost of Coronary A r t e r y Bypass G r a f t i n g 41 2.9 The Cost of A n g i o p l a s t y 43 2.10 C o n c l u s i o n s from the C l i n i c a l D i s c u s s i o n 44 2.11 The Research Questions 47 CHAPTER 2 MEASURING PATIENT PREFERENCES: Methodology I. 0 I n t r o d u c t i o n 50 2.0 S t r u c t u r e of the Chapter 51 3.0 Sampling S t r a t e g y 51 4.0 P a i n as a F a c t o r i n D e c i s i o n Making 56 5.0 I n t r o d u c i n g S u b j e c t s to the Q u e s t i o n n a i r e 56 6.0 The S u b j e c t ' s Role 59 7.0 I n t e r v i e w e r B i a s 61 8.0 P a t i e n t Assurance 62 9.0 A t t r i b u t e s of P a t i e n t Choice 64 10.0 Measuring U t i l i t y i n the Heart Study 66 I I . 0 Measurement S t r a t e g i e s 68 11.1 Standard Gamble and Comparisons 69 11.2 Ranking and,Preference S c a l i n g 73 11.3 Time-Trade-Off 74 12.0 A d m i n i s t e r i n g the Q u e s t i o n n a i r e 74 13.0 The Use of P a t i e n t P r e f e r e n c e s Over Time 76 14.0 S t a t i s t i c a l A n a l y s i s 77 15.0 C o n c l u s i o n s 78 v i i CHAPTER 3 THE STUDY OF PATIENT PREFERENCES: E r r o r s of Judgement 1.0 I n t r o d u c t i o n 80 2.0 The C e r t a i n t y E f f e c t : an Example of R i s k A v e r s i o n 81 2.1 R e s u l t s of C e r t a i n t y E f f e c t Q u estions 85 3.0 P r e f e r e n c e R e v e r s a l 85 3.1 R e s u l t s of P r e f e r e n c e R e v e r s a l 90 3.2 D i s c u s s i o n of P r e f e r e n c e R e v e r s a l 91 4.0 Framing: the F o r m u l a t i o n E f f e c t 93 4.1 Framing E f f e c t s 96 4.2 D i s c u s s i o n of Framing - 98 4.3 D i s c u s s i o n of D i a g n o s t i c Groups 98 4.4 C o n c l u s i o n s 99 5.0 The S u b s t i t u t i o n E f f e c t 100 5.1 D i s c u s s i o n 103 6.0 Asymmetric C h o i c e : Choices i n the Domain of Gains or Losses 106 6.1 D i s c u s s i o n 110 6.2 C o n c l u s i o n s 112 7.0 W i l l i n g n e s s - t o - P a y 113 7.1 R e s u l t s of W i l l i n g n e s s - t o - P a y 118 7.2 D i s c u s s i o n 118 7.3 C o n c l u s i o n s 119 8.0 The Endowment E f f e c t 119 8.1 R e s u l t s of Endowment E f f e c t Q u estions 120 V I 11 8.2 C o n c l u s i o n s 123 9.0 Summary of F i n d i n g s 124 CHAPTER 4 MEDICAL DECISION MAKING: P a t i e n t P r e f e r e n c e s , Demographic C h a r a c t e r i s t i c s , and Q u a l i t y of L i f e Issues 1.0 I n t r o d u c t i o n 125 2.0 Investment i n Future H e a l t h 126 2.1 D i s c u s s i o n 130 2.2 C o n c l u s i o n s - 131 3.0 Value of R i s k Avoidance 131 3.1 R e s u l t s and D i s c u s s i o n 134 3.2 A n a l y s i s of U t i l i t y Curves f o r Risk A v e r s i o n 142 4.0 P r e f e r e n c e s f o r M o r b i d i t y w i t h No Risk 143 4.1 R e s u l t s and D i s c u s s i o n 144 5.0 P a t i e n t Age as an Independent V a r i a b l e 145 5.1 V u l n e r a b i l i t y to the I n f l u e n c e of Framing 146 6.0 P r e v i o u s H e a l t h E x p e r i e n c e as an Independent V a r i a b l e 146 6.1 R e s u l t s and D i s c u s s i o n 148 7.0 The I n f l u e n c e of Coronary A r t e r y Bypass on C h o i c e s 149 8.0 H e a l t h E x p e r i e n c e and Risk Avoidance 150 8.1 R e s u l t s and D i s c u s s i o n 151 i x 9.0 H e a l t h E x p e r i e n c e and Choice of S u r g i c a l Treatment 153 10.0 Summary 155 11.0 L i m i t a t i o n s of the Study 156 12.0 C o n c l u s i o n s 160 13.0 O p p o r t u n i t i e s f o r Fu t u r e Research 161 14.0 F i n a l Comments 162 APPENDIX I C e r t i f i c a t e from the U n i v e r s i t y of B r i t i s h Columbia E t h i c s Committee 164 L e t t e r of P e r m i s s i o n from Dr. Henry M i z g a l a 165 L e t t e r of I n t r o d u c t i o n to S u b j e c t s and P a t i e n t s 166 Consent Form 167 The Q u e s t i o n n a i r e 168 APPENDIX II V i s u a l A i d s 177 BIBLIOGRAPHY 190 X LIST OF TABLES 1.1. Grading of Angina of E f f o r t by the Canadian C a r d i o v a s c u l a r S o c i e t y 28 1.2. H o s p i t a l Stays f o r Canadians w i t h Heart D i s e a s e , 1978 ' 30 1.3. H o s p i t a l Stays f o r Canadians w i t h Heart D i s e a s e , 1980-81 31 1.4. Average Cost of A n t i a n g i n a l Drugs i n Canada 41 1.5. Summary of Treatments and Outcomes i n the D e c i s i o n to T r e a t Coronary A r t e r y D i s e a s e 45 3.1. P r e f e r e n c e R e v e r s a l f o r A l l S u b j e c t s 91 3.2. Framing E f f e c t s f o r A l l Heart Study S u b j e c t s 97 3.3. S u b s t i t u t i o n P r i n c i p l e : A l l Respondents 103 3.4. S u b s t i t u t i o n P r i n c i p l e : Heart Disease Groups 104 3.5. S u b s t i t u t i o n P r i n c i p l e : H e a l t h y S u b j e c t s and H o s p i t a l A d m i n i s t r a t o r s 104 3.6. Asymmetric Choice f o r A l l P a t i e n t s 110 3.7. Asymmetric Choice f o r A l l H e a l t h y S u b j e c t s 110 3.8. W i l l i n g n e s s to Pay f o r A l l P a t i e n t s and H e a l t h y S u b j e c t s 118 3.9. Compensation Demanded 121 4.1. Investment i n Future H e a l t h by P a t i e n t Groups 128 4.2. Value of A v o i d i n g L i f e R i s k 134 4.3. Risk A v e r s i o n Scores of D i a g n o s t i c Groups 142 x i 4.4. M y o c a r d i a l I n f a r c t i o n and W a i t i n g Choices 148 4.5. The I n f l u e n c e of Coronary A r t e r y Bypass on W a i t i n g 149 4.6. H e a l t h E x p e r i e n c e and Risk Avoidance 151 4.7. Angina P a i n and R i s k y Choice 153 4.8. D i a g n o s i s as an Independent V a r i a b l e 155 LIST OF FIGURES 4.1. Investment i n F u t u r e H e a l t h 128 4.2. Risk A v e r s i o n i n Heart Study Groups 136 4.3. U t i l i t y of R i s k A v e r s i o n f o r Healthy S u b j e c t s 137 4.4. U t i l i t y of Risk A v e r s i o n f o r Heart D i s e a s e C o n t r o l s 138 4.5. U t i l i t y of Risk A v e r s i o n f o r P a t i e n t s w i t h M i l d Angina 139 4.6. U t i l i t y of R i s k A v e r s i o n f o r P a t i e n t s w i t h Severe Angina 140 1 CHAPTER 1 PATIENT PREFERENCES: The R a t i o n a l e 1.0 I n t r o d u c t i o n The p r e s e n t study was an e x p l o r a t i o n of p a t i e n t p a r t i c i p a - t i o n i n the c h o i c e of a treatment f o r c o r o n a r y a r t e r y d i s e a s e . I t s emphasis was on two q u e s t i o n s . F i r s t , what c o n t r i b u t i o n to m e d i c a l d e c i s i o n making can be made by b e t t e r knowledge of p a t i e n t p r e f e r e n c e s ? And, second, how do p o t e n t i a l e r r o r s i n e x p r e s s i n g those p r e f e r e n c e s i n f l u e n c e c h o i c e s ? To answer these q u e s t i o n s , the study i n v o l v e d p a t i e n t s with h e a r t d i s e a s e who made c h o i c e s under s i m u l a t e d c o n d i t i o n s . F i r s t , p a t i e n t s i n d i c a t e d the v a l u e of r e d u c t i o n s o f : r i s k , m o r b i d i t y , and w a i t i n g time. Second, q u e s t i o n s were posed to e v a l u a t e the d i r e c t i o n and s t r e n g t h of s e v e r a l p o t e n t i a l e r r o r s of judgement p r e v i o u s l y i d e n t i f i e d and developed by o t h e r s , i n some cases i n f i e l d s o ther than h e a l t h c a r e . Treatment c h o i c e s f o r p a t i e n t s with c o r o n a r y heart d i s e a s e were chosen f o r a number of reasons. F i r s t , h e a r t d i s e a s e i s the l e a d i n g cause of death i n Canada, and h o s p i t a l treatment f o r h e a r t d i s e a s e i s a major consumer of r e s o u r c e s i n the h e a l t h care system. Second, cor o n a r y h e a r t d i s e a s e causes more long-term d i s a b i l i t y , and economic l o s s due to time away from p r o d u c t i v e a c t i v i t y than any other group of d i s e a s e s i n the i n d u s t r i a l i z e d n a t i o n s of the world (Braunwald, 1984) . I t has been e s t i m a t e d 2 t h a t each year 200,000 Americans under the age of 65 d i e from coronary h e a r t d i s e a s e and an a d d i t i o n a l 2,000,000 people are a f f l i c t e d w i t h i t . T r e a t i n g t h i s d i s e a s e and compensating f o r the l o s s of p r o d u c t i v i t y i t causes i s e s t i m a t e d to c o s t the American n a t i o n $50 b i l l i o n each year (Braunwald, 1984). I f the c o s t of t r e a t i n g coronary h e a r t d i s e a s e i n Canada i s roug h l y e s t i m a t e d to be one-tenth of t h a t i n the U n i t e d S t a t e s , an annual b i l l of f i v e b i l l i o n d o l l a r s i s s i g n i f i c a n t . Q u i t e a p a r t from the d o l l a r c o s t of t h i s d i s e a s e , the l o s s of human l i f e and d i s a b i l i t y i t causes i s a c o m p e l l i n g reason f o r e x p l o r i n g the p o s s i b i l i t y of improving m e d i c a l d e c i s i o n making f o r p a t i e n t s w i t h coronary h e a r t d i s e a s e . A t h i r d important reason f o r s t u d y i n g a c t u a l medical d e c i s i o n s i n t r e a t i n g heart d i s e a s e i s t h a t the treatments f o r t h i s d i s e a s e c a r r y r i s k s f o r the p a t i e n t , as does non-treatment. C u r r e n t trends i n h e a l t h c a r e , such as the p a t i e n t ' s r i g h t s movement, i n d i c a t e t h a t g r e a t e r p a r t i c i p a t i o n i n treatment c h o i c e s i s being demanded by p a t i e n t s . Moreover, c r i t i c s of the t r a d i t i o n a l approach to d e c i s i o n making by p h y s i c i a n s are promoting a normative argument t h a t p a t i e n t s 'ought' to p a r t i c i - pate i n the d e c i s i o n s t h a t so o b v i o u s l y a f f e c t t h e i r l i v e s . The p r e s e n t study f o l l o w s the p r o t o c o l suggested by Keeney (1982). F i r s t , a d i s c u s s i o n i s p r e s e n t e d of r e s e a r c h t h a t d e s c r i b e s the l i k e l i h o o d s of the p o s s i b l e outcomes of each treatment a l t e r n a t i v e f o r c o r o n a r y h e a r t d i s e a s e . Randomized, 3 c o n t r o l l e d t r i a l s o f f e r the bes t e p i d e m i o l o g i c a l evidence of outcome d i f f e r e n c e s , and such s t u d i e s are reviewed. Second, the method f o r e l i c i t i n g p a t i e n t p r e f e r e n c e s i s d e s c r i b e d . T h i r d , key s t u d i e s o f p a t i e n t p r e f e r e n c e s and common e r r o r s of human judgement are reviewed to p r o v i d e a f o u n d a t i o n f o r the q u e s t i o n s posed to p a t i e n t s . F i n a l l y , the f i n d i n g s of the study are re p o r t e d and c o n c l u s i o n s a re drawn. The remainder of t h i s c hapter p r o v i d e s the background f o r the study of treatment p r e f e r e n c e s of p a t i e n t s with c o r o n a r y h e a r t d i s e a s e 1. F i r s t , the i s s u e of p a t i e n t p a r t i c i p a t i o n i s addressed as i t i s e v o l v i n g i n m e d i c a l d e c i s i o n making. A d i s c u s s i o n of t r a d i t i o n a l p h y s i c i a n - p a t i e n t i n t e r a c t i o n , autonomy, and informed consent i l l u s t r a t e c u r r e n t a t t i t u d e s toward p a t i e n t p a r t i c i p a t i o n , w h i l e a b r i e f review of r i s k , u n c e r t a i n t y , and the s t r u c t u r e of d e c i s i o n t r e e s i n medical d e c i s i o n making d e s c r i b e the nature of the d e c i s i o n s p h y s i c i a n s and p a t i e n t s make. T h i s d i s c u s s i o n p r o v i d e s the r a t i o n a l e f o r e l i c i t i n g p a t i e n t v a l u e s f o r the a l t e r n a t i v e treatments and h e a l t h outcomes t h a t a f f e c t p a t i e n t s . The a l t e r n a t i v e treatments and the p r o b a b i l i - t i e s of l o s s e s and b e n e f i t s , t o g e t h e r with p a t i e n t v a l u e s , generate the key items of the t o o l of medi c a l d e c i s i o n making - the d e c i s i o n t r e e . The c l i n i c a l h i s t o r y of coronary h e a r t 1 Coronary h e a r t d i s e a s e i s a l s o c a l l e d c o r o n a r y a r t e r y d i s e a s e and coro n a r y a t h e r o s c l e r o s i s . These terms are used i n t e r c h a n g e a b l y i n the l i t e r a t u r e . 4 d i s e a s e , i t s epidemiology, and economics i n the Canadian s e t t i n g are then examined. 1.2. Three Models of M e d i c a l Care Three models of medical care r e l e v a n t to p h y s i c i a n and p a t i e n t i n t e r a c t i o n can be i d e n t i f i e d i n the l i t e r a t u r e . The f i r s t i s the p a s s i v e p a t i e n t model where the p h y s i c i a n a c t s and the p a t i e n t i s ac t e d upon. In t h i s model, ' t h e r a p e u t i c p r i v i - l e g e ' a l l o w s the p h y s i c i a n the moral leeway to " s e t a s i d e the normal duty of d i s c l o s u r e " (Harron e t . a l . , 1983, p. 90). Support f o r t h i s model comes from Barber (1980, p. 16) who s t a t e s : "We valu e f u l l d i s c l o s u r e , so t h a t the ... p a t i e n t can make a reasoned and prudent d e c i s i o n f o r h i m s e l f ; but we a l s o v a l u e the humane p r o t e c t i o n of those who are somehow weak or i n e p t - the young, the f r i g h t e n e d , the d y i n g . " Some argue t h a t r e v e a l i n g the g r a v i t y of an i l l n e s s to a p a t i e n t may a c t u a l l y harm the p a t i e n t . The counter argument s t a t e s t h a t l i t t l e c l i n i c a l e v i d e n c e supports t h i s and f u r t h e r t h a t the moral o b l i g a t i o n to inf o r m the p a t i e n t overshadows the p o t e n t i a l harm the i n f o r m a t i o n may cause (Barber, 1980). Most p h y s i c i a n s who make u n i l a t e r a l d e c i s i o n s about treatment o p t i o n s f o r p a t i e n t s base these d e c i s i o n s on maximizing the l e n g t h of the p a t i e n t ' s l i f e (Shephard, 1983). How t h a t l i f e i s lengthened, or at what p e r s o n a l c o s t to the p a t i e n t , i s not c o n s i d e r e d (Goro- v i t z , 1982). Seeking p a t i e n t p a r t i c i p a t i o n i n informed consent 5 has not been the accepted norm i n medi c a l c a r e . Even codes of e t h i c s have been i n f l u e n c e d by "the assumption t h a t i t i s f o r d o c t o r s a l o n e to d e c i d e what i s r i g h t and proper f o r t h e i r p a t i e n t s " (Barber, 1980, p. 29). "In some of the most c r i t i c a l of l i f e ' s moments, the average person does not have the r e q u i s i t e knowledge and power to make s u c c e s s f u l c h o i c e s i n h i s or her bes t i n t e r e s t s " (Dougherty, 1985, p. 94-95). P a t i e n t s depend, i n these s i t u a t i o n s , on p r o f e s s i o n a l knowledge, and the p r o f e s s i o n a l i s seen to have the power to make d e c i s i o n s . S p e c i a l codes of e t h i c s and p a t i e n t ' s r i g h t s have been developed to p r o t e c t the dependent p e r s o n . The duty to uphold these r i g h t s r e s t s w i t h the p r o f e s s i o n a l who must be i n f l u e n c e d i n h i s c h o i c e s and a c t i o n s by the i n t e r e s t s of the dependent person. In other words, "the p r o f e s s i o n a l i n a complex s o c i e t y i s a f i d u c i a r y agent f o r the maintenance and r e s t o r a t i o n of p r a c t i c a l p e r s o n a l autonomy i n the l i v e s of the (persons) whose i n t e r e s t s a re being s e r v e d " (Dougherty, 1985, p. 95). Pr e s s u r e s to move away from t h i s model have come from a broad c u l t u r a l change where "people c h a l l e n g e a u t h o r i t y and ... s u s p e c t the motives of many, i f not a l l , p r o f e s s i o n a l s (Harron e t . a l . , 1983, p. 91). The second model i s one of p a t i e n t c o o p e r a t i o n where the p h y s i c i a n i s p a t e r n a l i s t i c and the p a t i e n t assumes the r o l e of a j u v e n i l e c o o p e r a t o r . " P a t e r n a l i s m ... g e n e r a l l y r e f e r s to the p r a c t i s e of t r e a t i n g i n d i v i d u a l s i n the way a f a t h e r t r e a t s h i s 6 c h i l d r e n " (Beauchamp, 1981, p. 137). Two a s p e c t s of p a t e r n a l i s m are i d e n t i f i e d i n medical c a r e : b e n e f i c e n c e , and a primary r o l e as a d e c i s i o n maker. B e n e f i c e n c e , the p r i n c i p l e t h a t one 'ought' to do good, i s o f t e n "invoked as j u s t i f i c a t i o n f o r o v e r r i d i n g " a p a t i e n t ' s autonomy ( G o r o v i t z , 1982, p. 36). Thus, the p r e f e r - ences of the person being t r e a t e d may n e i t h e r be sought by the p h y s i c i a n nor expressed by the p a t i e n t (Beauchamp, 1981). T y p i c a l of t h i s model are statements such as: "The request f o r p e r m i s s i o n should be p r e s e n t e d to the p a t i e n t i n such a way t h a t he f e e l s he has no o p t i o n to r e f u s e . . i t i s best to be f i r m and a u t h o r i t a t i v e , s t r e s s i n g t h a t no o t h e r course i s p o s s i b l e " ( F i s h e r , 1977, as c i t e d i n Barber, 1980, p. 30). The p a t e r n a l - i s t i c p h y s i c i a n a c t s 'on b e h a l f o f 1 or ' f o r the b e n e f i t o f 1 the p a t i e n t ( C o l l i n s , 1984). P h y s i c i a n s o f t e n b e l i e v e t h a t i n order f o r a p a t i e n t to have the courage to a ccept a treatment i t i s best not to r e v e a l the u n c e r t a i n t i e s and r i s k s of the d i a g n o s t i c procedures or the treatment (Barber, 1980). However, more consumer e d u c a t i o n and communication has reduced p a t i e n t t o l e r - ance of t h i s p a t e r n a l i s m and p a t i e n t s are demanding an a c t i v e r o l e i n d e c i s i o n making i n h e a l t h care (Hoffman, 1985). The most rec e n t model to emerge, p a t i e n t p a r t i c i p a t i o n , d e s c r i b e s medical d e c i s i o n making as a j o i n t venture where the p a t i e n t has the r i g h t to be f u l l y informed and to f r e e l y g i v e consent to treatment. The s h i f t i n the r e l a t i v e importance of p a t i e n t p a r t i c i p a t i o n i n medical d e c i s i o n making has been due to 7 l e s s emphasis on the p r o f e s s i o n a l "duty to d i s c l o s e " i n f o r m a t i o n and more emphasis on the p a t i e n t ' s " r i g h t of a c c e s s " to informa t i o n (Harron, e t . a l . , 1983, p. 5 ) . T h i s s h i f t was demonstrated by Abram (1982) i n a survey t h a t r e p o r t e d t h a t 72% of the p u b l i c p o l l e d wanted to know treatment a l t e r n a t i v e s and then make a d e c i s i o n j o i n t l y with a p h y s i c i a n w h i l e 88% of p h y s i c i a n s p o l l e d s t a t e d t h a t they b e l i e v e d p a t i e n t s wanted treatment d e c i s i o n s made by a p h y s i c i a n . A number of good reasons have been o f f e r e d by Dougherty (1985) to support the c u r r e n t t r e n d toward more, i f somewhat mixed, acceptance of the p a t i e n t p a r t i c i p a t i o n model. The s t r o n g e s t argument f o r j o i n t d e c i s i o n making as proposed by t h i s model i s the p r o t e c t i o n of p a t i e n t autonomy. The val u e of p e r s o n a l autonomy has been a prominent f e a t u r e of the growing b i o e t h i c s l i t e r a t u r e w i t h i n the p a s t decade (Doudera, 1981). However, the n o t i o n of autonomy appears to be l e s s c e n t r a l to p h y s i c i a n s or to s e r i o u s l y i l l p a t i e n t s , as i n d i c a t e d by the s c a r c i t y of r e f e r e n c e s i n the medi c a l l i t e r a t u r e , than i t i s to p h i l o s o p h e r s concerned with modern medi c a l p r a c t i s e (White, 1983). The e a r l i e s t l e g a l r e c o r d of a commitment to autonomy as a p r i n c i p l e of law was made by Mr. J u s t i c e Cardozo of the United S t a t e s Supreme C o u r t , who s t a t e d i n 1914: "The root premise i s ... t h a t every human be i n g of a d u l t years and sound mind has a r i g h t to determine what s h a l l be done wi t h h i s own body" (White, 1983, p. 76). The q u a l i f i c a t i o n added by 'a d u l t y e a r s ' and 8 'sound mind' a l l a y s the problems c r e a t e d by u n q u a l i f i e d commit- ment to autonomy t h a t may a c t u a l l y hamper good med i c a l c a r e (Abrams, 1982) . F u l l autonomy i s not always p o s s i b l e , t h e r e f o r e "...the j o b of the p h y s i c i a n i s to h e l p the p a t i e n t m a i n t a i n h i s or her autonomy to the degree p o s s i b l e i n the f a c e of the i l l n e s s " ( C a s s e l l , 1983, p. 151). An example of l i m i t e d autonomy a r i s e s i n emergency medicine, where i n j u r i e s to the p a t i e n t may prevent communication or d e c i s i o n making by anyone oth e r than the p h y s i c i a n . In terms of c h r o n i c and d e g e n e r a t i v e d i s e a s e s , " p h y s i c i a n s a r e c o n s u l t a n t s to p a t i e n t s , and p a t i e n t s , not p h y s i c i a n s , must f i n a l l y d e c i d e upon t h e i r own best i n t e r e s t s " (Doudera, 1981, p. 106). "Our i d e a l of the autonomous person e n t a i l s t h a t p a t i e n t s have a r i g h t t o . . . g i v e or w i t h h o l d informed consent over a l l a s p e c t s of t h e i r c a r e " (Dougherty, 1985, p. 98). To remain autonomous and make reas o n a b l e c h o i c e s , p a t i e n t s have the r i g h t to know: what i s being done and why, the r i s k of the proposed a c t i o n s compared to a l t e r n a t i v e s , and the outcomes of no t r e a t - ment . The i n c r e a s i n g r o l e of t e c h n o l o g i c a l advancement i s the second reason f o r i n c r e a s e d p a t i e n t p a r t i c i p a t i o n . As more i n n o v a t i o n s appear i n medi c a l c a r e , the p o t e n t i a l i n c r e a s e s to extend l i f e , c o n t r o l b e h a v i o u r , and engineer r e p r o d u c t i o n . Such i n n o v a t i o n s generate a range of c h o i c e s dependant on s o c i a l , p e r s o n a l , and p o l i t i c a l c o n s i d e r a t i o n s (Evans, 1985). Humane medicine i n t h i s c o n t e x t w i l l r e q u i r e shared i n f o r m a t i o n and p a r t i c i p a t i o n i n d e c i s i o n making by many a f f e c t e d p e r s o n s . T h i r d , as the p a t t e r n s of d i s e a s e change i n developed c o u n t r i e s , c h r o n i c and d e g e n e r a t i v e d i s e a s e s become the major c o n t r i b u t o r s to m o r b i d i t y and m o r t a l i t y . The treatment of these d i s e a s e s o f t e n r e q u i r e c o n s i d e r a b l e commitment on the p a r t of the p a t i e n t . T h i s l e a d s to the f o u r t h reason, the f i n d i n g t h a t mutual p a r t i c i p a t i o n generates b e t t e r treatment outcomes. When p a t i e n t s understand t h e i r c o n d i t i o n they are more e a s i l y m o t i - vated to t r y to improve i t . P a r t i c i p a t i o n i n the c h o i c e of a treatment i n c r e a s e s p a t i e n t compliance w i t h what may be a l i f e t i m e of m e d i c a t i o n and s i d e - e f f e c t s . F i n a l l y , t h r e e a s p e c t s of p a t i e n t - p h y s i c i a n i n t e r a c t i o n a r e improved by p a r t i c i p a t i o n . S a t i s f a c t i o n of p h y s i c i a n s tends to be improved by m a i n t a i n i n g the human worth of the p a t i e n t as a d e c i s i o n maker; the p h y s i c i a n ' s p r o f e s s i o n a l r e p u t a t i o n as a ' h e a l e r ' i s enhanced; and consumer a l i e n a t i o n and c y n i c i s m i s reduced. 1.3. Informed Consent The m e d i c a l p r o f e s s i o n has t r a d i t i o n a l l y c h a l l e n g e d the concept of autonomy where the i n d i v i d u a l p a t i e n t makes the f i n a l d e c i s i o n h i m s e l f , r e g a r d i n g e i t h e r h i s own a c t i o n s or the a c t i o n s 10 of o t h e r s towards him.2 In some cas e s , an i n d i v i d u a l ' s r i g h t to i n d i v i d u a l d e c i s i o n making i s sub v e r t e d by c i r c u m s t a n c e s , such as a s e r i o u s a c c i d e n t , or a d i s a b l i n g h e a r t a t t a c k . A p a t i e n t may not be c o n s i d e r e d f u l l y competent to make a r a t i o n a l c h o i c e about treatment when he/she i s s u f f e r i n g from p a i n or mental i l l n e s s ( F o r r e s t , 1984). I f a p a t i e n t i s competent, the p h y s i c i a n i s e t h i c a l l y bound to seek 'informed c o n s e n t 1 from the p a t i e n t f o r any procedure t h a t c a r r i e s a r i s k . 3 The term 'informed consent' d e r i v e s i t s meaning from the ' d i s c l o s u r e ' r e q u i r e d by the word 'informed', and from the 'awareness or a s s e n t ' r e q u i r e d by the word * c o n s e n t 1 . Informed consent i s a procedure t h a t embodies consumer s o v e r e i g n t y or autonomy of c h o i c e . Consent i s important be- cause: " p h y s i c i a n s do the s o r t s of t h i n g s to t h e i r p a t i e n t s t h a t people i n g e n e r a l cannot j u s t i f i a b l y do to one another" (Goro- v i t z , 1982, p. 38). I f the p a t i e n t i s informed and co n s e n t s , then m e d i c a l i n t e r v e n t i o n i s no lon g e r a s s a u l t , but s e r v i c e . The p h y s i c i a n must inf o r m the p a t i e n t about: what the procedure e n t a i l s , the a l t e r n a t i v e s a v a i l a b l e , the problems that may a r i s e d u r i n g r e c o v e r y , the r i s k s of the treatment, and any other 2 I n d i v i d u a l d e c i s i o n making, or autonomy, i s what econo- m i s t s c a l l 'consumer s o v e r e i g n t y ' . 3 A r i s k i s d e f i n e d as some p r o b a b i l i t y of a l o s s . For a p a t i e n t w i t h h e a r t d i s e a s e , t h i s l o s s c o u l d be measured as death, c o n t i n u i n g d i s a b i l i t y due to angina, or i n c r e a s e d d i s a b i l i t y c a u s i n g work l o s s or l i f e s t y l e change. 11 r e a s o n a b l e i n f o r m a t i o n (Grad, 1984). Some p h y s i c i a n s argue t h a t a p a t i e n t i s o f t e n not capable of t r u l y informed consent because the i n f o r m a t i o n p r o v i d e d i s too complex, or t h a t t r u t h f u l or complete i n f o r m a t i o n w i l l f r i g h t e n the p a t i e n t . However, informed consent, a c c o r d i n g to the Supreme Court of Canada, i s now to be judged by the wishes and p r e f e r e n c e s of the p a t i e n t and not the sta n d a r d s of the medical p r o f e s s i o n (Hoffman, 1985). An important study by A l f i d i (1971) examined the degree to which informed p a t i e n t s r e f u s e d to undergo a d i a g n o s t i c procedure (angiography) to e v a l u a t e the s e r i o u s n e s s of h e a r t d i s e a s e . P a t i e n t s who c o u l d p o t e n t i a l l y b e n e f i t from t h i s procedure were informed about i t s r i s k s , d i s c o m f o r t s and c o m p l i c a t i o n s i n " s t r a i g h t f o r w a r d and even h a r s h " terms ( A l f i d i , 1971, p. 1325). O v e r a l l , 228 out of 232 p a t i e n t s i n the study consented to the d i a g n o s t i c p r o c e d u r e . The study concluded t h a t p a t i e n t s have a d e s i r e to know, and 'should' know the r i s k s of a procedure. "The concern t h a t i n f o r m i n g the p a t i e n t of p o s s i b l e c o m p l i c a t i o n s w i l l r e s u l t i n h i s r e f u s a l of the procedure i s now outmoded" ( A l f i d i , 1971, p. 1329). Barber (1980) c a u t i o n s a g a i n s t g e n e r a l i z i n g to othe r p o p u l a t i o n s and procedures from t h i s one study, but suggests t h a t t h i s i s indeed e v i d e n c e to support the argument i n favo u r of t r u l y informed consent. Evidence has a l s o been produced to i n d i c a t e t h a t p a t i e n t s may not want to be informed of ' a l l ' the i n f o r m a t i o n a v a i l a b l e to t h e i r p h y s i c i a n . In a study of pregnant women r e c e i v i n g a 12 d i a g n o s t i c procedure (amniocentesis) to i d e n t i f y b i r t h d e f e c t s , Berwick e t . a l . (1985) found t h a t over h a l f of the p a t i e n t s d i d not want to know the sex of the baby. They wanted i t to 'be a s u r p r i s e ' . S i m i l a r l y , i n a study of cancer p a t i e n t s , Mcintosh (1976) found t h a t none of the 74 p a t i e n t s i n the study wanted to know when the p h y s i c i a n expected the p a t i e n t to d i e . However, i t i s important to note here, t h a t p a t i e n t s were asked about w i t h h o l d i n g i n f o r m a t i o n t h a t had l i t t l e r e l e v a n c e to the t r e a t - ment d e c i s i o n needed i n each c a s e . In summary, informed consent must be based on a knowledge of the p a t i e n t ' s p r e f e r e n c e s f o r treatment outcomes, not j u s t i n terms of q u a n t i t y (or a d d i t i o n a l years) of l i f e , but q u a l i t y of those years as w e l l . P a t i e n t s must be allowed to choose a treatment t h a t may, i n the o p i n i o n of the a t t e n d i n g p h y s i c i a n , not be the most e f f e c t i v e . As G o r o v i t z (1982, p. 45) has s t a t e d : " t h e r e i s no reason to b e l i e v e t h a t the p r o s p e c t f o r m e d i c a l success i s the o n l y r e l e v a n t b a s i s , or ought always to be the dominant b a s i s , f o r e x e r c i s i n g c h o i c e i n m e d i c a l s i t u a - t i o n s . " The normative argument i s t h a t p a t i e n t p r e f e r e n c e s 'ought' to matter f o r a number of reasons (Barber, 1980). In p r a c t i s e , they do not always seem to be g i v e n primary c o n s i d e r a - t i o n . 1.4. A t t r i b u t e s of M e d i c a l D e c i s i o n Making M e d i c a l or c l i n i c a l d e c i s i o n making has been d e f i n e d as a 13 way of s t r u c t u r i n g p a t i e n t v a l u e s and p r o b a b i l i t i e s of treatment outcomes so t h a t p a t i e n t autonomy can be e x e r c i s e d under the guidance of a p h y s i c i a n (Pauker, 1976). In t h i s way, r i s k s , b e n e f i t s , and the p r o b a b i l i t i e s of these o c c u r r i n g become c l e a r to the p a t i e n t , and are t h e r e f o r e a b l e to improve the p a t i e n t ' s d e c i s i o n making (Lusted, 1968; W e i n s t e i n e t . a l . , 1979). A m e d i c a l (or c l i n i c a l ) d e c i s i o n i s g e n e r a l l y the r e s u l t of t h r e e components. The f i r s t i s the v a l u e assessment ( u t i l i t y ) of a treatment outcome f o r the p a t i e n t i n c l u d i n g r e l i e f from symptoms, the p r e v e n t i o n of adverse drug or treatment r e a c t i o n s , and the c o n t r o l of c o s t of c a r e . The second i s a d e t e r m i n a t i o n of t h r e e p r o b a b i l i t i e s : t h a t the treatment w i l l improve the h e a l t h of the p a t i e n t , t h a t the treatment may cause harm to the p a t i e n t ( i n c l u d i n g the r i s k of d e a t h ) , or t h a t the treatment w i l l do n o t h i n g ( S h a p i r o , 1977). T h i r d , the i n t e r e s t s of the p h y s i c i a n shape the c h o i c e because of the p h y s i c i a n ' s t r a d i t i o n a l r o l e i n d i a g n o s i s as w e l l as treatment (Evans, 1985). The v a l u e assessment component of m e d i c a l d e c i s i o n making i s l i k e the law, which i n the B r i t i s h t r a d i t i o n , has been pragma- t i c . Both d i s c i p l i n e s "respond to changing c i r c u m s t a n c e s with a minimum of s p e c u l a t i o n and t h e o r i z i n g , thereby m a i n t a i n i n g a f i r m rootage i n the immediate, c o n c r e t e human problems under s c r u - t i n y " (White, 1983, p. 73). Law and medicine have been grounded on a consensus of moral and e t h i c a l p r i n c i p l e s , one of which i s r e s p e c t f o r autonomy. 14 The Canadian C h a r t e r of R i g h t s and Freedoms f o r m a l i z e s autonomy i n the r i g h t of freedom of b e l i e f s and speech, the r i g h t to p r i v a c y , the r i g h t to s e l f - d e t e r m i n a t i o n , and the r i g h t to d e c i d e what w i l l happen to one's own body. The r h e t o r i c of i n d i v i d u a l r i g h t s i s sometimes cl o u d y , but the d e l i b e r a t i o n s of d e c i s i o n making p r o c e s s e s aim to c l a r i f y the f a c t s , i s s u e s and va l u e s n e c e s s a r y to make meaningful d e c i s i o n s . In a d d i t i o n , c o n t r i b u - t i o n s to c l i n i c a l d e c i s i o n s made by p a t i e n t ' s v a l u e s w i l l l i k e l y cause e x p l o r a t i o n and q u e s t i o n i n g of assumptions of presumed p h y s i c i a n wisdom i n matters of l i f e and death ( C a r l t o n , 1978). "The wrong d e c i s i o n from a p u r e l y m e d i c a l p o i n t of view may ... not be the wrong d e c i s i o n from the broader p e r s p e c t i v e of the p a t i e n t ' s l i f e ( G o r o v i t z , 1982, p. 46). The second component of medical d e c i s i o n making i n v o l v e s some p r e d i c t i o n s of outcomes of a c t i o n s . The purpose of making d e c i s i o n s i s to a l t e r and improve outcomes of f u t u r e e v e n t s . To make an i n t e l l i g e n t or r a t i o n a l c h o i c e , one would l i k e to be a b l e to p r e d i c t the outcomes of those c h o i c e s (Arrow, 1965) . However, i n c l i n i c a l m e d i c i n e , as i n many other d e c i s i o n making s i t u a - t i o n s , the best one can do i s o f f e r a p r e d i c t i o n i n terms of a p r o b a b i l i t y based on evidence of past events t h a t d e s c r i b e s the l i k e l i h o o d of some f u t u r e event. P r o b a b i l i t y i s the mechanism used f o r q u a n t i f y i n g a r i s k . When r i s k i s d e f i n e d as a chance of i n j u r y or l o s s , many of l i f e ' s a c t i v i t i e s can be viewed as r i s k y ( C h i l d r e s s , 1982; 15 MacCrimmon and Wehrung, 1985) "In o r d i n a r y d i s c l o s u r e , ' r i s k ' r e f e r s to the amount of p o s s i b l e l o s s and the p r o b a b i l i t y of t h a t l o s s . ' R i s k - t a k i n g ' i m p l i e s t h a t the a c t o r i s aware of the r i s k s and v o l u n t a r i l y assumes them." ' R i s k - i m p o s i t i o n ' " r e f e r s to conduct t h a t imposes r i s k on o t h e r s . " ( C h i l d r e s s , 1982, p. 227)4 There are a number of p r o b a b i l i t i e s t h a t are important i n d e c i s i o n making i n h e a l t h c a r e . F i r s t , the p r o b a b i l i t y of a c o r r e c t d i a g n o s i s depends on a d o c t o r ' s a b i l i t y to r e c o g n i z e s i g n s or symptoms and i n t e r p r e t d i a g n o s t i c e v i d e n c e . Second, the p r o b a b i l i t y t h a t a treatment w i l l a l t e r the course of the d i s e a s e i s l e s s than c e r t a i n t y and t h i s may be i n f l u e n c e d by many v a r i a b l e s ( S h a p i r o , 1977; B u r s z t a j n and Hamm, 1979). B u r s z t a j n e t . a l . (1981) are proponents of a " p r o b a b i l i s t i c paradigm" t h a t i n c o r p o r a t e s these u n c e r t a i n t i e s . However, they suggest t h a t d o c t o r s and p a t i e n t s have e x p e c t a t i o n s grounded i n the " m e c h a n i s t i c paradigm" f i r s t d e s c r i b e d by Claud Bernard i n 1865 i n P r i n c i p l e s of E x p e r i e n t i a l Medicine.5 To change t h i s m e c h a n i s t i c approach, B u r s z t a j n e t . a l . (1981) have recommended f i r s t , t h a t d o c t o r s and p a t i e n t s should r e a l i z e t h a t symptoms may r e l a t e to a number of causes w i t h v a r y i n g e f f e c t s . Second, d i a g n o s t i c procedures s h o u l d be viewed as gambles, not as methods 4 To g i v e a t r u l y informed consent i m p l i e s t h a t the p a t i e n t i s r i s k - t a k i n g w h i l e the p h y s i c i a n i s not r i s k - i m p o s i n g . 5 Bernard s t a t e d t h a t s c i e n t i f i c laws are based on c e r t a i n - t y , not p r o b a b i l i t y . S c i e n t i f i c laws, and the laws of medicine are d e r i v e d from the p r i n c i p l e s of e x p e r i m e n t a t i o n and d e t e r m i n i - sm i n s c i e n c e - a m e c h a n i s t i c approach. 16 f o r d e t e r m i n i n g cause. T h i r d , the p a t i e n t ' s v a l u e s , p r e f e r e n c e s and knowledge are as important i n the c h o i c e of treatment as the d o c t o r ' s knowledge and e x p e r i e n c e . F i n a l l y , i t s h o u l d be acknowledged t h a t treatment cannot guarantee e l i m i n a t i o n of symptoms or the u n d e r l y i n g d i s e a s e and treatment can a c t u a l l y make a p a t i e n t worse o f f ( I l l i c h , 1974). The t h i r d component, p h y s i c i a n p r e f e r e n c e s , were not a t o p i c of t h i s study. T h i s o m i s s i o n was j u s t i f i e d by assuming t h a t i f a p h y s i c i a n understood a p a t i e n t ' s p r e f e r e n c e s t h a t he/she would p r o v i d e treatment t h a t would maximize the p a t i e n t ' s autonomy and f e e l i n g of a s a t i s f a c t o r y h e a l t h outcome. The weaknesses of t h i s assumption have been d e s c r i b e d by Evans (1984) and i n the d i s c u s s i o n of the models of p a t i e n t p a r t i c i p a t i o n i n s e c t i o n 1.2 above. 1.5. U n c e r t a i n t y i n C l i n i c a l M e d i c i n e : a Component of R i s k When the p h y s i c i a n e l e c t s to i n i t i a t e treatment, he/she operates i n an environment of u n c e r t a i n t y , p a r t of which i s due to " u n i n t e n t i o n a l and p o t e n t i a l l y hazardous consequences" t h a t can occur every time a d o c t o r makes a move ( I s r a e l , 1982, p. 10). In any t h e r a p e u t i c d e c i s i o n t h e r e i s some u n c e r t a i n t y about the outcomes of a l t e r n a t i v e modes of treatment. U n c e r t a i n t y about treatment modes and outcomes i n c l i n i c a l medicine i s a combina- t i o n of u n c e r t a i n t i e s about: the causes of d i s e a s e , the mechanism of d i s e a s e , i n d i v i d u a l d i f f e r e n c e s i n the response to treatment, 17 and the dangers of drugs to i n d i v i d u a l s . There i s a l s o u n c e r t a i n t y about the a c c u r a c y of a d i a g n o s i s i n m e d i c a l care ( E l s t e i n , 1976). P h y s i c i a n s g e n e r a l l y combine u n c e r t a i n data from d i a g n o s t i c t e s t s , weigh c o n f l i c t i n g e vidence and use i n f o r m a l means to make judgements on a course of a c t i o n ( G o r o v i t z , 1982). The r o l e of the p a t i e n t i n these judgements may be u n c l e a r to both the p h y s i c i a n and the p a t i e n t . U n c e r t a i n t y i s a p a r t of our d a i l y l i v e s whether we are s i c k or w e l l . Doctors tend to i g n o r e many as p e c t s of u n c e r t a i n t y i n t h e i r d i s c u s s i o n s w i t h p a t i e n t s . They may d i s t o r t the s t o r y not on l y f o r the p a t i e n t , but f o r themselves as w e l l . I f p h y s i c i a n s d e a l t w i t h u n c e r t a i n t y i n a way th a t would maximize the d e c i s i o n making a b i l i t y of the p a t i e n t they might employ the f o l l o w i n g f i v e s t e p s : d e f i n e and d e s c r i b e the a v a i l a b l e a l t e r n a t i v e s f o r the p a t i e n t , admit to u n c e r t a i n t i e s about which i s the bes t treatment c h o i c e , e l i c i t p a t i e n t p r e f e r e n c e s , t r y to understand the reasons f o r those p r e f e r e n c e s , and make a treatment recommen- d a t i o n to which the p h y s i c i a n i s not bound (Katz, 1984). In a c t u a l f a c t , t h i s s t r a t e g y i s seldom p r a c t i s e d . M e d i c a l a d v i c e from a p h y s i c i a n i s o f t e n the most i n f l u e n t i a l f a c t o r i n a p a t i e n t ' s u n derstanding and acceptance of a treatment ( G o r o v i t z , 1982). P h y s i c i a n s s t a t e t h a t p a t i e n t s do not want to d i s c u s s u n c e r t a i n t y , and t h a t such d i s c u s s i o n s cause a n x i e t y . They a l s o s t a t e t h a t p a t i e n t s cannot p o s s i b l y understand complex med i c a l problems. Doctors e x p r e s s , i n s t e a d , c e r t a i n t y about treatment 18 c h o i c e (based on a r i g i d treatment p h i l o s o p h y ) as p a r t of t h e i r s o c i a l i z e d , p a t e r n a l i s t i c views about p a t i e n t s and the d o c t o r - p a - t i e n t r e l a t i o n s h i p ( W a i t z k i n and S t o e k l e , 1972; Katz, 1984). 1.6. R e p r e s e n t i n g Risk i n M e d i c a l D e c i s i o n Making Risk has been d e f i n e d as the chance of a l o s s , which i s expressed i n d e c i s i o n making by a p r o b a b i l i t y ( C h i l d r e s s , 1982; Keeny and R a i f f a , 1976; MacCrimmon and Wehrung, 1985). P a t i e n t s have demonstrated the a b i l i t y to understand and to use p r o b a b i l - i t i e s when they i n d i c a t e p r e f e r e n c e s based on d i a g n o s t i c i n f o r m a - t i o n . For example, Pauker e t . a l . (1981) have i n d i c a t e d t h a t p a r e n t s s e e k i n g g e n e t i c c o u n s e l l i n g can d i f f e r e n t i a t e the r i s k s a s s o c i a t e d w i t h b e a r i n g a deformed c h i l d and the r i s k of an a b o r t i o n . When the p r o b a b i l i t y of g i v i n g b i r t h to a deformed i n f a n t r o s e , the number of p a r e n t s c h o o s i n g an e l e c t i v e a b o r t i o n a l s o r o s e . Throughout t h i s study, p r o b a b i l i t i e s are expressed as a s i n g l e number wherever p o s s i b l e so as to a v o i d the problem of ambiguity. Ambiguity, i n t h i s c o n t e x t , can be d e s c r i b e d as a s i t u a t i o n where the outcomes of an a c t i o n (or treatment) are d e s c r i b e d by a range of p r o b a b i l i t i e s . E l l s b e r g (1964) showed th a t i f s u b j e c t s were o f f e r e d a c h o i c e between two gambles - one with an outcome d e s c r i b e d i n terms of r i s k (a p r e c i s e outcome) and one w i t h an ambiguous outcome (the p r o b a b i l i t y i s g i v e n as a range), most s u b j e c t s w i l l p r e f e r the former even i f the proba- 19 b i l i t i e s a r e s i m i l a r . E l l s b e r g (1961) c a l l e d t h i s behaviour ambiguity avoidance. S u b j e c t s i n d e c i s i o n making s i t u a t i o n s i n h e a l t h c a r e have been shown t o be w i l l i n g t o pay to a v o i d such ambiguity ( C u r l e y e t . a l . , 1985). Two f a c t o r s a re important i n u n d e r s t a n d i n g a p a t i e n t ' s response t o the r i s k s i t u a t i o n i n medi c a l c a r e . F i r s t , t h e r e i s the event t h a t g i v e s r i s e to the p o t e n t i a l r i s k , and, second t h e r e i s the p r o b a b i l i t y t h a t a treatment or i n t e r v e n t i o n w i l l reduce the r i s k . The second p r o b a b i l i t y i s o f t e n c a l l e d an outcome p r o b a b i l i t y . Two p e r s p e c t i v e s of p r o b a b i l i t y a re used i n medi c a l d e c i s i o n making: o b j e c t i v e and s u b j e c t i v e . O b j e c t i v e p r o b a b i l i t y i s o f t e n d e f i n e d i n me d i c a l d e c i s i o n making as a p r o b a b i l i t y judgement by an e x p e r t . I t may be based on e p i d e m i o l o g i c a l data from s i m i l a r p o p u l a t i o n s r e c e i v i n g s p e c i f i e d t r e a t m e n t s . The c a l c u l a t i o n of t h i s p r o b a b i l i t y i s u s u a l l y made by a p h y s i c i a n combining p r e v i o u s knowledge about s i m i l a r cases w i t h i n f o r m a t i o n on the symptoms and d i a g n o s t i c t e s t r e s u l t s of the new p a t i e n t . S u b j e c t i v e p r o b a b i l i t y i n t h i s c o n t e x t i s d e f i n e d as the l i k e l i h o o d of v a r i o u s treatment outcomes made by the p a t i e n t . T h i s measure may be d e r i v e d from the p a t i e n t ' s u n derstanding of the p h y s i c i a n ' s assessment of the o b j e c t i v e p r o b a b i l i t y . In p r a c t i c a l terms, i t i s u s u a l l y n e c e s s a r y to make an e v a l u a t i o n of the p a t i e n t ' s a b i l i t y or c a p a c i t y to a c h i e v e an adequate l e v e l of unde r s t a n d i n g of the o b j e c t i v e p r o b a b i l i t i e s of treatment 20 outcomes ( G o r o v i t z , 1982) . Two fundamental p e r s p e c t i v e s of o b j e c t i v e p r o b a b i l i t i e s have been exp r e s s e d . Savage (1954) has s t a t e d t h a t t h e r e are no o b j e c t i v e p r o b a b i l i t i e s , a r g u i n g t h a t a l l d e c i s i o n s are f u t u r e o r i e n t e d and t h e r e i s no r e c o r d of such e v e n t s . I s r a e l (1982, p. 82) has c o n d i t i o n a l l y supported Savage's argument by s t a t - i n g : "In some circ u m s t a n c e s i t i s v i r t u a l l y i m p o s s i b l e to es t i m a t e o b j e c t i v e p r o b a b i l i t i e s (based on r e l a t i v e f r e q u e n - c i e s ) . " Edwards (1962) has taken the o t h e r s i d e of the argument, a s s e r t i n g t h a t e s t a b l i s h e d p r o b a b i l i t i e s can e a s i l y be compared to p r o b a b i l i t i e s r e v e a l e d by d e c i s i o n s i n v o l v i n g f u t u r e e v e n t s . In t h i s way, the outcome of an i n d i v i d u a l case updates o b j e c t i v e (outcome) p r o b a b i l i t i e s c o l l e c t e d from a l l p r e v i o u s c a s e s . In s t u d i e s of medi c a l d e c i s i o n making, e p i d e m i o l o g i c a l r e c o r d s of treatment outcomes are t r e a t e d as o b j e c t i v e p r o b a b i l i t i e s (Pauker, 1976). The a t t i t u d e of a p a t i e n t toward r i s k - t a k i n g or a c c e p t i n g a r i s k y treatment i s a f u n c t i o n of t h r e e judgements the p a t i e n t must make about h i s / h e r s i t u a t i o n . F i r s t , the p a t i e n t must make an a p p r a i s a l of the l e v e l of r i s k (a s u b j e c t i v e p r o b a b i l i t y ) . Tversky (1972) has s t a t e d t h a t t h i s a p p r a i s a l may be b i a s e d because h i s study found t h a t s u b j e c t s o v e r e s t i m a t e d low o b j e c t i v e p r o b a b i l i t i e s and underestimated h i g h ones. Second, the p a t i e n t must have some i n t e r n a l measure of the a n x i e t y caused by being i n the r i s k y s i t u a t i o n . T h i r d , the p a t i e n t must make an e s t i m a t e of 21 the e f f e c t of the remedial a c t i o n (Mooney, 1977). T h i s e s t i m a t i o n i s made d i f f i c u l t by the nec e s s a r y comparison of v e c t o r s of treatment outcomes and the dominance of some a s p e c t s of the treatment p r o c e s s . I t i s the p a t i e n t , I s r a e l s t a t e s (1982, p. 82) who must make t h i s e s t i m a t e , because: "..no two medical cases are a l i k e , c o n s i d e r i n g p s y c h o l o g i c a l d i f f e r e n c e s at the o u t s e t , whether the d i s e a s e i s e v o l v i n g r a p i d l y or s l o w l y , and the v a r i a b l e e f f e c t s of the m e d i c a t i o n . " B u r s z t a j n e t . a l . (1981) have s t a t e d t h a t o b j e c t i v e p r o b a b i l - i t i e s a re t r a n s l a t e d i n t o s u b j e c t i v e p r o b a b i l i t i e s by comparing the h e a l t h v a r i a b l e s of a s t a t i s t i c a l p o p u l a t i o n (using a c t u a r i a l t a b l e s ) to the h e a l t h v a r i a b l e s of the p a t i e n t . While the p h y s i c i a n i s i n a p o s i t i o n to d e s c r i b e the o b j e c t i v e r i s k s , he cannot t e l l the p a t i e n t how to weigh the r i s k of death a g a i n s t a chance of reduced angina p a i n . P a t i e n t p r e f e r e n c e determines the t r a d e - o f f between p a i n and r i s k of death or other l i f e r e s t r i c - t i o n s . These p a t i e n t judgements determine the r e l a t i v e importance of one s t a t e of h e a l t h over another. P a t i e n t s may a l s o demon- s t r a t e d i f f e r e n t l e v e l s of a n x i e t y a s s o c i a t e d w i t h s i m i l a r l e v e l s of o b j e c t i v e r i s k due to i n e x p e r i e n c e w i t h the r i s k , or d i f f e r e n t response mechanisms f o r d e a l i n g w i t h r i s k . T h e r e f o r e , one expects d i f f e r e n t v a l u e s to be a t t a c h e d to the same treatment outcome by d i f f e r e n t p a t i e n t s . For example, i f p a t i e n t s s t a t e t h e i r l i f e expectancy, i t can be used as an approximation of the s u b j e c t i v e r i s k p a t i e n t s a p p l y 22 to the s e r i o u s n e s s of t h e i r d i s e a s e and the p r o b a b i l i t y that i t w i l l k i l l them prematurely. To rou g h l y determine the s u b j e c t i v e p r o b a b i l i t y a p a t i e n t p l a c e s on h i s / h e r l i f e expectancy, a r a t i o can be c a l c u l a t e d from the p a t i e n t ' s expectancy e s t i m a t e and the ( o b j e c t i v e ) l i f e expectancy of the p a t i e n t drawn from a c t u a r i a l t a b l e s (Edwards, 1962). A c t u a r i a l t a b l e s p r e s e n t some problems due to t h e i r r e p r e s e n t a t i o n of the g e n e r a l p o p u l a t i o n and not the p o p u l a t i o n of p a t i e n t s at r i s k . A number of experiments on r i s k t a k i n g behaviour have been done w i t h h y p o t h e t i c a l s i t u a t i o n s (Kahneman and Tversky, 1979; Knetsch and Sinden, 1984; T h a l e r , 1980). Some have been done on s u b j e c t s u s i n g l i m i t e d money bets as the r i s k . S t u d i e s of p a t i e n t ' s responses to r i s k have been r e p o r t e d f o r cancer p a t i e n t s (McNeil e t . a l . , 1978) and women r e c e i v i n g d i a g n o s t i c t e s t s f o r b i r t h d e f e c t s (Berwick and W e i n s t e i n , 1985). These s t u d i e s are reviewed i n d e t a i l i n Chapter 3. In a study of the e f f e c t of p o s i t i v e f e e l i n g s on r i s k t a k i n g among student s u b j e c t s , Isen and P a t r i c k (1983) used r e a l r i s k ( r o u l e t t e ) and a h y p o t h e t i c a l dilemma (job change). The authors found t h a t h y p o t h e t i c a l r i s k was l e s s e f f e c t e d by s u b j e c t ' s f e e l i n g s than r i s k t a k i n g w i t h r e a l r e s o u r c e s . In a d d i t i o n , they s t a t e d t h a t people " e x h i b i t more bravado when t h e r e i s l i t t l e chance of a c t u a l l y l o s i n g " (Isen and P a t r i c k , 1983, p. 200). Jones-Lee (1976) noted t h r e e b e h a v i o u r a l c h a r a c t e r i s t i c s of people i n a r i s k - t a k i n g s i t u a t i o n t h a t are of importance to the 23 p r e s e n t study of heart d i s e a s e p a t i e n t s . F i r s t , a p a t i e n t w i l l not bankrupt h i m s e l f f o r any r e d u c t i o n i n r i s k o ther than a complete r e d u c t i o n . Second, i f the p a t i e n t i s i n a s i t u a t i o n where r i s k i s p o t e n t i a l l y i n c r e a s i n g , no amount of compensation i s l i k e l y to be a b l e to induce the p a t i e n t to take a l a r g e r r i s k . T h i r d , the marginal v a l u e to the p a t i e n t of a r e d u c t i o n i n r i s k w i l l be p o s i t i v e and i n c r e a s i n g as the r i s k i s reduced toward z e r o . In p r e s e n t i n g t h i s argument, Jones-Lee (1974) assumes t h a t a person p r e f e r s a low p r o b a b i l i t y of death to a h i g h p r o b a b i l i t y , and t h a t t h i s person would f o r f e i t some of h i s p r e s e n t wealth to a t t a i n the low p r o b a b i l i t y . B e f o r e c o n c l u d i n g t h i s s e c t i o n on measuring r i s k , i t i s u s e f u l to i d e n t i f y b r i e f l y the types of r i s k the study has attempted to measure. A l i s t of e l i g i b l e r i s k s drawn from Mishan (1971) c o n s i s t s of f o u r b a s i c t y p e s : d i r e c t , d i r e c t - i n v o l u n t a r y , f i n a n c i a l , and p s y c h i c . D i r e c t r i s k s are those people assume v o l u n t a r i l y and can be d e s c r i b e d i n h e a l t h care as a demand f o r s e r v i c e s t h a t have an i n h e r e n t r i s k f a c t o r . D i r e c t - i n v o l u n t a r y r i s k s are those people bear without a c o n s c i o u s d e c i s i o n , such as r a d i a t i o n or h o s p i t a l induced i n f e c t i o n s . A f i n a n c i a l r i s k i s a monetary l o s s (or gain) t h a t i s born due to someone's death, w h i l e a p s y c h i c r i s k i s the sadness e x p e r i e n c e d at the death or d i s a b i l i t y of a c h e r i s h e d i n d i v i d u a l . T h i s study measured the v a l u e to a p a t i e n t of a r e d u c t i o n i n the r i s k of death, a d i r e c t r i s k , which Mishan f e e l s i s the o n l y approach t h a t makes sense i n 24 t h e o r e t i c a l terms. D i r e c t - i n v o l u n t a r y r i s k s a re r e f l e c t e d i n the o b j e c t i v e p r o b a b i l i t i e s of treatment outcomes d e s c r i b e d i n the f o l l o w i n g s e c t i o n on coro n a r y h e a r t d i s e a s e i n Canada. However, the study d i d not attempt to measure f i n a n c i a l or p s y c h i c r i s k . F i n a n c i a l r i s k i s not an i s s u e i n Canada, where h e a l t h c a r e i s p u b l i c l y s u p p o r t e d , and p s y c h i c r i s k was an i n a p p r o p r i a t e measure f o r treatment c h o i c e s the p a t i e n t s made f o r themselves, r a t h e r than f o r someone e l s e . 1.6. Summary The p r e s e n t study of p a t i e n t p r e f e r e n c e s has been i n t r o d u c e d through a d i s c u s s i o n of the reasons f o r g r e a t e r a t t e n t i o n to the p r o t e c t i o n of p a t i e n t autonomy and the c r i t e r i a f o r informed consent. Evidence has been pr e s e n t e d on the use of p r o b a b i l i t i e s to d e s c r i b e the r i s k s of treatment outcomes and the u n c e r t a i n t i e s i n h e r e n t i n treatment, two important f a c t o r s i n the decision-mak- i n g p r o c e s s i n medi c a l c a r e ( H i a t t , 1975). The f o l l o w i n g s e c t i o n i s devoted to a d i s c u s s i o n of the epidemiology, treatment o p t i o n s and c o s t s of treatment of coron a r y h e a r t d i s e a s e . I t i n c l u d e s : d e f i n i t i o n s o f medical terms i n t h e i r h i s t o r i c a l c o n t e x t , a d e s c r i p t i o n of the symptoms and treatment p r o t o c o l s , and i n f o r m a t i o n on the h o s p i t a l use a t t r i b u t a b l e to coro n a r y and o t h e r types of he a r t d i s e a s e i n Canada. T h i s i n f o r m a t i o n forms the b a s i s f o r the treatment a l t e r n a t i v e s a v a i l a b l e f o r p a t i e n t s and the o b j e c t i v e p r o b a b i l i - 25 t i e s t h a t d e s c r i b e the r i s k s a s s o c i a t e d w i t h the treatments, which are used i n c o n c e r t w i t h p a t i e n t p r e f e r e n c e s to make a medical d e c i s i o n . SECTION TWO CORONARY HEART DISEASE: H i s t o r y , Epidemiology, and Economics 2.0 The C l i n i c a l H i s t o r y of Coronary Heart Disease The h i s t o r y of our c u r r e n t c l i n i c a l u n d e r s t a n d i n g of coronary h e a r t d i s e a s e began i n 1772 a t the Royal C o l l e g e of P h y s i c i a n s i n London when W i l l i a m Heberden d e l i v e r e d a paper on the chest p a i n a s s o c i a t e d w i t h d i s e a s e of the h e a r t : angina p e c t o r i s . He d e s c r i b e d i t as: "a p a i n f u l and most d i s a g r e e a b l e s e n s a t i o n i n the b r e a s t , which seems as i f i t would e x t i n g u i s h l i f e i f i t were to i n c r e a s e or c o n t i n u e " ( G r o t t o , 1985, p . 8 ) . 'Angina' comes from the Greek word 'angere' which means to s t r a n g l e or s u f f o c a t e ( S h i l l i n g f o r d , 1981). Angina a r i s e s when oxygen demand exceeds the oxygen s u p p l i e d due to inadequate c i r c u l a t i o n caused by narrowing of the a r t e r i e s of the h e a r t . I t occurs more f r e q u e n t l y w i t h e x e r t i o n i n persons w i t h coronary h e a r t d i s e a s e and may be r e l i e v e d by r e s t . A c l a s s i c a l symptom of angina i s a t i g h t or squeezing c e n t r a l chest p a i n , f r e q u e n t l y r a d i a t i n g to the l e f t arm, s h o u l d e r , or neck. Severe narrowing of the coronary v e s s e l s i s g e n e r a l l y the cause of death or damage to the h e a r t muscle known as 'myocardial 26 i n f a r c t i o n ' . Narrowing of the v e s s e l s i s termed a ' s t e n o s i s ' . A m y o c a r d i a l i n f a r c t i o n i s now b e l i e v e d to be due to the forma- t i o n of a c l o t on the w a l l of a c o r o n a r y a r t e r y where s t e n o s i s i s p r e s e n t . P a i n i s not always a s s o c i a t e d w i t h a m y o c a r d i a l i n f a r c t i o n , and damage to the h e a r t muscle can occur as ' s i l e n t i s c h e m i a ' (Shea e t . a l . , 1985). In 1778 Edward Jenner d i s c o v e r e d the r e l a t i o n s h i p between angina p e c t o r i s and the u n d e r l y i n g cause: d i s e a s e of the c o r o n a r y a r t e r i e s . In 1793 Jenner a n a t o m i c a l l y d e f i n e d the d i s e a s e d areas of the a r t e r i e s as 'coronary atheroma' d u r i n g autopsy s t u d i e s . I t was not u n t i l the next c e n t u r y t h a t Antonio Scarpa d e s c r i b e d the p a thogenesis of the c o r o n a r y v e s s e l s as a c o n d i t i o n of u l c e r a t i o n and d e g e n e r a t i o n of the a r t e r i a l l i n i n g . Scarpa was c o r r e c t i n t h i n k i n g t h a t the process took many y e a r s . In 1883 Scarpa's d e s c r i p t i o n was named ' a r t e r i o s c l e r o s i s ' , by J e a n - F r e d - e r i c k L o b s t e i n , a p a t h o l o g i s t . T h i s g e n e r i c term now covers a v a r i e t y of c o n d i t i o n s t h a t cause the a r t e r y w a l l s to l o s e e l a s t i c i t y and t h i c k e n or harden. The term ' a t h e r o s c l e r o s i s ' , d e s c r i b i n g the k i n d of a r t e r i o - s c l e r o s i s of the i n n e r l i n i n g of the a r t e r y , was c o i n e d by another p a t h o l o g i s t , Marchand, i n 1904. A t h e r o s c l e r o s i s i s the r e s u l t of f a t t y d e p o s i t s c a l l e d 'atheromata' (from Jenner's term atheroma) which cause the a r t e r y l i n i n g to become i r r e g u l a r and t h i c k . 27 In 1912 the J o u r n a l of the American M e d i c a l A s s o c i a t i o n p u b l i s h e d " C l i n i c a l F e a t u r e s of Sudden O b s t r u c t i o n of the Coronary A r t e r i e s " by James H e r r i c k . In t h i s a r t i c l e , H e r r i c k i s the f i r s t to d e s c r i b e how o b s t r u c t i o n of the coro n a r y a r t e r i e s can cause the che s t p a i n we c a l l a n g i n a , and m y o c a r d i a l i n f a r c - t i o n (heart a t t a c k ) t h a t causes sudden death i n some persons ( G r o t t o , 1985). A number of complex and sometimes i n t e r r e l a t e d r i s k f a c t o r s are b e l i e v e d to i n f l u e n c e the development of coro n a r y h e a r t d i s e a s e . Some of these f a c t o r s are l i f e - s t y l e r e l a t e d : smoking, o b e s i t y , s e d e n t a r y l i v i n g , and s t r e s s . H e r e d i t y i s a l s o an acknowledged f a c t o r as are c h r o n i c c o n d i t i o n s such as d i a b e t e s and h y p e r t e n s i o n . 2.1 Grading the Angina of Coronary Heart D i s e a s e Coronary h e a r t d i s e a s e i s caused by a t h e r o s c l e r o s i s : a t h i c k e n i n g of the i n t e r i o r l i n i n g of the a r t e r i e s . T h i s a t h e r o - s c l e r o s i s of the v e s s e l s of the h e a r t i s not always symptomatic. I f the bloo d s u p p l y to the h e a r t i s adequate to m a i n t a i n s u f f i - c i e n t oxygen, no p a i n i s a s s o c i a t e d w i t h the narrowing of the v e s s e l s . However, when the o c c l u s i o n c l o s e s the v e s s e l to 30% of i t s i n i t i a l c a p a c i a t y , angina p a i n may o c c u r . Angina, or angina p e c t o r i s , i s o n l y one of a number of common symptoms of coro n a r y h e a r t d i s e a s e . Other symptoms i n c l u d e s h o r t n e s s of b r e a t h and f a t i g u e . Angina can be c l a s s i - 28 f i e d by a number of systems. The grades l i s t e d i n Table 1.1 were e s t a b l i s h e d by the Canadian C a r d i o v a s c u l a r S o c i e t y (1972) and are r e c o g n i z e d by the American N a t i o n a l Heart and Lung I n s t i t u t e . TABLE 1.1 Grading of Angina of E f f o r t by the Canadian C a r d i o v a s c u l a r S o c i e t y 1. " O r d i n a r y p h y s i c a l a c t i v i t y does not cause ... angina", such as w a l k i n g or c l i m b i n g s t a i r s . Angina w i t h strenuous or r a p i d or prolonged e x e r t i o n at work or r e c r e a t i o n . 2. " S l i g h t l i m i t a t i o n of o r d i n a r y a c t i v i t y . " Walking or c l i m b i n g s t a i r s r a p i d l y , w a l k i n g u p h i l l , w a l k i n g or s t a i r c l i m b i n g a f t e r meals, or i n c o l d , or i n wind, or under emotional s t r e s s , or o n l y d u r i n g the few hours a f t e r awakening. Walking more than two b l o c k s on the l e v e l and c l i m b i n g more than one f l i g h t of o r d i n a r y s t a i r s at a normal pace and i n normal c o n d i t i o n s . 3. "Marked l i m i t a t i o n of o r d i n a r y p h y s i c a l a c t i v i t y . " Walking one to two b l o c k s on the l e v e l and c l i m b i n g one f l i g h t of s t a i r s i n normal c o n d i t i o n s and at a normal pace. 4. " I n a b i l i t y to c a r r y on any p h y s i c a l a c t i v i t y without discom- f o r t - a n g i n a l syndrome 'may' be p r e s e n t at r e s t . " SOURCE: Canadian Me d i c a l A s s o c i a t i o n J o u r n a l (1975, vol.122, p. 522) 2.2. The Epidemiology of Coronary Heart D i s e a s e Coronary h e a r t d i s e a s e i s the l e a d i n g cause of death i n Canada and the United S t a t e s . I t i s a p r o g r e s s i v e d i s e a s e t h a t a f f e c t s p r i m a r i l y o l d e r age groups and f r e q u e n t l y a f f e c t s the 29 middle aged. In Western c o u n t r i e s , i t accounts f o r about 80% of a l l the sudden deaths and f o r twice as many deaths as a l l forms of c a n c e r . Although the i n c i d e n c e of co r o n a r y h e a r t d i s e a s e appears to be on the d e c l i n e i n Canada and the United S t a t e s , i t i s one of the major causes of death i n the t w e n t i e t h c e n t u r y ( S h i l l i n g f o r d , 1981). S t a t i s t i c s Canada r e p o r t s t h a t f o r 1982, t h i s type of heart d i s e a s e was the cause of death f o r 28,796 men and 20,239 women ( S t a t i s t i c s Canada, r e p o r t 84-203, 1984) . S t a t i s t i c s on h o s p i t a l s e p a r a t i o n s by d i a g n o s i s i d e n t i f y the number of p a t i e n t s t r e a t e d f o r h e a r t d i s e a s e and the average l e n g t h of s t a y f o r Canadian men and women f o r 1978. F i v e diagnoses were s e l e c t e d and are summarized i n Tabl e 1.2 (u s i n g the I n t e r n a t i o n a l C l a s s i f i c a t i o n of Disease) to i n d i c a t e the economic importance of treatment f o r h e a r t d i s e a s e i n t h i s c o u n t r y . Four diagnoses were s e l e c t e d from the Canadian C l a s s i - f i c a t i o n of D i s e a s e f o r 1982 and are pres e n t e d i n summary form i n Table 1.3. H o s p i t a l data do not i n d i c a t e s e p a r a t i o n s made due to death, but the m o r t a l i t y a s s o c i a t e d w i t h a h o s p i t a l s t a y f o r acute m y o c a r d i a l i n f a r c t i o n ranges from 20% to 30% of p a t i e n t s i n h o s p i t a l (Acton, 1973). As a r e s u l t , combining m o r t a l i t y data and h o s p i t a l s e p a r a t i o n data w i l l tend to o v e r s t a t e the i n c i d e n c e of h e a r t d i s e a s e . In a d d i t i o n , i t i s u s e f u l to note t h a t the d i a g n o s i s of angina causes u t i l i z a t i o n of h o s p i t a l c a r e by about 18,000 p a t i e n t s , but t h i s d i a g n o s i s i s seldom l i s t e d as a cause of d e a t h . 30 TABLE 1.2 H o s p i t a l Stays f o r Canadians w i t h Heart D i s e a s e , per 100,000 P o p u l a t i o n , 1978 (usin g the I n t e r n a t i o n a l C l a s s i f i c a t i o n of Disease) ICDA DIAGNOSIS 410 acute m y o c a r d i a l i n f a r c t i o n 411 ot h e r forms of ischemic7 h e a r t d i s e a s e 412 c h r o n i c h e a r t d i s e a s e 413 angina 427 symptomatic h e a r t d i s e a s e MEN (no.) DAYS6 WOMEN (no.) DAYS 31,280 15.5 14,379 19.8 8,961 10.2 5,948 13.0 36,892 14.5 23,741 24.7 10,446 7.9 7,453 9.3 25,186 12.8 22,799 15.3 NOTE: Many other diagnoses are l i s t e d , o n l y f i v e c a t e g o r i e s are i n c l u d e d i n the t a b l e as an i l l u s t r a t i o n . SOURCE: S t a t i s t i c s Canada (1984, B u l l e t i n 84-203, p. 87-89) 6 Days r e f e r s to the average s t a y i n days per p a t i e n t . 7 Ischemia means damage to the heart muscle caused by inadequate oxygen s u p p l y due to c o n s t r i c t i o n of the co r o n a r y a r t e r i e s . 31 TABLE 1.3 H o s p i t a l Stays f o r Canadians wi t h Heart D i s e a s e , per 100,000 P o p u l a t i o n , 1980-1981 (u s i n g the Canadian C l a s s i f i c a t i o n of Disease) CCL DIAGNOSIS MEN (no.) DAYS WOMEN (no.) DAYS 082 h y p e r t e n s i v e d i s e a s e 7,670 14.4 11,771 15.4 083 acute m y o c a r d i a l i n f a r c t i o n 32,983 15.1 15,680 20.4 084 ot h e r forms of i s c h e m i c h e a r t d i s e a s e 55,816 12.7 36,137 22.5 086 othe r forms of h e a r t d i s e a s e 40,543 15.5 34,878 23.1 NOTE: T h i s c l a s s i f i c a t i o n d i f f e r s from T a b l e 1.2, making compari- son by years i m p o s s i b l e . Where the diagnoses are c o n s i s t e n t , numbers of cases per 100,000 p o p u l a t i o n are s i m i l a r . SOURCE: S t a t i s t i c s Canada, M o r b i d i t y Report (1984, p. 122-123) 2.3 The P r o g r e s s i v e Nature of Coronary A r t e r y D i s e a s e Coronary a r t e r y d i s e a s e i s c o n s i d e r e d to be a p r o g r e s s i v e d i s e a s e i n most p a t i e n t s (Moise and Bourassa, 1985) . In a study of the p r o g n o s t i c s i g n i f i c a n c e of p r o g r e s s i o n of c o r o n a r y d i s e a s e , Moise and Bourassa (1985) examined 313 p a t i e n t s and determined t h a t 139 had p r o g r e s s i o n of the d i s e a s e , 33 d i e d 32 d u r i n g the study p e r i o d , and 39 s u f f e r e d an acute m y o c a r d i a l i n f a r c t i o n but s u r v i v e d . In t o t a l , 211 (63%) p a t i e n t s had more s e r i o u s (or f a t a l ) d i s e a s e a t the end of the s t u d y p e r i o d . These authors a l s o s t a t e d t h a t the combination of p r o g r e s - s i v e d i s e a s e and m y o c a r d i a l i n f a r c t i o n s i g n i f i c a n t l y reduced f o u r year s u r v i v a l of p a t i e n t s w i t h the d i s e a s e . For example, the p r o b a b i l i t y of f o u r year s u r v i v a l w i t h a m y o c a r d i a l i n f a r c t i o n f o r p a t i e n t s w i t h n o n - p r o g r e s s i v e d i s e a s e was 89% w h i l e i t was o n l y 73% f o r p a t i e n t s with p r o g r e s s i v e d i s e a s e . When data i n c l u d e d p a t i e n t s without a m y o c a r d i a l i n f a r c t i o n , the p r o b a b i l i t y of s u r v i v i n g f o u r y ears f o r n o n - p r o g r e s s i v e d i s e a s e was 94% w h i l e w i t h p r o g r e s s i v e d i s e a s e i t was 83%.8 Moise e t . a l . (1985) found p r o g r e s s i o n of a r t e r y d i s e a s e i n 16 of 31 p a t i e n t s s t u d i e d w i t h p r e v i o u s l y i d e n t i f i e d minimal a r t e r y d i s e a s e . They a l s o i d e n t i f i e d p r o g r e s s i o n i n 3 of 20 p a t i e n t s w i t h normal coronary a r t e r i e s . F a c t o r s a s s o c i a t e d w i t h the r a t e of t h i s p r o g r e s s i o n were: the number of d i s e a s e d segments of the a r t e r y , the age of the p a t i e n t , the smoking s t a t u s of the p a t i e n t , and the i n i t i a l c h o l e s t e r o l l e v e l . 8 The Gompertz e f f e c t i s an important c o n t r i b u t i n g f a c t o r i n the m o r t a l i t y r a t e s s t a t e d f o r persons w i t h coronary h e a r t d i s e a s e because t h i s s p e c i f i c p o p u l a t i o n i s an ageing one. Gompertz (1825) showed t h a t a f t e r a c e r t a i n age the l i k e l i h o o d of d y i n g i s more a f u n c t i o n of age than d i s e a s e ; ageing i t s e l f becomes a c r i t i c a l f a c t o r i n r e p o r t e d m o r t a l i t y r a t e s . 33 2.4. The C l i n i c a l Background: M e d i c a l Therapy In the f o l l o w i n g s e c t i o n s on a l t e r n a t i v e treatments f o r c o r o n a r y h e a r t d i s e a s e , the focus i s on angina as a major symptom because i t i s one of the most important s i g n s of treatment e f f e c t i v e n e s s . C o n t r o l of c h e s t p a i n i s a common go a l f o r p a t i e n t s s e e k i n g treatment f o r c o r o n a r y h e a r t d i s e a s e and i t was a key symptom i n the p r e s e n t study. Angina can o f t e n be managed by r e d u c i n g a c t i v i t i e s t h a t aggravate i t such as smoking, o v e r e a t i n g , p h g y s i c a l a c t i v i t y and s t r e s s . In a d d i t i o n to some l i f e s t y l e m o d i f i c a t i o n , m e d i c a l therapy g e n e r a l l y i n v o l v e s one or more of t h r e e groups of drugs. The f i r s t drugs i n g e n e r a l use were the n i t r a t e group, of which g l y c e r y l t r i n i t r a t e i s the most common. The n i t r a t e s a c t to r e l a x the c o r o n a r y a r t e r i e s and i n c r e a s e the blood s u p p l y to the h e a r t , thus r e d u c i n g p a i n . N i t r a t e s a l s o d i l a t e normal a r t e r i e s t h a t s u p p l y o t h e r areas than the h e a r t r e d u c i n g blood volume i n the h e a r t i t s e l f which i n t u r n reduces s t r e t c h i n g of the h e a r t and i t s v e s s e l s . The second group of drugs, b e t a - b l o c k e r s , a c t to r e g u l a t e h e a r t r a t e and the f o r c e of muscle c o n t r a c t i o n by b l o c k i n g the sympathetic nerve t r a n s m i s s i o n to the h e a r t muscle. P a t i e n t s w i t h angina demonstrate s i g n i f i c a n t improvements i n e x e r c i s e t o l e r a n c e when they are t r e a t e d w i t h b e t a - b l o c k e r s . The most w i d e l y used of t h i s group i s p r o p a n o l o l which became a v a i l a b l e i n Canada i n 1970 but was not w i d e l y used u n t i l f i v e years l a t e r (Myers, 1985). 34 The t h i r d group i s the c a l c i u m a n t a g o n i s t s ( a l s o c a l l e d c a l c i u m channel b l o c k e r s ) which have s e v e r a l c a r d i a c a c t i o n s i n c l u d i n g r e l a x i n g ( d i l a t i n g ) c o r o n a r y a r t e r i e s and d e c r e a s i n g the f o r c e of h e a r t muscle c o n t r a c t i o n . They may be used alone or i n c o n j u n c t i o n w i t h b e t a - b l o c k e r s and/or n i t r a t e s . Few s t u d i e s a re a v a i l a b l e to compare the e f f i c a c y of these groups of drugs, e i t h e r alone or i n combination. Those s t u d i e s t h a t have attempted to compare outcomes have used s m a l l sample s i z e s and t h e r f o r e cannot d e t e c t s m a l l d i f f e r e n c e s (Myers, 1985). M e d i c a l treatment can r e l i e v e angina f o r about 70% of p a t i e n t s w i t h c o r o n a r y h e a r t d i s e a s e . Some p a t i e n t s are t r o u b l e d by the s i d e e f f e c t s of the drugs such as drowsiness, impotence, p e r s o n a l i t y changes and nausea, so p a t i e n t compliance can be a management problem. S u r g i c a l treatment of the bloc k e d v e s s e l s i n the h e a r t i s an a l t e r n a t i v e f o r the 30% of p a t i e n t s who do not e x p e r i e n c e p a i n r e l i e f from, or who are not compliant w i t h drug treatment ( S h e l l i n g f o r d , 1981). C a l i f f e t . a l . (1984) have s t a t e d t h a t m e d i c a l therapy f o r p a t i e n t s with coronary h e a r t d i s e a s e may demonstrate a lower s u r v i v a l r a t e than s u r g i c a l treatment because more h i g h r i s k p a t i e n t s are t r e a t e d m e d i c a l l y . These authors r e p o r t e d t h a t ..."reasons f o r s e l e c t i o n of n o n - s u r g i c a l therapy i n c l u d e p a t i e n t and p h y s i c i a n p r e f e r e n c e , concomitant i l l n e s s , and es t i m a t e d s u r g i c a l r i s k " ( C a l i f f e t . a l . , 1984, p.1494). 35 2.5. The C l i n i c a l Background: Coronary Bypass Surgery Coronary A r t e r y Bypass G r a f t i n g (CABG) i s the s u r g i c a l i n t e r p o s i t i o n of a v e i n g r a f t around c o r o n a r y a r t e r i e s b l o c k e d by a t h e r o s c l e r o s i s . The venous homografts are taken from the p a t i e n t ' s l e g s . During t h i s procedure the p a t i e n t ' s body temperature i s reduced, the h e a r t i s a r r e s t e d and c i r c u l a t i o n i s maintained by a mechanical pump t h a t takes the p l a c e of the h e a r t and the l u n g s . CABG i s u s u a l l y a v a i l a b l e to low r i s k p a t i e n t s l e s s than 70 years o l d wi t h good h e a r t f u n c t i o n and no other adverse d i s e a s e s . About 80% to 90% of p a t i e n t s who r e c e i v e a g r a f t have improved angina s t a t u s (Pauker, 1976; Reeder e t . a l . , 1984). S u r g i c a l treatment of angina does not appear to s i g n i f i c a n t l y a l t e r the course of a t h e r o s c l e r o s i s nor i s t h e r e agreement on whether i t a l t e r s the subsequent r i s k of m y o c a r d i a l i n f a r c t i o n (Hamilton e t . a l . , 1983). In the case of l e f t main coronary a r t e r y s t e n o s i s , s t u d i e s have shown prolonged s u r v i v a l i n p a t i e n t s who have had CABG (Alderman, e t . a l . , 1983). Increased s u r v i v a l of p a t i e n t s w i t h t r i p l e v e s s e l d i s e a s e has been demonstrated i n the European Coronary Surgery Study Group (1980) . A major c l i n i c a l t r i a l of c o r o n a r y a r t e r y bypass g r a f t i n g was completed i n 1983. The Coronary A r t e r y Surgery Study (CASS) r e p o r t e d t h a t : "bypass s u r g e r y i s no more e f f e c t i v e than conven- t i o n a l m e d i c a l management i n p r o l o n g i n g s u r v i v a l among p a t i e n t s 36 with s t a b l e i s c h e m i c h e a r t d i s e a s e . " (The M e d i c a l Post, Nov. 27, 1984, p.8) T h i s study (sponsored by the N a t i o n a l Heart, Lung, and Blood I n s t i t u t e ) e s t a b l i s h e d a r e g i s t r y f o r 25,000 p a t i e n t s who demonstrated blockage of one or more coronary a r t e r i e s . The study found the f o l l o w i n g s i g n i f i c a n t f a c t s : f i r s t , the s u r g i c a l m o r t a l i t y r a t e of 6630 p a t i e n t s f o l l o w e d i n the CASS study from 1975 to 1978 was 2.3% w h i l e the r a t e f o r p a t i e n t s over 70 years of age rose to 7.9%; second, the t h r e e month m o r t a l i t y of p a t i e n t s a c r o s s i n s t i t u t i o n s p e r f o r m i n g s u r g e r y ranged from 0.3% to 6.4%; t h i r d , the f i v e year s u r v i v a l r a t e was 89%; and f o u r t h , the m o r t a l i t y curves f o r s u r g i c a l and m e d i c a l groups were almost superimposable (Braunwald,. 1984). Increased e x p e r i e n c e of s u r g i c a l teams w i t h the t e c h n i q u e seemed to be r e l a t e d to lower death r a t e s of p a t i e n t s (Pauker, 1976). The CASS study a l s o determined b a s e l i n e r a t e s of s u r v i v a l f o r 586 men who recovered from a m y o c a r d i a l i n f a r c t i o n but d i d not have CABG. E i g h t y per cent of p a t i e n t s s u r v i v e d 5 y e a r s ; 61% s u r v i v e d 10 y e a r s ; and 43% s u r v i v e d 15 years (Braunwald, 1984). Braunwald (1984) has concluded t h a t a m a j o r i t y of cases s e l e c t e d f o r CABG i n the 1970's had angina of grades t h r e e and f o u r . However, the t r e n d f o r the 1980's has been toward opera- t i n g on l e s s severe c a s e s . In a d d i t i o n , the average age of p a t i e n t s i n t h i s l a t t e r group i s about 50, a p p r o x i m a t e l y h a l f of whom have had a m y o c a r d i a l i n f a r c t i o n . As a r e s u l t of t h i s change i n s u r g i c a l c r i t e r i a , outcome data from the 1970's i s 37 d i f f i c u l t to compare to t h a t of the 1980's. Some c o n t r o v e r s y over the r e l a t i v e m e r i t s of c o r o n a r y bypass g r a f t i n g has emerged i n the m e d i c a l l i t e r a t u r e , w i t h long term s t u d i e s demonstrating e i t h e r no advantage of the s u r g i c a l treatment over the m e d i c a l treatment, or o n l y a s l i g h t advantage. F r i c k e t . a l (1983) conducted a p r o s p e c t i v e study of a randomized s e r i e s of p a t i e n t s w i t h c o r o n a r y a r t e r y d i s e a s e . In one group, 36 p a t i e n t s w i t h s t a b l e angina p e c t o r i s were m e d i c a l l y t r e a t e d w h i l e the other group of 42 p a t i e n t s w i t h s i m i l a r symptoms were s u r g i c a l l y t r e a t e d . A f t e r a f i v e - y e a r f o l l o w - u p 67% of the m e d i c a l and 69% of the. s u r g i c a l l y t r e a t e d p a t i e n t s demonstrated p r o g r e s s i o n of t h e i r h e a r t d i s e a s e . Fewer m e d i c a l l y t r e a t e d p a t i e n t s had complete o c c l u s i o n of a major v e s s e l than d i d s u r g i c a l l y t r e a t e d p a t i e n t s . In another study w i t h s i m i l a r methodology, Detre e t . a l . (1984) r e p o r t e d f o l l o w - u p r e s u l t s of a randomized c o n t r o l l e d t r i a l of p a t i e n t s from the Veterans A d m i n i s t r a t i o n C o o p e r a t i v e Study of CABG. The e f f e c t s of m e d i c a l therapy were compared to medical p l u s s u r g i c a l therapy f o r p a t i e n t s w i t h s t a b l e a n g i n a . T h i s study determined t h a t over a f i v e - y e a r p e r i o d , therapy had l i t t l e e f f e c t on r e s t i n g l e f t v e n t r i c u l a r f u n c t i o n among s u r v i - vors i n e i t h e r group. A number of p a t i e n t s d i e d of m y o c a r d i a l i n f a r c t i o n d u r i n g the study. In a d d i t i o n to the c o n t r o v e r s y over the f i n d i n g s of these s t u d i e s , c o n t r o v e r s y e x i s t s over the problems c r e a t e d by random- 38 i z e d c l i n i c a l t r i a l s . Rahimtoola (1985) has s t a t e d t h a t these s t u d i e s a r e f r a u g h t with problems i n c l u d i n g : p o s s e s s i o n of the data by the s p o n s o r i n g i n d u s t r y , drawing the wrong c o n c l u s i o n s from the i n i t i a l h y p o t h e s i s , continuous a l t e r a t i o n of the h y p o t h e s i s , e x c l u s i o n of many of the e l i g i b l e p a t i e n t s , s i g n i f i - cant c r o s s o v e r of p a t i e n t s , and sample s i z e s too s m a l l f o r comparison. 2.6. The C l i n i c a l Background: A n g i o p l a s t y A more r e c e n t i n n o v a t i o n i n the treatment of co r o n a r y a r t e r y d i s e a s e i s Percutaneous T r a n s l u m i n a l Coronary A n g i o p l a s t y (PTCA). Coronary a n g i o p l a s t y i s a n o n - s u r g i c a l method of r e d u c i n g the s t e n o s i s i n a co r o n a r y a r t e r y u s i n g a d i l a t i n g c a t h e t e r equipped with a guide w i r e and a s m a l l i n f l a t a b l e b a l l o o n . The b a l l o o n i s i n f l a t e d i n s i d e a p a r t i a l l y b l o c k e d c o r o n a r y a r t e r y to d i s l o d g e or compress the a t h e r o s c l e r o t i c plaque i n the v e s s e l . The c a t h e t e r r o u t e used i s u s u a l l y femoral (the a r t e r y i n the p a t i e n t ' s leg) but may a l s o be b r a c h i a l (from the arm). During the i n f l a t i o n of the b a l l o o n , the coro n a r y a r t e r y w i l l be c o m p l e t e l y b l o c k e d which may cause severe angina or my o c a r d i a l i n f a r c t i o n . S u r g i c a l i n t e r v e n t i o n i n the form of CABG i s always a p o s s i b i l i t y f o r p a t i e n t s who e l e c t a n g i o p l a s t y . The c o n t r o l l e d i n j u r y to the coronary v e s s e l h e a l s s l o w l y , a l t h o u g h the p a t i e n t can u s u a l l y r e t u r n to normal a c t i v i t y w i t h i n a week. 39 There are a number of advantages to the s h o r t e r h o s p i t a l i z a t i o n r e q u i r e d f o r PTCA i n c l u d i n g improved chances of the p a t i e n t r e t u r n i n g to work. Amiel e t . a l . (1984) e s t i m a t e t h a t 5% to 10% of p a t i e n t s p r e v i o u s l y t r e a t e d by CABG can be t r e a t e d w i t h a n g i o p l a s t y . The treatment i s c o n s i d e r e d to be s u c c e s s f u l i f the s t e n o s i s i s decreased by 20%. In a s t u d y r e p o r t e d by G r e u n t z i g e t . a l . (1979), i n i t i a l s uccess (measured as r e l i e f from angina) was 66%, emergency bypass s u r g e r y was r e q u i r e d f o r 12% of the p a t i e n t s , and no deaths were a t t r i b u t a b l e to a n g i o p l a s t y . T h i s study f o l l o w e d 33 p a t i e n t s f o r a mean of 9 months and found 25 had improved ( l e s s a n g i n a ) , 6 d e t e r i o r a t e d and 2 d i e d ( G r e u n t z i g e t . a l . , 1979). In a N a t i o n a l Heart Lung and Blood I n s t i t u t e study, 34 major c e n t r e s u s i n g a n g i o p l a s t y r e p o r t e d a success r a t e of 59% f o r 663 treatments on 631 p a t i e n t s ( L e v i , e t . a l . , 1981). The m o r t a l i t y r a t e from subsequent s u r g e r y due to f a i l e d a n g i o p l a s t y was 0.95%. C o m p l i c a t i o n s i n the method caused f a i l u r e i n 18.5% of the p a t i e n t s . By 1983, a f i v e year r e p o r t from the same I n s t i t u t e showed 73 c e n t r e s r e p o r t i n g on 1,500 p a t i e n t s . The r a t e of emergency CABG due to o c c u l s i o n of the c o r o n a r y a r t e r y d u r i n g PTCA was 6.8% with a m o r t a l i t y r a t e of 1.1% due to a n g i o p l a s t y i t s e l f . The i n c i - dence of c o m p l i c a t i o n s t h a t produced severe m y o c a r d i a l ischemia 40 or i n f a r c t i o n or death was r e p o r t e d to be n e a r l y t h a t of CABG ( G r e u n t z i g , 1983). Braunwald (1984) s t a t e s t h a t 60% to 80% of cases of PTCA show a s u c c e s s f u l d i l a t i o n of the s t e n o s i s . In 5% of the cas e s , the c o r o n a r y a r t e r y o c c l u s i o n produced by the equipment causes a my o c a r d i a l i n f a r c t i o n . Risk of death f o r t h i s group can be reduced by doing a CABG immediately. M o r t a l i t y o v e r a l l i n t h i s procedure i s s t a t e d as 0.5% to 1%. In about 20% of i n i t i a l l y s u c c e s s f u l c a s e s , r e s t e n o s i s occurs w i t h i n s i x months. About t w o - t h i r d s of t h i s group can have the procedure repeated s u c c e s s - f u l l y . I t has been e s t i m a t e d t h a t 15% to 30% of p a t i e n t s e l i g i b l e f o r CABG may be e f f e c t i v e l y t r e a t e d by PTCA (Marquis, 1985). (Note t h a t t h i s i s twice as hig h as the Amiel e t . a l . e s - t imate) A n g i o p l a s t y has a range of r i s k s and r e s u l t s important to the p r e p a r a t i o n of any t o o l f o r e l i c i t i n g p a t i e n t p r e f e r e n c e s f o r t h i s type of treatment. Research r e p o r t e d above i n d i c a t e s an i n i t i a l s uccess r a t e of 60% to 80%. Of t h i s p a t i e n t group, 80% have long term f u n c t i o n a l improvement and reduced angina w h i l e 15% to 20% have e a r l y r e s t e n o s i s . The r i s k s a r e : 10% of p a t i e n t s have t o t a l c o r o n a r y o c c l u s i o n , 5% to 10% s u f f e r a m y o c a r d i a l i n f a r c t i o n , 5% to 10% must have an emergency bypass when a n g i o p l a s t y f a i l s , and about 2% of p a t i e n t s s u f f e r h o s p i t a l deaths. These groups are not m u t u a l l y e x c l u s i v e . 41 2.7. The Cost of M e d i c a l Therapy i n Canada Many p a t i e n t s w i t h angina are t r e a t e d throughout the remainder of t h e i r l i v e s with l a r g e doses of a b e t a - b l o c k e r , a c a l c i u m - c h a n n e l b l o c k e r and a l o n g - a c t i n g n i t r a t e i n order to c o n t r o l t h e i r symptoms (Waters, 1985). A segment of the Waters (1985) study i s reproduced i n T a b l e 1.4 to i n d i c a t e the average c o s t i n Canada f o r one month of treatment with drugs t h a t prevent a n g i n a . A p a t i e n t u s i n g each of the t h r e e types of drugs d e s c r i b e d above c o u l d be p a y i n g $145.00 a month f o r treatment (Waters, 1985). The data r e p r e s e n t averages c a l c u l a t e d from a n a t i o n a l survey of pharmacists and h o s p i t a l s i n 1984. TABLE 1.4. Average Cost of A n t i a n g i n a l Drugs i n Canada (1985) Drug Dose (mg/d) Cost per month ($) N i t r a t e I s o s o r b i d e d i n i t r a t e 120 15.92 B e t a - b l o c k e r P r o p a n o l o l 160 19.84 320 29.68 P i n d o l o l 20 29.80 Calcium-Channel B l o c k e r Verapamil 480 73.15 N i f e d i p i n e 80 99.00 SOURCE: Wal t e r s (1985) The Canadian M e d i c a l A s s o c i a t i o n J o u r n a l , vol.171, p. 627 42 8.0 The Cost of Coronary A r t e r y Bypass G r a f t i n g C a t a s t r o p h i c e x p e n d i t u r e s a s s o c i a t e d w i t h s u r g e r y and h o s p i t a l i z a t i o n f o r the c r i t i c a l l y i l l have been documented by a number of authors (Zook and Moore, 1977) . Coronary a r t e r y bypass g r a f t i n g i s c o n s i d e r e d to be among those h i g h c o s t e p i s o d e s . Keon, Menzies and Lay (1985) have i n v e s t i g a t e d the c o s t of CABG at the Ottawa Heart I n s t i t u t e . In 1984, 750 c o r o n a r y a r t e r y g r a f t s were performed at t h i s I n s t i t u t e and 50 of these were randomly s e l e c t e d f o r d e t a i l e d economic a n a l y s i s u s i n g h o s p i t a l c h a r t s . The r a t i o of males to females was 5 to 1, s i m i l a r to the Canadian average f o r i n c i d e n c e of c o r o n a r y h e a r t d i s e a s e c a l c u - l a t e d by Anderson (1973). The mean age was 55.3 with a range of 39 to 73 y e a r s , a l s o near the Canadian average f o r t h i s d i s e a s e . The average c o s t of an episode of care i n v o l v i n g coronary a r t e r y g r a f t i n g was $9595.00 wi t h a range of $6387.00 to $18,415.00 ( i n 1983 d o l l a r s ) . P r o f e s s i o n a l f e e s were 20% to 30% of the t o t a l and h o s p i t a l c o s t s were 70% to 80% of the t o t a l . I n d i r e c t c o s t s were not c o n s i d e r e d , i n c l u d i n g p a t i e n t time away from work, t r a v e l to the h o s p i t a l , r e c o v e r y time at home, and f a m i l y d i s r u p t i o n . In a r e c e n t study of CABG performed i n the U n i t e d S t a t e s , 191,000 cases were es t i m a t e d to have been performed i n 1983 ( M e t r o p o l i t a n L i f e Insurance Co., 1985). During the e a r l y 1980*s the average American me d i c a l care charges f o r a coronary bypass o p e r a t i o n were $21,800 wit h a 228% o v e r a l l v a r i a t i o n by s t a t e . 43 On the average, 71% of the d i r e c t c o s t to the i n s u r e r was a t t r i b u t a b l e to h o s p i t a l c o s t s w h i l e 29% was the p h y s i c i a n ' s f e e . These f e e s v a r i e d a c r o s s s t a t e s from a low of about $5,000 to a hig h of about $10,000. The M e t r o p o l i t a n (1985) study has c o n t r i b u t e d a d e t a i l e d a n a l y s i s of some i n d i r e c t c o s t s a t t r i b u t a b l e to CABG i n the Uni t e d S t a t e s . Between 1974 and 1978, 147 a c t i v e employees of the company underwent CABG. H a l f of the cases recorded o c c u r r e d i n 1977 and 1978 and over h a l f (56%) of the p a t i e n t s were under 55 years of age (44% were between 55 and 64). Two groups of employees emerged i n t h i s a n a l y s i s : those r e t u r n i n g to work and those not r e t u r n i n g . Ninety-one (62%) employees r e t u r n e d to work a f t e r an average of 20 weeks r e c u p e r a - t i n g , a c cumulating 9,000 s i c k days. More employees under 55 re t u r n e d to work than over 55. Of t h i s c o h o r t , o n l y 9 were s t i l l a t work on January 1, 1984. The 56 employees (38%) who d i d not r e t u r n to work accumulated 61,000 s i c k days. The wage l o s s per p a t i e n t averaged $68,000 wit h a range of $40,000 to $108,000. Younger employees who d i d not r e t u r n to work s u f f e r e d the g r e a t e s t wage l o s s even a f t e r s i c k pay and d i s a b i l i t y compensation were taken i n t o account. I t was c l e a r t h a t the i n d i r e c t c o s t s to p a t i e n t s and to employers of p a t i e n t s r e c e i v i n g CABG c o u l d f a r exceed the d i r e c t c o s t s of the episode of s u r g i c a l and h o s p i t a l care r e l a t e d to the bypass o p e r a t i o n . 44 2.9. The Cost of A n g i o p l a s t y The t o t a l h e a l t h care c o s t of a n g i o p l a s t y has been es t i m a t e d to be o n e - f i f t h to o n e - s i x t h as much as bypass s u r g e r y (Amiel e t . a l . , 1984). In a study- at the Mayo C l i n i c , Reeder e t . a l . (1984) have r e p o r t e d a s i g n i f i c a n t (56.1%) d i f f e r e n c e between the c o s t of a n g i o p l a s t y ($7,508) and co r o n a r y bypass s u r g e r y ($13,387) i n c l u d i n g one year f o l l o w - u p . The f o l l o w - u p c o s t s i n c l u d e d the c o s t of coro n a r y bypass s u r g e r y f o r 25% of the a n g i o p l a s t y p a t i e n t s w i t h r e s t e n o s i s . Length of h o s p i t a l s t a y was a l s o s i g n i f i c a n t l y d i f f e r e n t : 9.3 days f o r a n g i o p l a s t y and 13.2 f o r co r o n a r y bypass. Reeder e t . a l . (1984) e s t i m a t e d an 85% success r a t e f o r a n g i o p l a s t y done a t the Mayo C l i n i c a f t e r 1984, w h i l e the success r a t e r e p o r t e d i n the 1980 study group was o n l y 69%. The i n c r e a s e d success r a t e was acknowledged by the authors to cause a r e d u c t i o n i n the c o s t of c a r e f o r the a n g i o p l a s t y group. 2.10. C o n c l u s i o n s from the C l i n i c a l D i s c u s s i o n T h i s s e c t i o n has o u t l i n e d the c l i n i c a l treatment o p t i o n s f o r p a t i e n t s w i t h coronary h e a r t d i s e a s e . The o b j e c t i v e of each treatment i s to reduce the s e v e r i t y of symptoms a s s o c i a t e d with c o r o n a r y h e a r t d i s e a s e and reduce the r i s k of premature death. The p r o b a b i l i t i e s of success as w e l l as the r i s k s have been summarized. S u r g i c a l i n t e r v e n t i o n (CABG) and n o n - s u r g i c a l i n t e r v e n t i o n ( A n g i o p l a s t y ) o f f e r a h i g h e r p r o b a b i l i t y of p a i n 45 r e d u c t i o n accompanied by p e r i - o p e r a t i v e m o r t a l i t y w h i l e medical treatment has a lower p r o b a b i l i t y of r e d u c i n g p a i n but a l s o has a s i g n i f i c a n t l y lower r i s k of e a r l y m o r t a l i t y as a r e s u l t of t reatment. Many f a c t o r s must be c o n s i d e r e d f o r an e f f e c t i v e d e c i s i o n i n the treatment of c o r o n a r y h e a r t d i s e a s e . Some of these f a c t o r s are t e c h n i c a l and d i a g n o s t i c , l i m i t i n g p a r t i c i p a t i o n of the p a t i e n t because of the r a t i o n a l i t y l i m i t a t i o n s i n h e r e n t i n medical p r a c t i c e . However, some f a c t o r s are w e l l w i t h i n the p r e r o g a t i v e of the p a t i e n t , and these i n c l u d e the w i l l i n g n e s s to bear r i s k s and the p r e f e r e n c e f o r outcomes depending on t h e i r p r o b a b i l i t y of o c c u r r e n c e . I t i s t h i s important c o n t r i b u t i o n of the p a t i e n t t h a t was addressed i n the p a t i e n t p r e f e r e n c e study. The summary i n T a b l e 1.5 i d e n t i f i e s the o p p o r t u n i t i e s f o r p a t i e n t s to p a r t i c i p a t e i n the d e c i s i o n to t r e a t coronary a r t e r y d i s e a s e . The outcome p r o b a b i l i t i e s are those d i s c u s s e d i n t h i s s e c t i o n , and the " c o s t s ' l i s t e d r e p r e s e n t both economic c o s t s to s o c i e t y and economic as w e l l as p e r s o n a l c o s t s to the p a t i e n t . TABLE 1.5. Summary of Treatments and Outcomes i n the D e c i s i o n to T r e a t Coronary A r t e r y D i s e a s e . STEP 1 ENTRY TO THE HEALTH SYSTEM a) The p a t i e n t e n t e r s the treatment phase d i r e c t l y due to symptoms: che s t p a i n , s h o r t n e s s of b r e a t h , unwarranted f a t i g u e , or p r o s t r a t i o n due to a h e a r t a t t a c k . 46 b) The p a t i e n t e n t e r s the treatment phase because of i d e n t i f i c a t i o n of s u b c l i n i c a l symptoms by s c r e e n i n g or f o l l o w - u p of other h e a l t h problems. PATIENT DECISION The p a t i e n t d e c i d e s whether to accept e n t r y to the h e a l t h system by a d m i t t i n g or by i g n o r i n g the e f f e c t of symptoms of h e a r t d i s e a s e . D i a g n o s i s of the e x t e n t of a t h e r o s c l e r o s i s or s t e n o s i s of the coronary v e s s e l s i s a c h i e v e d v i a case h i s t o r y , e l e c t r o c a r d i o g r a m , blood p r e s s u r e measurement, s t r e s s t e s t i n g and d i a g n o s t i c imaging such as an angiogram. PATIENT DECISION The p a t i e n t d e c i d e s how much i n f o r m a t i o n to r e v e a l i n a case h i s t o r y , and d e c i d e s whether the r i s k s a t t a c h e d to d i a g n o s t i c t e s t s are compensated by the v a l u e of the d i a g n o s t i c i n f o r m a t i o n i n choosing an a p p r o p r i a t e treatment. STEP 2 DIAGNOSIS STEP 3 TREATMENT OPTIONS PROBABILITIES of OUTCOMES a)m e d i c a l management 60% to 80% chance of no p a i n , 20% to 40% chance of same symptoms, l i k e l y s i d e e f f e c t s such as nausea. b)co r o n a r y bypass 60% chance of no p a i n , 80% chance of some p a i n r e l i e f , 1% to 10% r i s k of death, 15% to 25% chance of same p a i n . c ) a n g i o p l a s t y undetermined long term outcome, s h o r t term: 60% to 80% chance of p a i n r e l i e f , 1% to 5% r i s k of death, 15% to 20% chance of no r e l i e f . d ) l i f e s t y l e change no data a v a i l a b l e . e)do n o t h i n g d i s e a s e p r o g r e s s e s , p a i n l i k e l y to remain. 47 PATIENT DECISION The p a t i e n t e v a l u a t e s the p r o b a b i l i t i e s of outcomes and s e l e c t s the treatment whose outcome most c l o s e l y meets h i s / h e r p r e f e r e n c e s . STEP 4 PHYSICIAN PREFERENCES P h y s i c i a n s b e n e f i t e c o n o m i c a l l y from the i n i t i a t i o n of treatment o p t i o n s a, b, and c. The h e a l t h system reimburses p h y s i c i a n s f o r d i a g n o s t i c p r o c e d u r e s , o f f i c e v i s i t s , and s u r g i c a l i n t e r v e n t i o n s . STEP 5 ECONOMIC IMPACT and SOCIAL PREFERENCES ECONOMIC IMPACT COST TO PATIENT a) m e d i c a l management -drugs $140.00 per month - s i d e e f f e c t s of drugs b) c o r o n a r y bypass s u r g e r y - l a r g e work l o s s - m o r b i d i t y (10-24 days) - r i s k of death - p r o f i t s f o r drug companies - c o s t s of p h y s i c i a n care - c o s t of s u r g e r y i s $13,000 - c o s t s of p h y s i c i a n care c) a n g i o p l a s t y - s m a l l work l o s s - m o r b i d i t y (4-10 days) - r i s k of death d) l i f e s t y l e change - p e r s o n a l e f f o r t e) do no t h i n g - u n c e r t a i n t y about f u t u r e h e a l t h -treatment c o s t i s $7,000 -reduced tobacco s a l e s , e t c . -premature l o s s of l i f e PATIENT DECISION The p a t i e n t determines whether the p e r s o n a l c o s t s of a treatment a l t e r the s t e p 3 c h o i c e of a treatment due the m e r i t s of i t s outcomes i n terms of the p a t i e n t ' s h e a l t h . SOCIAL CHOICE S o c i e t y determines the p r o p o r t i o n of h e a l t h care r e s o u r c e s t h a t w i l l be made a v a i l a b l e f o r treatment of co r o n a r y a r t e r y d i s e a s e . 48 2.11. The Research Questions The r e s e a r c h q u e s t i o n s were based on the premise t h a t p a t i e n t p r e f e r e n c e s ought to matter. The o p t i o n s a v a i l a b l e to most p a t i e n t s have been d e s c r i b e d and the r e s e a r c h q u e s t i o n s developed have used the p r o b a b i l i t i e s of outcomes as o u t l i n e d i n t h i s s e c t i o n . The l i t e r a t u r e r e p o r t i n g p r e v i o u s r e s e a r c h f i n d i n g s i n the study of p a t i e n t p r e f e r e n c e s and d e c i s i o n making behaviour i s reviewed i n c h a p t e r s 3 and 4. T h i s l i t e r a t u r e has shown t h a t when p a t i e n t s are asked to express a p r e f e r e n c e , t h i s p r e f e r e n c e i s v u l n e r a b l e to a number of e r r o r s of judgement. The l i t e r a t u r e has a l s o shown t h a t independent v a r i a b l e s have some i n f l u e n c e over the e x p r e s s i o n of a p r e f e r e n c e or c h o i c e . The q u e s t i o n s e x p l o r e d i n t h i s study are d e f i n e d more com p l e t e l y i n l a t e r c h a p t e r s , but are l i s t e d here i n o r d er to complete the i n t r o d u c t o r y f u n c t i o n of t h i s c h a p t e r . The r e s e a r c h q u e s t i o n s a r e : a) P a t i e n t s ' p e r c e p t i o n of the i n f o r m a t i o n p r o v i d e d i s a l t e r e d by the manner i n which the i n f o r m a t i o n i s p r e s e n t e d . b) P a t i e n t s make e r r o r s i n j u d g i n g the p r o p o r t i o n a l d i f f e r e n c e between p a i r s of outcomes. c) The s i z e and p r o b a b i l i t y of a p o t e n t i a l g a i n i n f l u e n c e s the p a t i e n t ' s v a l u e of t h a t g a i n depending on whether the p a t i e n t s must choose between two gains or o f f e r something of value i n exchange f o r those g a i n s . 49 d) A p a t i e n t ' s w i l l i n g n e s s to take a treatment with a r i s k i s i n f l u e n c e d by whether the p a t i e n t views the treatment as a g a i n or a l o s s . e) A ' r i g h t ' a l r e a d y possessed by a p a t i e n t w i l l be worth more to the p a t i e n t than a ' r i g h t ' he/she may want to p o s s e s s . f) The s e v e r i t y of c o r o n a r y a r t e r y d i s e a s e i s a f a c t o r i n p r e d i c t i n g a p a t i e n t ' s w i l l i n g n e s s to take a treatment r i s k . g) P r e f e r e n c e s are i n f l u e n c e d by a p a t i e n t ' s age, the s e v e r i t y of c oronary a r t e r y d i s e a s e , and the p r e v i o u s h e a l t h c a r e h i s t o r y . In the f o l l o w i n g c h a p t e r , methods developed to e x p l o r e p a t i e n t c h o i c e s and p r e f e r e n c e s r e l a t i n g to these r e s e a r c h ques- t i o n s are d e s c r i b e d . 50 CHAPTER 2 MEASURING PATIENT PREFERENCES: Methodology 1 . 0 . I n t r o d u c t i o n T h i s chapter d e a l s w i t h the methodology of the study and the use of the q u e s t i o n n a i r e to e l i c i t p a t i e n t p r e f e r e n c e s f o r outcomes of treatment f o r coro n a r y h e a r t d i s e a s e . The methodology reviewed r e f l e c t s d e c i s i o n making behaviour s t u d i e d i n a v a r i e t y of s e t t i n g s , w i t h emphasis on those t h a t r e l a t e d i r e c t l y to h e a l t h c a r e . Methods a p p l i c a b l e to the purposes of t h i s study i n c l u d e : e l i c i t i n g p r e f e r e n c e s f o r treatments and h o s p i t a l s t a y s , measuring p a t i e n t s ' a v e r s i o n to s u r g i c a l or treatment r i s k , and p a t i e n t s ' w i l l i n g n e s s to pay f o r treatment as a measure of the va l u e of h e a l t h c a r e . Many s t u d i e s of d e c i s i o n making and i n d i v i d u a l s ' p r e f e r e n c e s have used c o l l e g e s t u d e n t s as s u b j e c t s . S t u d i e s of r e a l and h y p o t h e t i c a l r i s k have been reviewed (McNeil e t . a l . , 1978; Grether and P l o t t , 1979; S l o v i c and L i c h t e n s t e i n , 1983). They suggest t h a t some b e n e f i t s a ccrue to a s t r a t e g y of a s k i n g p r e f e r e n c e q u e s t i o n s to p a t i e n t s when we wish to c o n t r i b u t e to an und e r s t a n d i n g of d e c i s i o n s to i n i t i a t e c o s t l y treatments w i t h u n c e r t a i n outcomes. Support f o r the study of r e a l d e c i s i o n s comes from E i n h o r n and Hogarth (1981, p. 81) who s t a t e : "The e x t e r n a l v a l i d i t y of d e c i s i o n making r e s e a r c h t h a t r e l i e s on l a b o r a t o r y s i m u l a t i o n s of r e a l world problems i s low." 51 2.0. S t r u c t u r e of the Chapter T h i s c hapter has f o u r main components: a d i s c u s s i o n of the sample, comments on the c h o i c e of measurement s t r a t e g i e s , a d m i n i s t r a t i o n of the q u e s t i o n n a i r e , and a n a l y s i s of the r e s u l t s . The d i s c u s s i o n of s u b j e c t s i n the study i s comprised of f o u r s e c t i o n s . The f i r s t s e c t i o n p r e s e n t s sampling s t r a t e g y , the c a l i b r a t i o n of s u b j e c t s , the r o l e of the p a t i e n t i n the study, and p a t i e n t a s s u r a n c e . The instrument i t s e l f appears i n Appendix I a l o n g w i t h a p p r o p r i a t e c o v e r i n g l e t t e r s used, the a p p l i c a t i o n to the u n i v e r s i t y e t h i c s committee and the e t h i c s c e r t i f i c a t e , p a t i e n t i n s t r u c t i o n s , and d e b r i e f i n g m a t e r i a l s f o r p a r t i c i - p a n t s . The v i s u a l a i d s used to a s s i s t s u b j e c t s appear i n Appendix I I . S e c t i o n two of the c hapter reviews methods d e s c r i b e d i n the l i t e r a t u r e t h a t have been shown to produce r e l i a b l e r e s u l t s i n d e t e r m i n i n g p a t i e n t p r e f e r e n c e s and d e m o n s t r a t i n g d e c i s i o n making be h a v i o u r . S e c t i o n t h r e e reviews f a c t o r s important i n a c h i e v i n g a c c e p t a b l e r a t e s of response. I n t e r v i e w e r b i a s and s t e p s taken to reduce i t s i n f l u e n c e are a l s o d i s c u s s e d i n t h i s s e c t i o n . The s t a t i s t i c a l procedures and the r a t i o n a l e f o r s e n s i t i v i t y a n a l y s i s of the r e s u l t s comprise the f o u r t h component of the c h a p t e r . 3.0. Sampling S t r a t e g y P a t i e n t s w i t h coronary h e a r t d i s e a s e were s e l e c t e d as s u b j e c t s f o r t h i s study because, as s t a t e d e a r l i e r , h e a r t 52 d i s e a s e i s the l e a d i n g cause of death and a major consumer of h e a l t h care r e s o u r c e s i n Canada. In a d d i t i o n , i n v o l v i n g p a t i e n t s who are s e e k i n g m e d i c a l c a r e p r o v i d e s an o p p o r t u n i t y to study d e c i s i o n making i n a s i t u a t i o n w i t h c o n s i d e r a b l e r e a l i s m i n comparison to the use of s u b j e c t s making h y p o t h e t i c a l c h o i c e s . A student r i s k i n g a d o l l a r i n a c l a s s r o o m s e t t i n g may demonstrate ve r y d i f f e r e n t d e c i s i o n making beha v i o u r s than a p a t i e n t r i s k i n g h i s / h e r own l i f e i n the o p e r a t i n g room (Knetsch and Sinden, 1984; V e r t i n s k y e t . a l . , 1974). The r e s e a r c h p l a n i n v o l v e d a d m i n i s t e r i n g a complete ques- t i o n n a i r e to 65 s u b j e c t s : 15 h e a l t h y a d u l t s and 50 p a t i e n t s b e i n g t r e a t e d f o r h e a r t d i s e a s e by p h y s i c i a n s i n the C a r d i o l o g y D i v i s i o n of the Vancouver Gene r a l H o s p i t a l . A more l i m i t e d q u e s t i o n n a i r e was answered by 37 h o s p i t a l a d m i n i s t r a t o r s i n order to i n c l u d e responses by a d u l t s who were f r e e from d i s a b l i n g h e a r t d i s e a s e . The q u e s t i o n n a i r e was p r e t e s t e d on 14 s u b j e c t s . Ten p a t i e n t s w i t h coronary h e a r t d i s e a s e p a r t i c i p a t e d i n the p r e t e s t - ing of the q u e s t i o n n a i r e and f o u r h e a l t h c a r e p r o f e s s i o n a l s e v a l u a t e d the s k i l l s of the r e s e a r c h e r by completing the ques- t i o n n a i r e . T h i s p r e t e s t i s d i s c u s s e d i n d e t a i n i n s e c t i o n 7.0. A l t o g e t h e r , 115 s u b j e c t s completed a f u l l or l i m i t e d q u e s t i o n - n a i r e . From t h i s t o t a l , 49 p a t i e n t s , 15 h e a l t h y c o n t r o l s u b j e c t s and 37 h o s p i t a l a d m i n i s t r a t o r s formed the f i n a l study group. No p r e t e s t q u e s t i o n n a i r e s were used i n the data a n a l y s i s . 53 The p a t i e n t s with h e a r t d i s e a s e were r e c r u i t e d by s i x c a r d i o l o g i s t s who allowed the p a t i e n t s i n t h e i r p r a c t i s e s to be i n c l u d e d i n the study over a f i v e month p e r i o d . A c t i v e r e c r u i t m e n t of p a t i e n t s by d o c t o r s was the method of p a t i e n t s e l e c t i o n . Even w i t h p h y s i c i a n p a r t i c i p a t i o n , c o n s i d e r a b l e d i f f i c u l t y was encountered i n a c h i e v i n g the t a r g e t number of p a t i e n t s . The 50 p a t i e n t s who agreed to p a r t i c i p a t e were drawn from over 670 p a t i e n t s w i t h scheduled appointments i n the c a r d i o l o g i s t s ' p r a c t i s e s d u r i n g the f i v e months of the study. During t h i s data c o l l e c t i o n phase of the p r o j e c t , the r e s e a r c h e r was r e q u i r e d to be p r e s e n t i n the C a r d i o l o g y D i v i s i o n or i n the group c a r d i o l o g y p r a c t i s e every day d u r i n g o f f i c e hours, and to be a v a i l a b l e to i n t e r v i e w p a t i e n t s at home. The h e a l t h y s u b j e c t s were a d u l t s between the ages of 40 and 65, an age range t y p i c a l of p a t i e n t s w i t h h e a r t d i s e a s e . These s u b j e c t s were r e c r u i t e d by the r e s e a r c h e r u s i n g the membership r o s t e r of the A l t a Lake Sports C l u b . The membership of t h i s o r g a n i z a t i o n i n c l u d e d f a m i l i e s who were a c t i v e i n outdoor r e c r e a - t i o n and s p o r t s . The h o s p i t a l a d m i n i s t r a t o r s p a r t i c i p a t e d i n a s h o r t q u e s t i o n n a i r e as p a r t of a l e c t u r e i n medical d e c i s i o n making g i v e n at the P a c i f i c H e a l t h Forum i n Vancouver i n September, 1985. From an audience of 52 a d m i n i s t r a t o r s , 37 completed q u e s t i o n n a i r e s were r e c e i v e d . Many p a t i e n t s who were approached d e c l i n e d f o r a v a r i e t y of reasons. Some p a t i e n t s f e l t they were too i l l to p a r t i c i p a t e ; 54 some p a t i e n t s f e l t the time commitment was too g r e a t ; one p a t i e n t d i d n ' t l i k e ' r e s e a r c h ' ; and some p a t i e n t s gave no reasons f o r t h e i r r e f u s a l to p a r t i c i p a t e . S e v e r a l p a t i e n t s agreed to p a r t i c i p a t e , but d i d not complete the q u e s t i o n n a i r e . For example, one p a t i e n t w i t h u n s t a b l e angina who agreed to p a r t i c i p a t e became anxious d u r i n g the q u e s t i o n n a i r e and was a d v i s e d by the r e s e a r c h e r to withdraw. One p a t i e n t was m e n t a l l y unable to focus on the q u e s t i o n s ; f o r o t h e r s language was a b a r r i e r a l t h o u g h they were w i l l i n g ; and one p a t i e n t was admitted to h o s p i t a l a f t e r a g r e e i n g to p a r t i c i p a t e but b e f o r e commencing. I f a q u e s t i o n n a i r e was not completed, another p a t i e n t was r e c r u i t e d . The 50 p a t i e n t s d e s c r i b e d above formed the h e a r t study group c o m p r i s i n g t h r e e c a t e g o r i e s . The 'heart d i s e a s e c o n t r o l ' group c o n s i s t e d of 20 p a t i e n t s with asymptomatic c o r o n a r y h e a r t d i s e a s e ( d i s e a s e diagnosed but not showing s i g n s or symptoms), or a r r y t h m i a s ( i r r e g u l a r rhythm of the h e a r t ) t r e a t e d by m e d i c a t i o n or a pacemaker, or w i t h v a l v e d i s e a s e . No p a t i e n t s i n t h i s group e x p e r i e n c e d p a i n d u r i n g the time of the study, a l t h o u g h some had p r e v i o u s l y e x p e r i e n c e d angina p a i n . The c o r o n a r y h e a r t d i s e a s e p a t i e n t s w i t h angina p a i n were c l a s s i f i e d i n t o two groups: the group wi t h 'mild angina' con- t a i n e d 15 p a t i e n t s , and the group w i t h 'severe angina' c o n t a i n e d 15 p a t i e n t s , of whom 14 p a t i e n t s completed a u s a b l e q u e s t i o n - n a i r e . The unusable q u e s t i o n n a i r e from t h i s group was not 55 r e p l a c e d , as the r e s e a r c h e r had determined a f t e r the completion of the data c o l l e c t i o n t h a t t h i s p a t i e n t s h o u l d be e x c l u d e d . The reason f o r e x c l u s i o n was t h a t t h i s p a t i e n t was the o n l y p a t i e n t i n t e r v i e w e d i n the Coronary Care U n i t of the Vancouver General H o s p i t a l . The p a t i e n t a n x i e t y a t t r i b u t a b l e to the i n t e n s i v e c a r e u n i t was determined to be a v a r i a b l e t h a t c o u l d i n f l u e n c e the p r e f e r e n c e s expressed by t h i s p a t i e n t i n r e l a t i o n to oth e r p a t i e n t s who were i n t e r v i e w e d i n the d o c t o r ' s o f f i c e . The 'angina* groups were determined u s i n g the d i s a b i l i t y s c a l e of the Canadian C a r d i o l o g y I n s t i t u t e f o r he a r t d i s e a s e p a t i e n t s with angina (see Chapter 1 ) . Three assessments of d i s a b i l i t y l e v e l were made. F i r s t , the p a t i e n t s e l e c t e d h i s / h e r d i s a b i l i t y l e v e l by d e s c r i b i n g e x e r c i s e - i n d u c e d p a i n and subsequent d i s a b i l i t y . Second, the r e s e a r c h e r made an e s t i m a t e u s i n g the p a t i e n t h i s t o r y and the d i s a b i l i t y s c a l e . F i n a l l y , the p a t i e n t ' s p h y s i c i a n s t a t e d the d i s a b i l i t y l e v e l . U s u a l l y , a l l t h r e e assessments were the same. When t h e r e was disagreement, the p h y s i c i a n ' s assessment was used. P a t i e n t s w i t h d i s a b i l i t y l e v e l s one and two were e l i g i b l e f o r the 'mild angina' group, w h i l e p a t i e n t s w i t h d i s a b i l i t y l e v e l s t h r e e and f o u r were p l a c e d i n the 'severe angina' group. The group of 15 h e a l t h y a d u l t s and 37 h o s p i t a l a d m i n i s t r a - t o r s a c t e d as c o n t r o l s so t h a t a d e t e r m i n a t i o n c o u l d be made of whether the e f f e c t s of d i a g n o s i s of heart d i s e a s e and the presence of symptoms i n f l u e n c e d d e c i s i o n making beh a v i o u r . In o t h e r words, the o b j e c t was to determine the importance of the nature of the d e c i s i o n i n unde r s t a n d i n g d e c i s i o n making beha- v i o u r . S u b j e c t s were to make c h o i c e s i n a r e a l s i t u a t i o n s i m i l a r to those i n an h y p o t h e t i c a l s i t u a t i o n . The 52 h e a l t h y c o n t r o l s u b j e c t s were asked to imagine t h a t t h e i r d o c t o r had diagnosed the presence of coronary h e a r t d i s e a s e . They were then asked to answer the q u e s t i o n n a i r e imagining t h a t they would e x p e r i e n c e symptoms sometime i n the f u t u r e , and t h a t they would r e q u i r e treatment i n the f u t u r e . The r e s e a r c h e r d e s c r i b e d what angina p a i n might be l i k e and how angina c o u l d l i m i t normal a c t i v i t i e s . The d e s c r i p t i o n of p a i n used was taken from Chapter 1. S u b j e c t s were g i v e n the Canadian C a r d i o l o g y I n s t i t u t e g r a d i n g of l e v e l s of angina as a r e f e r e n c e f o r the d i s a b i l i t y caused by angin a . 4.0. P a i n as a F a c t o r i n D e c i s i o n Making P a t i e n t s were s e l e c t e d f o r t h i s study to r e p r e s e n t the spectrum of p a i n t y p i c a l of p a t i e n t s w i t h coronary a r t e r y d i s e a s e . Some p a t i e n t s e x p e r i e n c e d no p a i n , w h i l e o t h e r s were moderately or s e v e r e l y d i s a b l e d by che s t p a i n due to angin a . In order f o r a meaningful a n a l y s i s of the q u e s t i o n s r e l a t i n g to p r e f e r e n c e s f o r m o r b i d i t y and treatments accompanied by r i s k , i t was important to have an un d e r s t a n d i n g of how d i s a b l e d each p a t i e n t was due to the symptoms of co r o n a r y h e a r t d i s e a s e . Each 57 p a t i e n t was asked to d e s c r i b e the onset and d u r a t i o n of p a i n , the c u r r e n t therapy, and to p r o v i d e l i m i t e d demographic d a t a . Each asymptomatic p a t i e n t d e s c r i b e d h i s / h e r a t t i t u d e s towards any d i s a b i l i t y caused by c o r o n a r y h e a r t d i s e a s e or o t h e r h e a r t d i s e a s e found i n p a t i e n t s i n t h i s group. The e x p e r i e n c e of p a i n i s an a t t r i b u t e of many d i s e a s e s t a t e s . In o r d e r to a v o i d p a i n comparisons which are not meaningful between p a t i e n t s , p a i n comparison was made w i t h i n s u b j e c t s o n l y ( C h r i s t e n s e n - S z a l a n s k i , 1984). P a t i e n t s were asked to v i s u a l i z e p a i n c o n t i n u i n g at i t s c u r r e n t s e v e r i t y , and to v i s u a l i z e one, two and f i v e years without p a i n . Twenty-nine of the p a t i e n t s whose q u e s t i o n n a i r e responses were a n a l y s e d were e x p e r i e n c i n g the p a i n of a n g i n a . The p o s s i - b i l i t y of p a t i e n t s v i o l a t i n g p r e f e r e n c e s expressed d u r i n g a r e s p i t e from p a i n , compared to p r e f e r e n c e s expressed d u r i n g p e r i o d s when they e x p e r i e n c e d p a i n , was expected ( C h r i s t e n s e n - S z a l a n s k i , 1984). True v a l u e s may become suspended as a r e s u l t of the overwhelming need f o r p a i n r e l i e f ( S c h e l l i n g , 1985) . To somewhat compensate f o r t h i s problem, p a t i e n t s were encouraged to choose treatments whose outcomes would be s t r e f l e c t t h e i r needs as they f e l t them to be d u r i n g the q u e s t i o n n a i r e as w e l l as d u r i n g p e r i o d s of p a i n . T h i s s t r a t e g y was adopted because of S c h e l l i n g ' s (1985) f i n d i n g t h a t people d i s c o u n t the p a s t h i g h l y , s i n c e the p a i n they have a l r e a d y s u f f e r e d doesn't hurt them now. The i n t e r e s t i n g a s p e c t of angina p a i n i s t h a t p a t i e n t s know i t 58 w i l l be back, and remember w e l l what i t i s l i k e . T h i s i s g e n e r a l - l y t r u e of most r e c u r r i n g or c h r o n i c p a i n . Understanding beha- v i o u r responses to c h r o n i c angina p a i n appears to be based on d i f f e r e n t c r i t e r i a than the case of l a b o u r p a i n , which although extreme, i s i n t e r m i t t e n t and s e l f l i m i t i n g . Research has a l s o shown t h a t people are not c o n s i s t e n t i n the c h o i c e s they make even without the added c o n f u s i o n of p a i n (Arrow, 1971). P a i n , then, can be c l a s s i f i e d as a d i s e a s e symptom t h a t may a l t e r t r u e p r e f e r e n c e s ( C h r i s t e n s e n - S z a l a n s k i , 1984). However, th e r e i s an a d a p t i v e v a l u e to being more s e n s i t i v e to a s t a t e of patn than a s t a t e of non-pain or p l e a s u r e . The person i n p a i n i s motivated to take some a c t i o n to a l l e v i a t e the p a i n by a l t e r i n g the s i t u a t i o n t h a t caused i t . There remains the dilemma a f f e c t - i n g t h i s study of not knowing whether a p a t i e n t ' s p r e f e r e n c e i s merely a s h o r t - t e r m a d a p t i v e response to p a i n . 5.0. I n t r o d u c i n g S u b j e c t s to the Q u e s t i o n n a i r e At the o u t s e t of each i n t e r v i e w , demographic v a r i a b l e s were c o l l e c t e d i n a manner s i m i l a r to a p a t i e n t h i s t o r y . The q u e s t i o n n a i r e c o n t a i n e d a s h o r t form (see Appendix I) a s k i n g : age, sex, h e a l t h h i s t o r y , m a r i t a l s t a t u s , number of c h i l d r e n , job type, l e n g t h of symptoms, and l i f e s t y l e r i s k f a c t o r s . Some p a t i e n t s spent as much as h a l f an hour d e s c r i b i n g t h e i r h i s t o r y . 59 The reason f o r a s k i n g p a t i e n t s to repeat a h i s t o r y a l r e a d y taken by the p h y s i c i a n was to h e l p the p a t i e n t f e e l c o m f o r t a b l e , to encourage the p a t i e n t to communicate to the r e s e a r c h e r , and to p r o v i d e i n f o r m a t i o n on the k i n d of p a i n and d i s a b i l i t y caused by the p a t i e n t ' s h e a r t d i s e a s e . T h i s h i s t o r y was a l s o important f o r p a t i e n t s w i t h asymptomatic coronary h e a r t d i s e a s e because t h e i r p r e v i o u s h e a l t h care e x p e r i e n c e s p r o v i d e d important data t h a t c o u l d have an i n f l u e n c e i n treatment c h o i c e s . The treatment s e e k i n g behaviour of p a t i e n t s w i t h c a r d i a c a r r y t h m i a s , pace- makers, and v a l v e d i s e a s e was an important f a c t o r i n r e d u c i n g d i s p a r i t i e s between the h e a r t d i s e a s e c o n t r o l group and the h e a r t d i s e a s e group w i t h angina p a i n . The reason f o r t a k i n g a h i s t o r y from a l l p a t i e n t s was to ensure t h a t data were a v a i l a b l e t o i d e n t i f y s i m i l a r i t i e s and d i f f e r e n c e s between p a t i e n t and s u b j e c t groups. I t i s a l s o m e t h o d o l o g i c a l l y important to have ev e r y s u b j e c t r e c e i v e the same q u e s t i o n n a i r e e x p e r i e n c e . P a t i e n t s were not asked to d e s c r i b e t h e i r p r o g n o s i s (the f u t u r e course of the d i s e a s e ) i n order not to cause a n x i e t y . However, s u b j e c t s were asked to s t a t e the number of years they expected to l i v e . T h i s q u e s t i o n d i d cause some a n x i e t y f o r a few p a t i e n t s . 6.0. The S u b j e c t ' s Role S u b j e c t s are a c t i v e p a r t i c i p a n t s i n any experiment. P o t e n t i a l problems t h a t c o u l d develop i n the course of adminis- 60 t e r i n g the q u e s t i o n n a i r e were e x p l o r e d by a s k i n g : how w i l l the s u b j e c t s be m o t i v a t e d , how w i l l they p e r c e i v e t h i s r e s e a r c h , and what cues w i l l the p a t i e n t s p i c k up? In any experiment of t h i s type, some mutual r o l e e x p e c t a - t i o n s become d e f i n e d , i f not at the o u t s e t , c e r t a i n l y d u r i n g the r e s e a r c h . Orne (1962) has shown t h a t s u b j e c t s tend to p l a c e themselves under the c o n t r o l of the experimenter, and o f t e n do not i n q u i r e about the purpose or d u r a t i o n of the experiment. S u b j e c t s have been observed to perform meaningless t a s k s f o r hours i n an e f f o r t to be compliant (Orne, 1962, p. 156). P a r t of t h i s behaviour may be s t i m u l a t e d by the b e l i e f t h a t r e s e a r c h may make a c o n t r i b u t i o n to knowledge and i s t h e r e f o r e important. For t h i s reason, s u b j e c t s i n the p r e s e n t s t u d y were d e b r i e f e d and o f f e r e d a summary r e p o r t of f i n d i n g s . Any p a t i e n t s wanting feedback on t h e i r p r e f e r e n c e s were g i v e n a v e r b a l summary of the e v i d e n t d e c i s i o n making behaviours e x h i b i t e d i n the responses. In terms of demand c h a r a c t e r i s t i c s of the experiment (cues t h a t convey the purpose of the r e s e a r c h ) , the r e s e a r c h e r s t r i v e d to e l i m i n a t e b i a s by e x p l a i n i n g the purpose c l e a r l y at the o u t s e t . When s u b j e c t s understand the purpose of the r e s e a r c h they appear to make every e f f o r t to be honest and h e l p f u l (Orne, 1962) . In a d d i t i o n , the s u b j e c t s i n t h i s study a c t i v e l y worked toward s o l v i n g the q u e s t i o n s , which has been suggested as a normal mechanism f o r making the r e s e a r c h e x p e r i e n c e more meaningful (Weick, 1967). 61 A p o t e n t i a l source of b i a s i n the a t t i t u d e s towards r i s k of p a t i e n t s w i t h p a i n and p a t i e n t s w ithout p a i n , c o u l d have a r i s e n from the treatment s e e k i n g behaviour due to angina p a i n . In a d d i t i o n , some p a t i e n t s w i t h angina had a l r e a d y undergone bypass s u r g e r y which may have a l t e r e d a t t i t u d e s towards s u r g i c a l r i s k . For example, a p a t i e n t who has s u r v i v e d s u r g e r y w i t h a 10% r i s k of death may f e e l t h a t a 10% r i s k i s 'low', w h i l e a p a t i e n t a n t i c i p a t i n g t h i s r i s k may b e l i e v e i t i s 'hi g h * . To t r y to reduce the b i a s t h a t treatment e x p e r i e n c e c o u l d g e n e r a t e , outcomes or treatments were not i d e n t i f i e d by name. T h i s c h o i c e was r e i n f o r c e d by McNeil e t . a l . ' s (1978) f i n d i n g t h a t many s u b j e c t s i n a study of cancer treatment had an a v e r s i o n to the words " r a d i a t i o n t h erapy". 7.0. I n t e r v i e w e r B i a s To e v a l u a t e the a d m i n i s t r a t i o n of the q u e s t i o n n a i r e , two p r o f e s s o r s e x p e r i e n c e d i n d e c i s i o n r e s e a r c h p a r t i c i p a t e d i n a t e s t of the r e s e a r c h e r ' s a b i l i t y to conduct a s t r u c t u r e d i n t e r - view i n a n e u t r a l manner. One s o c i a l worker completed the q u e s t i o n n a i r e i n an i n t e r v i e w s i t u a t i o n i n order to e v a l u a t e the r e s e a r c h e r ' s s k i l l s i n p r e s e n t i n g q u e s t i o n s to p a t i e n t s who may be a n x i o u s . A s e n i o r s t a f f p h y s i c i a n a t the Vancouver General H o s p i t a l p a r t i c i p a t e d i n a s t r u c t u r e d i n t e r v i e w as a ' p a t i e n t ' and a s s e s s e d the r e s e a r c h e r ' s s k i l l s at t a k i n g a p a t i e n t h i s t o r y and answering p a t i e n t ' s q u e s t i o n s . 62 The author of the study conducted a l l the s t r u c t u r e d i n t e r v i e w s ( q u e s t i o n n a i r e s ) . In order to c o n t r o l b i a s i n the a d m i n i s t r a t i o n of the q u e s t i o n n a i r e the f o l l o w i n g s t e p s were employed. F i r s t , the r e s e a r c h e r was i n t r o d u c e d to the p a t i e n t by the p h y s i c i a n who r e c r u i t e d the p a t i e n t . The r e s e a r c h e r always wore a white coat and i d e n t i f i c a t i o n t a g t y p i c a l of h o s p i t a l employees, and used an o f f i c e i d e n t i c a l to those of the p h y s i c i a n s . Second, the r e s e a r c h e r p r o v i d e d the l e t t e r of i n t r o d u c t i o n to each s u b j e c t and p r o v i d e d a memorized v e r b a l i n t r o d u c t i o n d e l i v e r e d i n a f r i e n d l y manner. T h i r d , f o r each item on the q u e s t i o n n a i r e , a s t a n d a r d i z e d answer f o r a n t i c i p a t e d p a t i e n t q u e s t i o n s was pr e p a r e d . The r e s e a r c h e r p r o v i d e d the same e x p l a n a t i o n each time a q u e s t i o n was r a i s e d , and the r e s e a r c h e r d i d not show any s i g n s of a p p r o v a l or d i s a p p r o v a l f o r p a t i e n t responses, except to nod and say, " t h a t ' s f i n e . " P a t i e n t s were reminded t h a t t h e r e were no r i g h t answers. F i n a l l y , c o n s i s t e n t use of the v i s u a l a i d s f o r each q u e s t i o n was made, whether or not the p a t i e n t expressed a need f o r the a i d . 8.0. P a t i e n t Assurance A n x i e t y i s a r e a l phenomenon i n medi c a l care and i n medi c a l r e s e a r c h . T h i s study d e a l t w i t h p a t i e n t a n x i e t y by a s k i n g p a t i e n t s about t h e i r f e e l i n g s b e f o r e and a f t e r they p a r t i c i p a t e d i n the q u e s t i o n n a i r e (Mooney, 1977, p. 132). 63 Less a n x i e t y was n o t i c e d i n the h e a l t h y s u b j e c t s than i n the h e a r t d i s e a s e p a t i e n t s . T h i s was expected, based on Mooney's (1977) f i n d i n g t h a t i n d i v i d u a l s i n a h y p o t h e t i c a l s i t u a t i o n may not be a b l e to take i n t o account the a n x i e t y a s s o c i a t e d with a r e a l r i s k s i t u a t i o n . P a t i e n t a n x i e t y was a l s o a l l e v i a t e d with formal a s s u r a n c e s . A d e t a i l e d p r o t o c o l f o r p a t i e n t assurance (a l e t t e r t e l l i n g p a t i e n t s t h a t the r e s e a r c h w i l l not i n t e r f e r e w i t h t h e i r t r e a t - ment) was developed f o r use by the s u b j e c t s i n t h i s study (Thomp- son, e t . a l . , 1984). The items covered i n the l e t t e r were adapted from Thompson e t . a l . (1984) and l i s t e d below. The p a t i e n t assurance document i s found i n Appendix I. 1. P a t i e n t s are assured of anonymity and c o n f i d e n t i a l i t y . 2. The r e s e a r c h e r e x p l a i n s the r a t i o n a l e and importance of the r e s e a r c h . 3. The q u e s t i o n s are as c l o s e to r e a l s i t u a t i o n s as i s f e a s i b l e . 4. Any p u r e l y h y p o t h e t i c a l s i t u a t i o n s are c l e a r l y i d e n t i f i e d . 5. Props such as d i c e and diagrams are used to e x p l a i n the q u e s t i o n s and how they may be answered. 6. P a t i e n t s are a s s u r e d t h a t t h e r e a r e no ' r i g h t answers'. 7. P a t i e n t s are d e b r i e f e d and asked i f answering the q u e s t i o n s has made them more anxious about t h e i r c o n d i t i o n . The r e s e a r c h p r o j e c t , i n c l u d i n g the complete q u e s t i o n n a i r e , was s u b j e c t to the s c r u t i n y of the E t h i c s Committee of the U n i v e r s i t y of B r i t i s h Columbia. The p r o j e c t was a l s o e v a l u a t e d 64 by the C a r d i o l o g y D i v i s i o n of the Vancouver Gen e r a l H o s p i t a l and the V i c e P r e s i d e n t and D i r e c t o r of Research f o r the h o s p i t a l . ' W r i t t e n p e r m i s s i o n from these t h r e e sources was r e q u i r e d b e f o r e any p a t i e n t s c o u l d p a r t i c i p a t e . F o l l o w i n g h o s p i t a l r e g u l a t i o n s , p a t i e n t s were requested to g i v e w r i t t e n consent to t h e i r p h y s i c i a n b e f o r e the r e s e a r c h e r was gi v e n the p a t i e n t ' s name. The consent form a l s o appears i n Appendix I . 9.0. A t t r i b u t e s of P a t i e n t Choice There are many f a c t o r s r e l e v a n t to a p a t i e n t ' s c h o i c e of treatment f o r coronary h e a r t d i s e a s e . For the purposes of t h i s study, these have been l i m i t e d to p a i n , m o r b i d i t y , l e n g t h of h o s p i t a l s t a y , and h e a l t h outcomes. Choices based on r e a l income and net worth measures have been avoided because they have v e r y l i t t l e i n f l u e n c e on a p a t i e n t ' s access to h e a l t h care i n Can- ada.1 Choice of a treatment t h a t c o u l d a l t e r the course of the d i s e a s e has been excluded because most i n t e r v e n t i o n s i n coro n a r y h e a r t d i s e a s e treatment are not a b l e to s i g n i f i c a n t l y a l t e r the course of p r o g r e s s i v e a t h e r o s c l e r o s i s . K l e i n (1983) has s t a t e d t h a t people t h i n k about o n l y a subset of a l l r e l e v a n t a t t r i b u t e s when the c h o i c e s are broad or ; 1 A u s e f u l d i s t i n c t i o n may be made between the c o s t s of s u r g i c a l treatment f o r coro n a r y h e a r t d i s e a s e which are p a i d by Medicare, and the drug c o s t s of medi c a l therapy f o r co r o n a r y h e a r t d i s e a s e which are p a i d by the p a t i e n t . 65 v a r i e d . For each h e a r t p a t i e n t , o n l y a few a t t r i b u t e s are r e l e v a n t a c r o s s the range of treatment o p t i o n s . Many a t t r i b u t e s w i l l be e v a l u a t e d by the p h y s i c i a n a c t i n g as an agent or a d v i s o r to the p a t i e n t , w h i l e a number of a t t r i b u t e s w i l l be too d i f f i - c u l t f o r some p a t i e n t s to u t i l i z e because of l i m i t s on a b i l i t y to process i n f o r m a t i o n . Some problems may a r i s e due to the c h o i c e of outcome a t t r i b u t e s . Values c l o s e t o g e t h e r may demonstrate e r r o r s of p r o p o r t i o n a l d i f f e r e n c e of g r e a t e r magnitude than v a l u e s near the extreme p o i n t s . For example, p a t i e n t s may r e a d i l y d i s t i n g u i s h between two weeks i n h o s p i t a l w i t h p a i n and two weeks i n good h e a l t h , but they may have d i f f i c u l t y d i s t i n g u i s h i n g between two weeks i n h o s p i t a l r e c o v e r i n g from s u r g e r y and two weeks as an i n v a l i d a t home w i t h s e v e r e angina p a i n . So, even i f t h e r e i s a r e a l v a l u e d i f f e r e n c e f o r the p a t i e n t between these two s t a t e s , measurement of t h i s d i f f e r e n c e may not be p o s s i b l e . To compen- s a t e f o r t h i s d i f f i c u l t y , the q u e s t i o n n a i r e anchors p a t i e n t responses to 'very good' and 'very bad' outcomes, and i t attempts to o f f e r c h o i c e s w i t h i n a range of a t t r i b u t e s of treatment out- comes. The process of f i n d i n g an outcome c o n s i d e r e d by most s u b j e c t s to be a 'good outcome', such as no more angina p a i n ; and an outcome c o n s i d e r e d to be a 'bad outcome' such as death or permanent d i s a b i l i t y i s known as 'anchoring'. 66 10.0. Measuring U t i l i t y i n the Heart Study U t i l i t y r e f l e c t s the d e s i r a b i l i t y of an outcome or the v a l u e of one outcome as compared to another (Keeny and R a i f f a , 1976; Merz, 1983). I t s numerical v a l u e i s a t t a c h e d to the "worth of a consequence" or the outcome of a d e c i s i o n ( L i n d l e y , 1976, p. 101). A u t i l i t y s c a l e i s a d e s c r i p t i o n of how p r e f e r e n c e s change as v a r i o u s f a c t o r s i n the environment change. For example, i f a p a t i e n t w i t h cancer of the lung has the lung removed s u r g i c a l l y and i s otherwise capable of l i v i n g a normal l i f e , the worth of l i v i n g w i t h o n l y one lung has a measurable u t i l i t y . T h i s number i s u s u a l l y expressed as a p r o p o r t i o n of the v a l u e of l i v i n g i n p e r f e c t h e a l t h . For p a t i e n t s with c o r o n a r y h e a r t d i s e a s e , the treatment u t i l i t y i s made up of a number of components, both p o s i t i v e and n e g a t i v e . P o s i t i v e components (or outcomes) i n c l u d e : 'cure' of the h e a r t d i s e a s e , r e l i e f from symptoms such as p a i n , e l i m i n a t i o n or r e d u c t i o n of d o l l a r c o s t s of h o s p i t a l treatment or drug therapy, and e s t a b l i s h i n g a f i r m d i a g n o s i s (Berwick and Wein- s t e i n , 1985). Negative outcomes i n c l u d e : p h y s i c a l or emotional d i s a b i l i t y , f a m i l y d i s r u p t i o n , l e n g t h y h o s p i t a l i z a t i o n , s i d e e f f e c t s from drugs, c o n t i n u e d or more severe p a i n , c o n t i n u i n g c o s t s , and death ( K a s s i r e r , 1976, p. 155). S t a t e d p r e f e r e n c e s f o r a treatment outcome are i n d i c e s not o n l y of the s u b j e c t i v e v a l u e of the treatment to the p a t i e n t but a l s o i t s v a l u e to the p a t i e n t ' s f a m i l y . A number of the study 67 i n t e r v i e w s (10%) i n c l u d e d f a m i l y members who took an a c t i v e i n t e r e s t i n the s u b j e c t ' s p a r t i c i p a t i o n . Von Neumann and Morgenstern (1944) have o f f e r e d an example of the e s t i m a t i o n of an o r d i n a l v a l u e f o r u t i l i t y . B r i e f l y , " i f an i n d i v i d u a l p r e f e r s A to the 50-50 combination of B and C (while p r e f e r i n g C to A and A to B) then h i s p r e f e r e n c e of A over B i s g r e a t e r than the p r e f e r e n c e of C over A" (Von Neumann and Morgenstern, 1944, p. 20). At l e a s t an o r d i n a l placement of A, B and C can r e s u l t from t h i s c h o i c e . The q u e s t i o n n a i r e developed to e l i c i t p a t i e n t p r e f e r e n c e s uses t h i s n o t i o n of measurement of u t i l i t y . T o r r a n c e e t . a l . (1982) have d e s c r i b e d a method they used to develop a c a r d i n a l o r d e r i n g of the u t i l i t y of v a r i o u s h e a l t h s t a t e s . S u b j e c t s were asked to p l a c e arrows c o r r e s p o n d i n g to h e a l t h s t a t e s on a ' f e e l i n g thermometer 1. The s p a c i n g between the arrows was the source of data on the r e l a t i v e d i f f e r e n c e between the v a l u e of v a r i o u s h e a l t h s t a t e s . P e r f e c t h e a l t h was l i s t e d as 100 and death was l i s t e d as z e r o . Torrance e t . a l . (1982) suggested t h a t u t i l i t i e s measure the va l u e of the h e a l t h s t a t e independent of the p r o g n o s i s of the p a t i e n t . In other words, even i f a h e a r t p a t i e n t w i l l always l i v e under the t h r e a t of a m y o c a r d i a l i n f a r c t i o n , l i f e without the t h r e a t w i l l have a measurable u t i l i t y . Using a u t i l i t y measure a l l o w s the combination of many a t t r i b u t e s of h e a l t h i n t o a common denominator, such a ' q u a l i t y of l i f e y e a r s ' . T h i s measure 68 d i s c o u n t s years of s i c k n e s s or d i s a b i l i t y so t h a t more d i s a b l e d years of l i f e a r e then e q u i v a l e n t to one year of good h e a l t h . In order to a v o i d an e x p l a n a t i o n of p r o b a b i l i t i e s , T orrance e t . a l . (1982) used a t r a d e - o f f between l i v i n g i n p e r f e c t h e a l t h f o r 'x' years and l i v i n g w i t h i l l h e a l t h f o r 'x + y' y e a r s . The p o i n t of i n d i f f e r e n c e between these s i n g u l a r c h o i c e s y i e l d e d a u t i l i t y measure. As Lust e d (1968, p. 154) noted, " r e l a t i v e u t i l i t i e s f o r an i n d i v i d u a l a re measurable, but a b s o l u t e u t i l i t i e s are not. The person i s f r e e to a s s i g n a r b i t r a r y u t i l i t y v a l u e s , and a u t i l i t y f u n c t i o n i s determined as f o l l o w s : I f the d e c i s i o n maker i s i n d i f f e r e n t between two a l t e r n a t i v e s , the expected u t i l t i y of the a l t e r n a t i v e s i s the same." Components of the a v a i l a b l e c h o i c e s are not s i n g u l a r , but are a c t u a l l y v e c t o r s of outcomes t h a t may be i d e n t i f i e d by a prominent a t t r i b u t e . A number of components of such a v e c t o r were examined i n t h i s study: a h o s p i t a l s t a y , c o n v a l e s c e n c e at home, p a i n , and r i s k of death. P a t i e n t s were asked to i d e n t i f y the most prominent a t t r i b u t e of the treatment outcome v e c t o r . For example, a p a t i e n t may have i d e n t i f i e d 'being a b l e to work i n the garden' as the most important a t t r i b u t e of convalescence; or 'being a b l e to p l a y g o l f as the most important outcome of p a i n c o n t r o l . 1 1 . 0 . Measurement S t r a t e g i e s In the p a t i e n t p r e f e r e n c e study simple measurement s t r a - 69 t e g i e s were f o l l o w e d , assuming t h a t , as Beach and Barnes (1983) found, p a t i e n t s would t r y to d e s c r i b e t h e i r p r e f e r e n c e s r e g a r d - l e s s of how they were asked to communicate. To h e l p p a t i e n t s understand p r o b a b i l i t i e s of outcomes, the q u e s t i o n n a i r e was supported by bar graphs and diagrams and the r e s e a r c h e r adminis- t e r i n g the q u e s t i o n n a i r e answered s u b j e c t s ' q u e s t i o n s and demonstrated p r o b a b i l i t i e s w i t h d i c e and c o i n s . One q u e s t i o n was i l l u s t r a t e d w i t h f o u r empty p i l l c a p s u l e s , each r e p r e s e n t i n g a 25% chance of treatment r i s k , (see Appendix II) S u b j e c t s were asked to d e s c r i b e t h e i r p r e f e r e n c e s f o r a l t e r n a t i v e outcomes wit h a t t e n d a n t b e n e f i t s and c o s t s (or r i s k s of n e g a t i v e outcomes). They were a l s o asked to s t a t e the v a l u e of a l t e r n a t i v e outcomes. S e v e r a l methods of e l i c i t i n g p a t i e n t p r e f e r e n c e s were chosen f o r ease of a d m i n i s t r a t i o n of the q u e s t i o n n a i r e and because more complex methods have not been shown to be s i g n i f i c a n t l y b e t t e r . These methods i n c l u d e d : the standard gamble, t i m e - t r a d e - o f f t e c h n i q u e s , s c e n a r i o s , r a n k i n g , and o r d e r i n g . 11.1. Standard Gamble and Comparisons The 'standard gamble' method of e l i c i t i n g p e r s o n a l p r e f e r - ences i n a s i t u a t i o n of u n c e r t a i n t y has been a t t r i b u t e d to Von Neumann and Morgenstern (1944) . In t h i s method, s u b j e c t s are asked to s t a t e an e q u i v a l e n t outcome to a 50-50 gamble d e s c r i b e d i n a s c e n a r i o . They may a l s o be asked to choose between a 50-50 70 gamble and an i n t e r m e d i a t e outcome t h a t occurs with c e r t a i n t y . Such an i n t e r m e d i a t e outcome i s c a l l e d a ' c e r t a i n t y e q u i v a l e n t 1 . The b a s i c p r i n c i p l e s of t h i s method were d e s c r i b e d i n more d e t a i l above i n the d i s c u s s i o n of an o r d i n a l s c a l e f o r u t i l i t y . V e r t i n s k y and Wong (1975) e v a l u a t e d two methods of p r e f e r - ence measurement t h a t were u s e f u l f o r the development of the q u e s t i o n n a i r e . The f i r s t method used s c e n a r i o s to p r e s e n t d i f f e r e n t a l t e r n a t i v e s to s u b j e c t s . The a l t e r n a t i v e method d e s c r i b e d the p r o b a b i l i t y of a p o s i t i v e outcome coupled w i t h the p r o b a b i l i t y of a n e g a t i v e outcome (Von Neumann and Morgenstern, 1944). These gambles o f f e r e d equal chances at e i t h e r a s m a l l or l a r g e number of bed r e s t days due to treatment outcomes f o r an i l l n e s s . S u b j e c t s were asked to s t a t e how many days they would r e s t i n bed f o r sure r a t h e r than take a gamble o f f e r i n g e i t h e r a long Or a s h o r t h o s p i t a l s t a y . Each s u b j e c t ' s u t i l i t y was c a l c u l a t e d from s t a t e d u t i l i t i e s of the a l t e r n a t i v e bed r e s t days. The f o l l o w i n g formula was used: u(x) = 0.50 u(a) + 0.50 u(b) The s m a l l number of days of bed r e s t was s e t to zero and the l a r g e number (up to 15) was s e t to one. In t h i s way, each c h o i c e of a c e r t a i n t y e q u i v a l e n t generated a data p o i n t used to c r e a t e a u t i l i t y measure. S u b j e c t s i n the V e r t i n s k y and Wong (1975) study found the st a n d a r d gamble method to be ' e a s i e r to handle'. Consequently, 71 t h i s method was adapted to the p r e s e n t study to measure p a t i e n t ' s u t i l i t y f o r years of l i f e w ith c e r t a i n t y versus r i s k of death due to treatment. The s t a n d a r d gamble te c h n i q u e has been compared to c a t e g o r y s c a l i n g by Llewellyn-Thomas e t . a l . (1984). In t h i s study, s c e n a r i o s were used to d e s c r i b e h e a l t h s t a t e s which were e v a l u a t e d by r a t e r s u s i n g both t e c h n i q u e s above. C o n s i s t e n t l y h i g h e r v a l u e s were a s s i g n e d u s i n g the s t a n d a r d gamble t e c h n i q u e . M c N e i l , Weischselbaum, and Pauker (1978) used a s c e n a r i o method i n a study of p a t i e n t p r e f e r e n c e s f o r treatment f o r carcinoma of the bronchus and lung w i t h demonstrated s u c c e s s . The s c e n a r i o was s e p a r a t e d from the p r o b a b i l i t y of outcomes statement and a diagram was used to a s s i s t p a t i e n t s i n v i s u a l i z i n g the p r o b a b i l i t i e s . Diagrams s i m i l a r to those developed by McNeil e t . a l . (1978) were used i n the p r e s e n t study f o r q u e s t i o n s u s i n g p r o b a b i l i t i e s . McNeil e t . a l . (1978) used a 50/50 gamble s t r a t e g y to develop u t i l i t y s c a l e s f o r p a t i e n t s e x p r e s s i n g an a v e r s i o n to s u r g i c a l r i s k . T h e i r method i n v o l v e d f i v e b a s i c s t e p s . F i r s t , p a t i e n t s were asked to choose how many years they would l i k e to l i v e i n good h e a l t h : 10 or 25 y e a r s . Second, these p a t i e n t s were asked to t h i n k of a 50/50 gamble i n terms of a c o i n t o s s . I f heads appeared they would get the l o n g terra s u r v i v a l , i f t a i l s appeared they got the a l t e r n a t i v e , death. T h i r d , these p a t i e n t s were o f f e r e d a c h o i c e between t a k i n g the gamble or s t a t i n g a f i x e d 72 p e r i o d of l i f e e q u i v a l e n t to t h a t gamble. (The lower t h i s c e r t a i n t y e q u i v a l e n t , or guaranteed s u r v i v a l , the more averse a p a t i e n t was to r i s k . ) F o u r t h , the r e s e a r c h e r s took the c e r t a i n t y e q u i v a l e n t ( f o r example, 5 years) and asked the gamble a g a i n , u s i n g the new e q u i v a l e n t i n p l a c e of death ( w r i t t e n as zero years of s u r v i v a l ) . The q u e s t i o n was then a c h o i c e between a 50/50 gamble of 5 years b e f o r e death and the c h o i c e of 10 or 25 years from s t e p 1 and a c e r t a i n t y e q u i v a l e n t s e l e c t e d by the p a t i e n t . F i n a l l y , s t e p f o u r was repeated u s i n g the 50/50 gamble between the c e r t a i n t y e q u i v a l e n t and immediate death, v e r s u s a c h o i c e of a guaranteed s u r v i v a l . P a t i e n t s who were a v e r s e to the r i s k of s u r g i c a l death, chose l e s s than 3 years of s u r v i v a l r a t h e r than take the 50-50 gamble between death and 10 years of good h e a l t h . One purpose of the pr e s e n t study was to measure the u t i l i t y to h e a r t p a t i e n t s of a v o i d i n g the r i s k of s u r g i c a l death. To accomplish t h i s , changes were made to the McNeil e t . a l . (1978) method by r e p l a c i n g the c e r t a i n t y e q u i v a l e n t w i t h a sequence of p r o b a b i l i t i e s of outcomes. T h i s adjustment was made because p a t i e n t s i n the study p r e t e s t group had d i f f i c u l t y d e a l i n g w i t h the s u b s t i t u t i o n of each newly generated c e r t a i n t y e q u i v a l e n t . In order to reduce the p o t e n t i a l e f f e c t s of an e r r o r i n the f i r s t answer c a u s i n g a compound e r r o r i n a l l the answers, each q u e s t i o n was w r i t t e n as an independent one. P a t i e n t s e x p e r i e n c e d l e s s 73 d i f f i c u l t y and demonstrated a b e t t e r u n d e r s t a n d i n g of the p r i n c i p l e behind these q u e s t i o n s when the p r o b a b i l i t i e s were a l t e r e d r a t h e r than the c e r t a i n t y e q u i v a l e n t . 11.2. Ranking and P r e f e r e n c e S c a l i n g Beach and Barnes (1983) expanded on the work of S t i l l w e l l e t . a l . (1982) to demonstrate s e v e r a l approximate measures t h a t were u s e f u l i n e l i c i t i n g s u b j e c t p r e f e r e n c e s . These i n c l u d e d a s imple r a n k i n g method, a seven p o i n t p r e f e r e n c e s c a l e r a t i n g , and v o t i n g . The study determined t h a t "the simple seven p o i n t r a t i n g s c a l e s y i e l d an o r d e r i n g t h a t c o r r e l a t e s .9 w i t h the o r d e r i n g d e r i v e d from the r a n k i n g method and .89 w i t h the o r d e r i n g d e r i v e d from the p o i n t s method" (Beach and Barnes, 1983, p.423). The authors recommended a g a i n s t the v o t i n g method because i t had the lowest c o r r e l a t i o n w i t h o t h e r methods s t u d i e d . Isen and P a t r i c k (1983) a l s o r e p o r t the s u c c e s s f u l use of s c a l i n g to demonstrate p r e f e r e n c e s i n an h y p o t h e t i c a l r i s k s i t u a t i o n . P l i s k i n e t . a l . (1985) have s t a t e d t h a t a p a t i e n t need not attempt an assessment of c h o i c e s i n order to c r e a t e a two a t t r i b u t e u t i l i t y f u n c t i o n . I n s t e a d , the p a t i e n t may be p r e s e n - ted w i t h p a i r s of c h o i c e s and asked to rank the p a i r s . Ranking was f e a s i b l e i n the P l i s k i n (1985) study because the outcome measure (the number of r a d i o g r a p h s performed per year) was a l s o a d e c i s i o n v a r i a b l e t h a t had i n f l u e n c e over the p r o b a b i l i t y of the second a t t r i b u t e ( p r o b a b i l i t y of a t o o t h l e s i o n ) . 74 11.3. Time-Trade-Off Time t r a d e - o f f has been c o n s i d e r e d to be e m p i r i c a l l y e q u i v a l e n t to the Von Neumann and Morgenstern s t a n d a r d gamble by T o r r a n c e e t . a l . (1982). In the T o r r a n c e study, p a t i e n t s were asked to determine a p o i n t of i n d i f f e r e n c e between a l i f e t i m e (70 years) w i t h a c h r o n i c i l l n e s s and a s h o r t e r but h e a l t h y l i f e . The i n t e r v i e w e r supplemented the q u e s t i o n w i t h v i s u a l a i d s . S i n c e no l o t t e r i e s were used, the r e s e a r c h e r s c o u l d not e v a l u a t e the p a t i e n t a t t i t u d e s toward r i s k , i n s t e a d they developed a measure of the p o p u l a t i o n mean of h e a l t h s t a t e s p r e f e r r e d to death. Torrance e t . a l . (1982) recommended t h a t q u e s t i o n s a s k i n g p a t i e n t s to s c a l e a t t r i b u t e s of h e a l t h s t a t e s o f f e r the s u b j e c t s one v e r y bad and one v e r y good outcome. S t a t i s t i c a l a n a l y s i s of the ordered p r e f e r e n c e s i s s i m p l i f i e d by t h i s s t r a t e g y . An example of the t i m e - t r a d e - o f f s t r a t e g y has been r e p o r t e d by Read e t . a l . (1984), who found t h a t s u b j e c t s i n a study of p h y s i c i a n responses to c h o i c e s of h e a l t h outcomes s t a t e d t h a t 15 years of l i f e w i t h severe angina was worth l e s s than 10 years of l i f e w ith moderate angi n a . 12.0. A d m i n i s t e r i n g the Q u e s t i o n n a i r e A d m i n i s t r a t i o n of the q u e s t i o n n a i r e s to i n d i v i d u a l s was chosen over groups so t h a t p a r t i c i p a n t s would f e e l more comfor- t a b l e a s k i n g f o r c l a r i f i c a t i o n and o f f e r i n g a d d i t i o n a l comments. 75 As s t a t e d e a r l i e r , the q u e s t i o n n a i r e was a d m i n i s t e r e d i n a d o c t o r ' s o f f i c e a d j a c e n t to a l a r g e w a i t i n g room i n the C a r d i o - logy Department of the Vancouver Gene r a l H o s p i t a l , and i n an o f f i c e of a c a r d i o l o g y group p r a c t i c e . The q u e s t i o n n a i r e was a d m i n i s t e r e d e s s e n t i a l l y as a s t r u c - t u r e d i n t e r v i e w . S t r u c t u r e d i n t e r v i e w s about h e a l t h s t a t e s have demonstrated s u b j e c t c o n f u s i o n r a t e s of 17% (Kaplan e t . a l . , 1979) w h i l e 27% of i n t e r v i e w s about h e a l t h s t a t e s where p a r t i c i p a t i o n by the r e s e a r c h e r was p r o h i b i t e d were unusable due to i n d i c a t i o n s of s u b j e c t c o n f u s i o n (Torrance e t . a l . , 1982). S e v e r a l p a t i e n t s i n the p r e s e n t study d i d not have adequate r e a d i n g s k i l l s to do the q u e s t i o n n a i r e without h e l p from the r e s e a r c h e r , making the s t r u c t u r e d i n t e r v i e w e s s e n t i a l . T o r r a n c e e t . a l . (1982) found 78% of completed i n t e r v i e w s i n a study of p r e f e r e n c e s f o r h e a l t h s t a t e s had some us a b l e data (they demonstrated no s u b j e c t c o n f u s i o n ) when the i n t e r v i e w e r d i d not attempt to c l a r i f y problems. To i n c r e a s e the number of u s a b l e q u e s t i o n n a i r e s i n the p r e s e n t study, p a t i e n t s w i t h d i f f i c u l t i e s i n u n d e r s t a n d i n g concepts were a s s i s t e d by the r e s e a r c h e r and the prepared v i s u a l a i d s . Usable data was c o l l e c t e d from over 95% of respondents. Three p a t i e n t s (4.4%) were unable, or u n w i l l i n g , to complete s e v e r a l q u e s t i o n s . These q u e s t i o n n a i r e s were excluded from the a n a l y s i s . T o r r a n c e e t . a l . (1982) found t h a t p a t i e n t p r e f e r e n c e q u e s t i o n s were w e l l accepted by the g e n e r a l p u b l i c . A random 76 sample of s u b j e c t s generated a 75% response r a t e i n a l a t e r study by S a c k e t t and Torrance (1984) . Although, p a t i e n t p r e f e r e n c e s based on age of the p a t i e n t have not been e x p l o r e d i n d e t a i l , some eviden c e has been r e p o r t e d on macro-choice d i f f e r e n c e s t h a t appear i n o l d e r p a t i e n t s . C a s s i l e t h e t . a l . (1980) found d i f f e r e n c e s i n c h o i c e behaviour and i n f o r m a t i o n s e e k i n g between younger and o l d e r p a t i e n t s . Younger p a t i e n t s wanted to p a r t i c i p a t e i n d e c i s i o n s , w h i l e many o l d e r p a t i e n t s wanted to a b d i c a t e and l e t d o c t o r s make d e c i s i o n s . C u r l e y e t . a l . (1984) s t u d i e d 306 o u t p a t i e n t s and spouses and found t h a t 33% of o l d e r p a t i e n t s wanted to d e f e r d e c i s i o n s to d o c t o r s . The study a l s o e x p l o r e d the e f f e c t of ambiguity and found t h a t 21% of the s u b j e c t s r e f u s e d ambiguous treatment w h i l e o n l y 3% r e f u s e d r i s k y treatment. Pendelton and House (1984) a l s o c o n f i r m t h a t o l d e r p a t i e n t s w i t h d i a b e t e s are l e s s i n t e r e s t e d i n bei n g i n v o l v e d i n p e r s o n a l c a r e than younger p a t i e n t s . U n f o r t u n a t e l y , i n the p r e s e n t study, even though the q u e s t i o n n a i r e was a d m i n i s t e r e d w h i l e the p a t i e n t ' s were v i s i t i n g t h e i r p h y s i c i a n , ( i n c r e a s i n g the convenience f o r the p a t i e n t ) , the w i l l i n g n e s s to p a r t i c i p a t e was very low. Some of t h i s very low r a t e of response may have been due to the o l d e r ages of many of the p a t i e n t s . 13.0. The Use of P a t i e n t P r e f e r e n c e s Over Time I d e n t i f y i n g p a t i e n t p r e f e r e n c e s and d e v e l o p i n g a u t i l i t y 77 s c a l e f o r p a t i e n t avoidance of treatment r i s k s was a time consuming e f f o r t . I n d i c a t i o n s a r e , however, t h a t once these p r e f e r e n c e s are i d e n t i f i e d they demonstrate s t a b i l i t y over time. T o r r a n c e e t . a l . (1982) found t h a t i n repeated measures of h e a l t h s t a t e p r e f e r e n c e s on the same i n d i v i d u a l , c h o i c e s remained c o n s i s t e n t . T h i s was demonstrated by high c o r r e l a t i o n c o e f - f i c i e n t s (0.86 to 0.94). 14.0. S t a t i s t i c a l A n a l y s i s S e v e r a l d e s i g n and environmental c o n s t r a i n t s l i m i t e d the use of f o r m a l s t a t i s t i c a l a n a l y s i s i n t h i s s t udy. F i r s t , the s m a l l sample s i z e prevented d i v i s i o n of s u b j e c t s by f a c t o r s i n t o groups w i t h enough s u b j e c t s per c e l l f o r meaningful m u l t i v a r i a t e or s t r a t i f i e d a n a l y s i s . A n a l y s i s of r e s u l t s was conducted u s i n g a number of t e s t s f o r s t a t i s t i c a l s i g n i f i c a n c e . Chi square t e s t s were used to i d e n t i f y s i g n i f i c a n t d i f f e r e n c e s between observed and expected f r e q u e n c i e s , and the Mantei c h i square was used to t e s t f o r s i g n i f i c a n t trends (Mantel, 1963). I n t r a - o b s e r v e r v a r i a b i l i t y was asse s s e d u s i n g the Kappa s t a t i s t i c ( S p i t z e r , 1967T. Kappa measures how w e l l two o b s e r v e r s agree or how w e l l a s i n g l e o bserver makes two o b s e r v a t i o n s . T h i s s t a t i s t i c takes i n t o account u n d e r l y i n g chance agreement t h a t c o u l d o c c u r . A s e n s i t i v i t y a n a l y s i s was performed on s e v e r a l q u e s t i o n n a i r e responses by s o r t i n g p a t i e n t c h o i c e s by a p a t i e n t ' s p a s t e x p e r i - 78 ence of a m y o c a r d i a l i n f a r c t i o n and by exposure to c o r o n a r y a r t e r y bypass g r a f t i n g . The r a t i o n a l e f o r t h i s a n a l y s i s was based on the p o s s i b l e i n f l u e n c e these major h e a l t h events c o u l d have on p a t i e n t a t t i t u d e s towards treatment r i s k . The d i f f e r e n c e i n r i s k avoidance between d i a g n o s t i c . g r o u p s was measured u s i n g the t r a p e z o i d r u l e . The i n f l u e n c e of l i f e expectancy on r i s k a v e r s i o n was i l l u s t r a t e d by a f i g u r e r a t h e r than a s t a t i s t i c . 15.0. C o n c l u s i o n s The p r e s e n t study to determine p a t i e n t p r e f e r e n c e s f o r treatment outcomes employed the methods d e s c r i b e d i n t h i s c h a p t e r . E f f o r t s were made to ensure s u b j e c t c o n f i d e n t i a l i t y , reduce s u b j e c t and i n t e r v i e w e r b i a s , and m a i n t a i n c o n s i s t e n c y throughout the data c o l l e c t i o n . Methods s e l e c t e d were those t h a t d i r e c t l y i n v o l v e d p a t i e n t s i n making c h o i c e s . T h i s s t r a t e g y was based on the normative argument t h a t p a t i e n t s ought to p a r t i c i p a t e i n h e a l t h care d e c i s i o n s t h a t a f f e c t the l e n g t h and q u a l i t y of t h e i r l i v e s . The study i n v o l v e d p a t i e n t s i n s t a b l e c o n d i t i o n o n l y . The f o l l o w i n g two c h a p t e r s d e s c r i b e the study q u e s t i o n s , the s u b j e c t s ' responses, a n a l y s i s of the responses, and c l i n i c a l c o n c l u s i o n s drawn from the a n a l y s i s . Chapter t h r e e e x p l o r e s p o t e n t i a l e r r o r s of judgement t h a t c o u l d prevent a p a t i e n t from e x p r e s s i n g a t r u e p r e f e r e n c e . Chapter f o u r e v a l u a t e s the impact 79 of independent v a r i a b l e s on treatment c h o i c e s and p a t i e n t s ' responses to r i s k . 80 CHAPTER 3 THE STUDY OF PATIENT PREFERENCES: E r r o r s of Judgement 1.0. I n t r o d u c t i o n Two o b j e c t i v e s of t h i s s t u d y guided the development of the q u e s t i o n n a i r e used to e l i c i t p a t i e n t p r e f e r e n c e s . The f i r s t was to study p a t i e n t p r e f e r e n c e s under the c o n s t r a i n t s imposed by p a i n and the need to make a c t u a l c h o i c e s f o r therapy f o r coronary h e a r t d i s e a s e . Second, the s t u d y sought to determine i f s e v e r a l p r e v i o u s l y observed e r r o r s of judgement i n d e c i s i o n making i n other c o n t e x t s were demonstrated i n m e d i c a l d e c i s i o n s i n which outcomes ( i n c l u d i n g the r i s k of death) were r e a l . S l o v i c and L i c h t e n s t e i n (1983, p. 598) have r e c o g n i z e d "the importance of m o t i v a t i o n and the need to t e s t nonstudent s u b j e c t s . " A r e l a t i v e l y new s c h o o l of r e s e a r c h on d e c i s i o n - m a k i n g has focused on the i n f l u e n c e of e r r o r s of judgement i n d e c i s i o n making under u n c e r t a i n t y ( S l o v i c and L i c h t e n s t e i n , 1983; Kahrieman and Tversky, 1979; Knetsch and Sinden, 1984; T h a l e r , 1980; McNeil e t . a l . , 1978). An e r r o r of judgement t h a t a r i s e s from a v i o l a t i o n of the axioms of expected u t i l i t y t h e o r y has a l s o been termed a " d e c i s i o n b i a s " by Kahneman and Tversky (1979). One normative c o n s t r u c t of expected u t i l i t y t heory i s t h a t d e c i s i o n makers f o l l o w a " p r e f e r e n c e o r d e r " which i m p l i e s t r a n s i t i v i t y , dominance, and i n v a r i a n c e . T r a n s i s t i v i t y d e s c r i b e s a s i t u a t i o n where i f a l t e r n a t i v e A i s p r e f e r r e d to B, and B to C, then A w i l l be p r e f e r r e d to C. Dominance d e s c r i b e s the c l e a r 81 p r e f e r e n c e of one a l t e r n a t i v e s t a t e over one or more other a l t e r n a t i v e s or s t a t e s . I n v a r i a n c e i s the c o n d i t i o n where s m a l l v a r i a t i o n s i n an outcome w i l l not a f f e c t c h o i c e (Keeny and R a i f f a , 1976) . I n v a r i a n c e does not r e f e r to the way a d e c i s i o n problem i s p r e s e n t e d , such as v a r i a t i o n s i n wording. In t h i s chapter each p o t e n t i a l e r r o r of judgement i s d i s c u s - sed and the q u e s t i o n s used to t e s t i t are d e s c r i b e d . The e r r o r s d e s c r i b e d and t e s t e d i n t h i s study were: the c e r t a i n t y e f f e c t , p r e f e r e n c e r e v e r s a l , the f o r m u l a t i o n e f f e c t of f r a m i n g , c o n s i s - tency of c h o i c e (the s u b s t i t u t i o n e f f e c t ) , asymmetric c h o i c e , w i l l i n g n e s s to pay, and the endowment e f f e c t . The s t u d i e s r e p o r t e d are those whose methods and q u e s t i o n s to s u b j e c t s were most i n f l u e n t i a l i n the development of the p a t i e n t q u e s t i o n n a i r e i n the study of p a t i e n t s w i t h h e a r t d i s e a s e . 2.0. The C e r t a i n t y E f f e c t : an Example of R i s k A v e r s i o n The t h e o r y of expected u t i l i t y s t a t e s t h a t the v a l u e to an i n d i v i d u a l of an outcome i s weighted by the p r o b a b i l i t y of the o c c u r r e n c e of the outcome. T h i s t h e o r y does not a l l o w an event w i t h a h i g h p r o b a b i l i t y outcome or a "sure t h i n g " to have more r e l a t i v e v a l u e than outcomes wi t h any o t h e r l e v e l of p r o b a b i l i t y when these are weighted. Expected u t i l i t y t h e o r y i s v i o l a t e d when d e c i s i o n makers p l a c e p r o p o r t i o n a l l y g r e a t e r v a l u e on a s p e c i f i c outcome that i s c o n s i d e r e d " c e r t a i n " or " f o r s u r e " than they do on an outcome t h a t may occur with r e a s o n a b l e 82 p r o b a b i l i t y . For example, when asked to choose between a 100% chance of winning $300.00 and an 80% chance of $400.00, most s u b j e c t s choose the $300.00 f o r s u r e , even though the expected v a l u e 1 (EV) of the a l t e r n a t i v e c h o i c e i s h i g h e r ($320.00). Kahneman and Tversky (1979) c a l l t h i s phenomenon the o v e r w e i g h t i n g of c e r t a i n t y , or "the c e r t a i n t y e f f e c t " . A number of s t u d i e s i n c o g n i t i v e psychology and i n c l i n i c a l medicine have r e p o r t e d t h a t s u b j e c t s p r e f e r a modest outcome f o r s u r e r a t h e r than a t a k i n g gamble on a v e r y good and a very bad outcome even when the expected v a l u e i s the same (Kahnemen and Tve r s k y , 1979; McNeil e t . a l . , 1978; Pauker, 1976; Keeny and R a i f f a , 1976). Keeny and R a i f f a (1976, p. 149) d e f i n e such a d e c i s i o n maker as "a r i s k a v e r s e p e r s o n " . Kahneman and Tversky (1979) t e s t e d f o r the c e r t a i n t y e f f e c t u s i n g 95 student s u b j e c t s . When they were asked to make a c h o i c e , 20% of the s u b j e c t s chose an 80% chance of $4,000 (EV= $3,200) w h i l e 80% chose $3,000 (EV=$3,000) f o r s u r e . The expected v a l u e of the f i r s t c h o i c e was h i g h e r , but t h i s was overshadowed by the i n f l u e n c e of the c e r t a i n t y of g e t t i n g $3,000. The domination of an outcome with a h i g h p r o b a b i l i t y over an outcome wi t h a lower p r o b a b i l i t y a s s o c i a t e d with a h i g h e r expected v a l u e has a l s o been found by McNeil e t . a l . (1978) i n cancer p a t i e n t s . These p a t i e n t s demonstrated a p r e f e r e n c e f o r 1 The expected v a l u e of an outcome i s c a l c u l a t e d by m u l t i p l y i n g the p r o b a b i l i t i e s and the v a l u e s of each component of the outcome. An expected v a l u e i s i d e n t i f i e d i n the t e x t by the n o t a t i o n ' E V . 83 treatment outcomes ( r a d i a t i o n ) with no r i s k of e a r l y death even though the expected s u r v i v a l time f o r these p a t i e n t s was l e s s than f o r the treatment o p t i o n t h a t had a r i s k of e a r l y death ( s u r g e r y ) . Pauker, Pauker, and McNeil (1981) s t u d i e d p a r e n t s ' c h o i c e s under c o n d i t i o n s t h a t c a r r i e d the r i s k of a n e g a t i v e outcome. T h i s study i n c l u d e d 338 p r o s p e c t i v e p a r e n t s t a k i n g g e n e t i c c o u n s e l l i n g f o r p o s s i b l e d e f e c t s i n unborn c h i l d r e n . These s u b j e c t s were asked: "At what chance of a pregnancy's p r o d u c i n g a s e v e r e l y deformed c h i l d would you p r e f e r an e l e c t i v e a b o r t i o n to the r i s k of having a l i v e - b o r n c h i l d a f f e c t e d by t h a t d e f o r m i t y ? " Parents were a b l e to s t a t e the l e v e l of r i s k of b e a r i n g a deformed c h i l d t h a t would encourage them to e l e c t to have an a b o r t i o n . The d i s t r i b u t i o n of a c c e p t a b l e l e v e l s of r i s k was wide with numerous peaks, i n d i c a t i n g t h a t these p r e f e r e n c e s were i n f l u e n c e d by p e r s o n a l v a l u e s as w e l l as by r i s k . A t t i t u d e s toward treatment r i s k were e x p l o r e d i n the p r e s e n t h e a r t study by a s k i n g p a t i e n t s to determine a t h r e s h h o l d l e v e l of years of p a i n - f r e e l i f e t h a t compensated f o r b e a r i n g a r i s k of death from treatment. In the r i s k avoidance q u e s t i o n p a t i e n t s were expected to demonstrate a p r e f e r e n c e f o r a modest outcome f o r c e r t a i n . A modest outcome r e f e r s to a h e a l t h s t a t e t h a t i s i n t e r m e d i a t e between p e r f e c t h e a l t h and complete d i s a b i l i t y . I f s u b j e c t s p r e f e r r e d the i n t e r m e d i a t e outcome, they were asked to determine 84 the compensation needed to make the a l t e r n a t i v e treatment (with the r i s k ) as good as the modest outcome (with the c e r t a i n t y e f f e c t ) . P a t i e n t s who d i d not s e l e c t the modest outcome were asked to s t a t e the number of a d d i t i o n a l p a i n - f r e e months needed to make the r e j e c t e d o p t i o n e q u i v a l e n t to the p r e f e r r e d o p t i o n . The q u e s t i o n used was d e s c r i b e d as a treatment c h o i c e . L i s t e d below are two treatments w i t h d i f f e r e n t long term out- comes. These treatments have d i f f e r e n t r i s k s . Choose one. Assume t h a t i f you s u r v i v e the treatment you l i v e as l ong as you expect to l i v e , but you w i l l have angina p a i n . treatment A: T h i s treatment c o m p l e t e l y e l i m i n a t e d angina p a i n f o r an average of 6 years f o r 90% of p a t i e n t s , 10% s u f f e r e d c o m p l i c a - t i o n s and d i e d . treatment B: T h i s treatment c o m p l e t e l y e l i m i n a t e d angina p a i n f o r an average of 5 years f o r a l l p a t i e n t s . The r a t i o n a l e f o r a s e n s i t i v i t y a n a l y s i s of t h i s q u e s t i o n was based on the d e t e r m i n a t i o n of how much compensation seemed ' f a i r ' to p a t i e n t s when they were exposed to a r i s k of death of 10%. P a t i e n t s who asked f o r compensation may not have r e a l i z e d t h a t treatment A had an expected p a i n - f r e e time of 5.4 years w h i l e treatment B had 5 years of p a i n - f r e e time. T h i s s e n s i t i v i t y a n a l y s i s allowed an e s t i m a t e of the n e g a t i v e v a l u e of treatment r i s k and the p o s i t i v e v a l u e of a treatment whose outcome was known ' f o r s u r e ' . 85 2.1. R e s u l t s of Questions on the C e r t a i n t y E f f e c t In the c e r t a i n t y e f f e c t q u e s t i o n s , 46 out of 64 s u b j e c t s (72%) s e l e c t e d f i v e years with no angina p a i n ' f o r s u r e ' . These s u b j e c t s were then asked to s t a t e the compensation needed to accept the r i s k y treatment. They asked f o r an average of 4 more years w i t h a range of one to twenty years a d d i t i o n a l good h e a l t h to a c c e p t the 10% r i s k . The expected v a l u e of the r i s k y c h o i c e was 5.4 y e a r s , h i g h e r than the c e r t a i n c h o i c e . The c l i n i c a l i m p l i c a t i o n s of the s t r o n g i n f l u e n c e of the c e r t a i n t y e f f e c t s hould suggest to p h y s i c i a n s t h a t many p a t i e n t s do not v a l u e the l e n g t h of t h e i r l i f e above a number of o t h e r v a l u e s , one of these being the c e r t a i n t y of b eing a l i v e . P a t i e n t s s h o u l d , t h e r e f o r e , be o f f e r e d an o p p o r t u n i t y to express a p r e f e r e n c e f o r a treatment t h a t may, i n the view of the p h y s i c i a n , be l e s s e f f e c t i v e i n p r o l o n g i n g l i f e - i f the o b j e c t i v e of treatment i s to maximize the w e l f a r e , or w e l l - b e i n g of the p a t i e n t . 3.0. P r e f e r e n c e R e v e r s a l S l o v i c and L i c h t e n s t e i n (1983, p. 596) s t a t e d t h a t " P r e f e r e n c e r e v e r s a l s occur when i n d i v i d u a l s are presented with two gambles, one f e a t u r i n g a h i g h p r o b a b i l i t y of winning a modest sum of money (the P b e t ) , the o t h e r f e a t u r i n g a low p r o b a b i l i t y of winning a l a r g e amount of money (the $ b e t ) . " The t y p i c a l 86 f i n d i n g was t h a t people o f t e n chose the P bet but a s s i g n e d a l a r g e r monetary v a l u e to the $ bet even though the expected v a l u e s are the same. T h i s b e h a v i o r i s of i n t e r e s t because i t v i o l a t e s the axiom of p r e f e r e n c e o r d e r . A " p r e f e r e n c e model" i s v i o l a t e d "due to the s t r o n g dependence of c h o i c e and p r e f e r e n c e s upon i n f o r m a t i o n p r o c e s s i n g c o n s i d e r a t i o n s " ( S l o v i c and L i c h t e n s t e i n , 1983, p. 597). L i c h t e n s t e i n and S l o v i c (1971) argued t h a t the way the s u b j e c t s p rocessed i n f o r m a t i o n d i f f e r e d depending on whether the d e c i s i o n was s i m p l y a c h o i c e or whether the s u b j e c t was r e q u i r e d to s e t a p r i c e (or value) on a gamble. In a l a t e r paper, S l o v i c and L i c h t e n s t e i n (1983, p. 598) observed t h a t " c h o i c e s among p a i r s of gambles appeared to be i n f l u e n c e d p r i m a r i l y by proba- b i l i t i e s of winning and l o s i n g " , whereas an a t t r a c t i v e outcome f o r a gamble appeared to encourage a h i g h e r b i d . P r e f e r e n c e r e v e r s a l may a l s o be r e l a t e d to a behaviour p a t t e r n d e s c r i b e d by T h a l e r (1985) i n a study of b e t t i n g beha- v i o u r among race t r a c k p a t r o n s . T h a l e r showed t h a t patrons f r e q u e n t l y p l a c e d a s m a l l bet on a long shot chance to win a l a r g e sum, w h i l e they appeared aver s e to even-money bets indepen- dent of t h e i r p a s t wins or l o s s e s . Kahneman and Tversky (1982) have demonstrated t h a t p r e f e r e n c e r e v e r s a l can be induced by the manner i n which the i n f o r m a t i o n i s p r e s e n t e d to s u b j e c t s . 87 The S l o v i c and L i c h t e n s t e i n (1971) study asked s u b j e c t s to choose between and to b i d f o r the f o l l o w i n g p a i r s of gambles: P a i r #1: 9/12 to win $1.20 and 3/12 to l o s e $.10; (P bet) P a i r #2: 3/12 to win $9.20 and 9/12 to l o s e $2.00. ($ bet) EV f o r P a i r #1 = 0.875; EV f o r P a i r #2 = 0.70. L i c h t e n s t e i n and S l o v i c (1971) found t h a t 63% of s u b j e c t s p r e f e r r e d the 'P bet* to the ' d o l l a r b e t ' w h i l e o n l y 29% of the s u b j e c t s s e t a h i g h e r v a l u e on the-'P b e t ' . G r e t h e r and P l o t t (1979) found t h a t f o r s u b j e c t s who were m o t i v a t e d by r e a l money, 70% of the i n i t i a l c h o i c e s of P bets were r e v e r s e d by the p r i c e s g i v e n to the $ b e t s . The f o l l o w i n g i s one of the p a i r s of gambles i n the G r e t h e r and P l o t t (1979) study. S u b j e c t s were asked to b i d wi t h r e a l money f o r , and to choose between, the f o l l o w i n g p a i r s of gambles: P a i r #1: 35/36 to win $4.00 and 1/36 to l o s e $1.00; (P bet) P a i r #2: 11/36 to win $16.00 and 25/36 to l o s e $1.50. ($ bet) EV f o r P a i r #1 = $3.97; EV f o r P a i r #2 = $3.85. Throughout the q u e s t i o n n a i r e used i n the p r e s e n t study, the 'P bet' i s l a b e l l e d a "sure b e t " and r e f e r s to a h i g h p r o b a b i l i t y of a s h o r t term h e a l t h improvement w h i l e the '$ bet* i s l a b e l l e d a "g a i n b e t " and r e f e r s to a low p r o b a b i l i t y of a long-term h e a l t h improvement. The change i n t e r m i n o l o g y was deemed necessary because t h e r e were no money bets i n the q u e s t i o n s developed f o r the h e a r t study. The q u e s t i o n s used to i d e n t i f y p r e f e r e n c e r e v e r s a l behaviour i n the p r e s e n t study were adapted from r e s e a r c h by S l o v i c and 88 L i c h t e n s t e i n (1971) and from a r e p l i c a t i o n of t h i s work by Gre t h e r and P l o t t (1979). Instead of a money bet, p a t i e n t s i n the p r e f e r e n c e study were asked to 'bet' weeks of h o s p i t a l treatment i n order to 'win' years of r e l i e f of angina p a i n . The g r a p h i c demonstrations used to a s s i s t p a t i e n t s i n u n d e r s t a n d i n g the chances of winning and l o s i n g were adapted from Grether and P l o t t and a d j u s t e d to r e p r e s e n t r e a l p r o b a b i l i t i e s of treatment outcomes, (see Appendix II f o r the v i s u a l a i d s f o r the study.) In the p a t i e n t p r e f e r e n c e q u e s t i o n s , p a t i e n t s were f i r s t asked to s t a t e the number of weeks they would be prepared to s t a y i n h o s p i t a l to a c h i e v e the f o l l o w i n g outcomes s t a t e d as gambles: Outcome A: 98% chance of 2 years with no angina p a i n , 2% chance of p a i n the same as i t i s now. (EV = 2 years w i t h no pain) Outcome B: 25% chance of 8 years w i t h no angina p a i n , 75% chance of p a i n the same as i t i s now. (EV = 2 years w i t h no pain) L a t e r i n the q u e s t i o n n a i r e , p a t i e n t s were asked to s t a t e which was the p r e f e r r e d treatment outcome (A or B) from the same p a i r of gambles. An i n d i f f e r e n c e o p t i o n was i n c l u d e d i n these q u e s t i o n s i n order to reduce b i a s due to what Gr e t h e r and P l o t t (1983, p. 626) c a l l " s y s t e m a t i c r e s o l u t i o n of i n d i f f e r e n c e on the p a r t of 89 s u b j e c t s f o r c e d to r e c o r d a p r e f e r e n c e . " S y s t e m a t i c r e s o l u t i o n o ccurs when s u b j e c t s who may r e a l l y be i n d i f f e r e n t choose the same o p t i o n (e.g. they always choose 'A') every time they f e e l i n d i f f e r e n t . To i d e n t i f y how much p a t i e n t s v a l u e d the d i f f e r e n c e between 100% and 98% chance of treatment s u c c e s s , the q u e s t i o n n a i r e asked p a t i e n t s who chose Treatment A to c o n s i d e r c h o o s i n g a 100% chance of one year w i t h no angina p a i n i n s t e a d of Treatment A. There was c o n s i d e r a b l e r e s i s t a n c e among p a t i e n t s and h e a l t h y s u b j e c t s to changing a c h o i c e . When the s u b j e c t d i d not agree to change, he/she was o f f e r e d the o r i g i n a l year p l u s a d d i t i o n a l months up to 11 more months. The r e s u l t s showed t h a t p a t i e n t s and h e a l t h y s u b j e c t s o v e r v a l u e d the 100% chance of one year f r e e of angina p a i n compared to a 98% chance of two years w i t h no angina p a i n . T h i s was demonstrated by p a t i e n t s and s u b j e c t s a c c e p t i n g much l e s s than the expected v a l u e of a 98% chance of 2 years f r e e from p a i n . Many respondents appeared s a t i s f i e d with a 100% chance of 15 or 18 months. P a t i e n t s who s e l e c t e d the 25% chance of e i g h t years with no angina were asked to c o n s i d e r a 50% chance of f i v e years with no ang i n a . The s e n s i t i v i t y a n a l y s i s of t h i s q u e s t i o n was conducted by a l l o w i n g the p r o b a b i l i t y of the "50% chance of 5 y e a r s " to var y at the s u b j e c t ' s d i s c r e t i o n . The expected v a l u e of a "25% chance of 8 y e a r s " i s two years w h i l e the expected v a l u e of "50% of 5 y e a r s " i s 2.5 y e a r s . Those who chose the 50% chance of f i v e 90 years may have anchored on the 50%, or they may have had an und e r s t a n d i n g of expected v a l u e . Those who co n t i n u e d to choose the "25% chance of 8 y e a r s " were assumed to focus on the outcome (years) r a t h e r than the p r o b a b i l i t y . T h i s s e n s i t i v i t y a n a l y s i s was the s t r a t e g y f o r demonstrating the h y p o t h e s i s of S l o v i c and L i c h t e n s t e i n (1983) s t a t e d above. 3.1. R e s u l t s of P r e f e r e n c e R e v e r s a l Questions The c o n t r i b u t i o n t h i s s t u d y makes to the und e r s t a n d i n g of p r e f e r e n c e r e v e r s a l i s not j u s t a demonstration of i t s presence, but an e x p l o r a t i o n of the i n f l u e n c e of i n d i f f e r e n c e on i t s appearance. In t h i s study, s u b j e c t s were p e r m i t t e d to b i d the same number of weeks i n the h o s p i t a l f o r both t r e a t m e n t s . They were a l s o a b l e to b i d 'no weeks*. When asked to choose between outcomes, s u b j e c t s c o u l d s t a t e i n d i f f e r e n c e , a l t h o u g h o n l y one s u b j e c t a c t u a l l y d i d . C o n s t r a i n t s of the o r i g n i a l d emonstration of p r e f e r e n c e r e v e r s a l were r e l a x e d by a s k i n g f o r 'bets' on a non-money gamble, and by a l l o w i n g i n d i f f e r e n c e . T a b l e 3.1 summarizes the r e s u l t s f o r a l l s u b j e c t s . The c h o i c e s a re l a b e l l e d 'A' and 'B', as they are i n the q u e s t i o n s . I n d i f f e r e n c e i s i d e n t i f i e d as *A=B'. P r e f e r e n c e r e v e r s a l appears i n the lower l e f t c e l l i n the t a b l e , w h i l e the o p p o s i t e of p r e f e r e n c e r e v e r s a l ( c a l l e d an i n c o n s i s t e n t choice) appears i n the upper r i g h t c e l l . Throughout a l l d i a g n o s t i c groups, the hig h 91 p r o b a b i l i t y outcome i s p r e f e r r e d , as shown i n the l e f t hand c e l l s of the t a b l e . T a b l e 3.1 P r e f e r e n c e R e v e r s a l f o r a l l S u b j e c t s , n-64 c h o i c e A>B A=B A<B A>B 22 (34 .4%) 1(1 .6%) 4(6.3%) A=B 9(14 .1%) 0(0 .0%) 5(7.8%) A<B 11(17 .2%) 0(0 .0%) 12(18.8%) note: A r e p r e s e n t s the sure bet B r e p r e s e n t s the g a i n bet 3.2. D i s c u s s i o n When the r e s u l t s from a l l s u b j e c t s were t a b u l a t e d , o n l y 11 out of 64 (17%) e x h i b i t e d p r e f e r e n c e r e v e r s a l . T h i s f i n d i n g i s c o u n t e r b a l a n c e d by f o u r s u b j e c t s (6%) who e x h i b i t e d a d e c i s i o n p a t t e r n o p p o s i t e to p r e f e r e n c e r e v e r s a l , termed an " i n c o n s i s t e n t c h o i c e " . An a d d i t i o n a l 14 s u b j e c t s (22%) were i n d i f f e r e n t between the c h o i c e s when they b i d weeks i n h o s p i t a l f o r them, but a l l of these s u b j e c t s i d e n t i f i e d a p r e f e r e n c e between the o p t i o n s when asked to choose one. Only one s u b j e c t was i n d i f f e r e n t between the o p t i o n s when he had to choose between them, alth o u g h he p r e f e r r e d * A' when b i d d i n g . 92 The r e s u l t s of these q u e s t i o n s demonstrated a t r e n d toward the h i g h p r o b a b i l i t y outcome. In a l l , 42 s u b j e c t s (66%) chose 'A' when asked to choose a treatment, a l t h o u g h the i n i t i a l b i d s f o r 'A' and *B' were w i d e l y d i s p e r s e d (from 1 week to 52 weeks). When d i a g n o s t i c groups were compared, the p a t t e r n s of response were most s i m i l a r between the h e a l t h y s u b j e c t s and the hea r t d i s e a s e c o n t r o l p a t i e n t s . The h e a l t h y s u b j e c t s (n=15) e x h i b i t e d p r e f e r e n c e r e v e r s a l 20% of the time, w h i l e h e a r t d i s e a s e c o n t r o l s (n=20) e x h i b i t e d i t 35% of the time. Among those p a t i e n t s w i t h p a i n and d i s a b i l i t y , o n l y 7% of p a t i e n t s w i t h m i l d angina (n=15) demonstrated p r e f e r e n c e r e v e r s a l and none of the p a t i e n t s w i t h severe angina (n=14) d i d . These two groups had the l a r g e s t p r o p o r t i o n of s u b j e c t s b i d d i n g f o r , and a c t u a l l y c h o o s i n g , e i t h e r 'A' or 'B'. T h i s was an u n a n t i c i p a t e d o c c u r - rence t h a t c o u l d have been due to the s m a l l sample s i z e . When asked to t a l k about t h e i r c h o i c e s , p a t i e n t s w i t h s e v e r e angina seemed r e a l i s t i c about t h e i r f u t u r e h e a l t h . One-half of the p a t i e n t s i n t h i s group had a l r e a d y r e c e i v e d a coronary a r t e r y bypass g r a f t . P a t i e n t s choosing A>B on both the b i d and the c h o i c e s t a t e d t h a t t h e i r f o c u s was on the ' c e r t a i n ' q u a l i t i e s of a 98% chance of no more p a i n . Those p a t i e n t s choosing B>A on both the b i d and the c h o i c e s a i d t h a t an e i g h t year p e r i o d of pa i n r e l i e f was an a t t r a c t i v e g a i n because i t would l i k e l y be as long as t h e i r expected l i f e t i m e . 93 S e v e r a l h e a l t h y s u b j e c t s and h e a r t d i s e a s e c o n t r o l p a t i e n t s who demonstrated p r e f e r e n c e r e v e r s a l d e s c r i b e d t h e i r reasons f o r making a treatment c h o i c e s t a t i n g t h a t they were w i l l i n g to b i d more weeks i n h o s p i t a l f o r treatment *B' because i f i t d i d n ' t p r o v i d e p a i n r e l i e f , they would s u b s e q u e n t l y take 'A' w i t h the h i g h p r o b a b i l i t y of two years w i t h p a i n r e l i e f . These s u b j e c t s were reminded t h a t a f a l l - b a c k p o s i t i o n was not a v a i l a b l e under the c o n s t r a i n t s of the q u e s t i o n . 4.0. Framing: The F o r m u l a t i o n E f f e c t Research s t u d i e s i n s e v e r a l f i e l d s of d e c i s i o n making have demonstrated the i n f l u e n c e of framing b i a s . T h i s b i a s occurs because the wording of a q u e s t i o n has the p o t e n t i a l to a l t e r a s u b j e c t ' s response. Kahneman and Tversky (1984, p. 16) suggest t h a t "A p h y s i c i a n ... c o u l d i n f l u e n c e the d e c i s i o n made by the p a t i e n t ... merely by the framing of outcomes and c o n t i n g e n c i e s . " McNeil e t . al.(1982) demonstrated the e f f e c t s of framing w i t h d i f f e r e n t s c e n a r i o s and d e s c r i p t i o n s of treatment outcomes: f i r s t , i n terms of p e r c e n t m o r t a l i t y , and second, as average years of l i f e of s u r v i v a l a f t e r treatment. The study by McNeil e t . a l . (1982) used 238 male p a t i e n t s i n an ambulatory s e t t i n g , 424 r a d i o l o g i s t s and 491 graduate s t u d e n t s i n b u s i n e s s s c h o o l as s u b j e c t s f o r a framing t e s t . Here i s the q u e s t i o n from the " m o r t a l i t y frame". 94 Of 100 people having s u r g e r y , 10 w i l l d i e d u r i n g treatment, 32 w i l l have d i e d by 1 year, and 66 w i l l have d i e d by 5 y e a r s . Of 100 people having r a d i a t i o n therapy, none w i l l d i e d u r i n g treatment, 23 w i l l d i e by 1 y e a r , and 78 w i l l d i e by 5 y e a r s . Which treatment would you p r e f e r ? The a l t e r n a t i v e way of framing of t h i s q u e s t i o n , c a l l e d the " s u r v i v a l frame", asked s u b j e c t s to choose a treatment when s u r g e r y o f f e r e d an average l i f e expectancy of 6.1 years and r a d i a t i o n o f f e r e d an average l i f e expectancy of 4.7 y e a r s . R a d i a t i o n was p r e f e r r e d 42% of the time i n the m o r t a l i t y frame, and 25% of the time i n the s u r v i v a l (years of l i f e ) frame. The m a j o r i t y of s u b j e c t s i n both cases e l e c t e d s u r g e r y . No lung cancer p a t i e n t s p a r t i c i p a t e d i n t h i s s t udy. Kahneman and Tversky (1984, p. 343) have d e s c r i b e d framing q u e s t i o n s t h a t v i o l a t e i n v a r i a n c e as f o l l o w s : Imagine t h a t the U.S. i s p r e p a r i n g f o r the outbreak of an unusual A s i a n d i s e a s e , which i s expected to k i l l 600 p e o p l e . Two a l t e r n a t i v e programs to combat the d i s e a s e have been proposed. Assume t h a t the exact s c i e n t i f i c e s t i m a t e s of the consequences of the programs a r e : Problem 1: (152 s u b j e c t s ) I f Program A i s adopted, 200 people w i l l be saved. [72% chose A] I f Program B i s adopted, t h e r e i s a o n e - t h i r d p r o b a b i l i t y t h a t 600 people w i l l be saved and a t w o - t h i r d s p r o b a b i l i t y t h at no people w i l l be saved. [28% chose B] ..The same cover s t o r y i s f o l l o w e d by a d i f f e r e n t d e s c r i p t i o n of the p r o s p e c t s a s s o c i a t e d w i t h the two programs: Problem 2 (155 s u b j e c t s ) : I f Program C i s adopted 400 people w i l l d i e . [22% chose C] I f Program D i s adopted, t h e r e i s a o n e - t h i r d p r o b a b i l i t y t h a t nobody w i l l d i e and a t w o - t h i r d s p r o b a b i l i t y t h a t 600 people w i l l d i e . [78% chose D] 95 S e v e r a l d e p a r t u r e s from these r e p o r t e d t e c h n i q u e s of demon- s t r a t i n g framing were made i n the pr e s e n t study. F i r s t , m e d i c a l terms t h a t c o u l d induce p r e c o n c e p t i o n s i n p a t i e n t s were a v o i d e d . The words s u r g e r y , drugs, and a n g i o p l a s t y were not used as i d e n t i f y i n g terms. The reason f o r t h i s change was drawn from the McNeil e t . a l . (1978) f i n d i n g t h a t p a t i e n t s may have a p a r t i c u l a r f e a r of treatment such as r a d i a t i o n and a l l o w t h e i r p r e c o n c e p t i o n s to generate avoidance behaviour even i f the outcomes were p r e f e r r e d by the p a t i e n t w i t h an u n i d e n t i f i e d t reatment. Second, the q u e s t i o n s were kept as s i m i l a r as p o s s i b l e , a l t e r i n g o n l y the order of the outcomes. P a t i e n t s were encouraged to see what the q u e s t i o n i m p l i e d by u s i n g v i s u a l a i d s t h a t d e s c r i b e d the treatment outcome. The same v i s u a l a i d was used f o r both q u e s t i o n s (see Appendix I I ) . The reason f o r such a simple t e s t of the e f f e c t of the f o r m u l a t i o n of the q u e s t i o n was to determine whether a s m a l l v a r i a t i o n c o u l d cause s u b j e c t s to a l t e r t h e i r p r e f e r e n c e s f o r a treatment. The framing q u e s t i o n s were as f o l l o w s : (a) The " w e l l n e s s frame". A f t e r a treatment f o r angina, some p a t i e n t s have no p a i n w h i l e some p a t i e n t s have p a i n twice as o f t e n as b e f o r e the treatment. The numbers below are chances t h a t the treatment w i l l e l i m i n a t e angina p a i n f o r 2 y e a r s . Which of these groups would be accep- t a b l e to you? 96 chance of no p a i n p a i n twice as o f t e n yes / no A. 90% 10% B. 70% 30% C. 50% 50% D. 30% 70% E. 10% 90% I f A i s not a good enough 'chance' f o r improvement, what chance would be a c c e p t a b l e ? I f E i s a c c e p t a b l e , what lower chance i s not a c c e p t a b l e ? (b) The " i l l n e s s frame". A f t e r a treatment f o r a n g i n a , some p a t i e n t s have p a i n twice as o f t e n as b e f o r e the treatment, w h i l e some p a t i e n t s have no more p a i n . The numbers below are chances t h a t the treatment w i l l cause p a i n twice as o f t e n f o r some p a t i e n t s . Which of these groups would be a c c e p t a b l e to you? chance of p a i n t w i c e as o f t e n no p a i n yes / no A. 10% 90% B. 30% 70% C. 50% 50% D. 70% 30% E. 90% 10% 4.1. Framing E f f e c t s Framing was c o n s i d e r e d p r e s e n t when the p a t i e n t changed h i s / h e r c h o i c e of a treatment by one l e v e l i n e i t h e r d i r e c t i o n . That i s , i f a more c o n s e r v a t i v e treatment was chosen ( l e v e l B was p r e f e r r e d i n the " w e l l n e s s " frame and l e v e l A was p r e f e r r e d i n the " i l l n e s s " frame), framing was c o n s i d e r e d to be p r e s e n t . S u b j e c t s were c o n s i d e r e d to be c o n s i s t e n t i f the framing of the q u e s t i o n d i d not i n f l u e n c e t h e i r c h o i c e . Framing was a l s o c o n s i d e r e d to be p r e s e n t i f the i l l n e s s frame caused a l e s s 97 c o n s e r v a t i v e c h o i c e than the w e l l n e s s frame. S u b j e c t s were a l s o p e r m i t t e d to a v o i d making a c h o i c e by s t a t i n g t h a t no treatment was "good enough" ( o f f e r e d a h i g h p r o b a b i l i t y of improvement), and to extend the range of treatment outcomes o f f e r e d by s t a t i n g an a d d i t i o n a l p r o b a b i l i t y of p a i n r e l i e f t h a t would be good enough. The q u e s t i o n s used i n the study of p a t i e n t s w i t h h e a r t d i s e a s e d i f f e r from other framing s t u d i e s because they allowed p a t i e n t s to c o n t i n u e choosing treatments u n t i l they reached a l e v e l of u n a c c e p t a b l e p r o b a b i l i t i e s of p a i n r e l i e f , as determined by the p a t i e n t . Other s t u d i e s have o f f e r e d s u b j e c t s two a l t e r n a t i v e s o n l y . T a b l e 3.2. Framing E f f e c t s f o r A l l Heart Study S u b j e c t s , n=64 diagnos i s / outcome framing more l e s s same t o t a l h e a l t h y 3 4 8 15 h e a r t c o n t r o l 9 3 8 20 m i l d angina 6 3 6 15 severe angina 6 5 3 14 TOTAL 24 15 25 64 Note: 25 p a t i e n t s and s u b j e c t s were c o n s i s t e n t i n t h e i r c h o i c e s , i n c l u d i n g 2 p a t i e n t s who were c o n s i s t e n t i n t h e i r r e f u s a l to take any treatment. 98 4.3. D i s c u s s i o n of Framing Tab l e 3.2 shows t h a t 39 out of 64 p a t i e n t s demonstrated v u l n e r a b i l i t y to framing: 24 took a more c o n s e r v a t i v e treatment w i t h an " i l l n e s s frame" than w i t h a "w e l l n e s s frame" w h i l e 15 accepted a l e s s c o n s e r v a t i v e treatment under the same c o n d i t i o n s . A d e t a i l e d e v a l u a t i o n of the q u e s t i o n n a i r e s of the p a t i e n t s not making a c h o i c e showed t h a t these p a t i e n t s made comments l i k e : "I would take whichever treatment my d o c t o r wanted me to t a k e . " Or, "I can't d e c i d e because I don't have any a d v i c e . " In p r e v i o u s r e p o r t s of s t u d i e s p r o b i n g the framing b i a s , s u b j e c t s were c o n s t r a i n e d by two c h o i c e s and e v a l u a t i o n of some of the e f f e c t s found here c o u l d not be made. 4.4. D i s c u s s i o n of D i a g n o s t i c Groups Framing appeared to a f f e c t a l l d i a g n o s t i c groups t o a s i m i l a r e x t e n t . Seven of 15 (47%) h e a l t h y s u b j e c t s e x h i b i t e d f r a m i n g e f f e c t s . Among h e a r t d i s e a s e c o n t r o l p a t i e n t s , 12 of 20 (60%) e x h i b i t e d framing w h i l e nine p a t i e n t s out of 15 (60%) wi t h m i l d angina demonstrated i t . For p a t i e n t s w i t h severe angina, 11 out of 14 (79%) were i n f l u e n c e d by the framing of the q u e s t i o n . These d i f f e r e n c e s were not s t a t i s t i c a l l y s i g n i f i c a n t a l t h o u g h the power to d e t e c t a d i f f e r e n c e was low. The p a t i e n t s w i t h the most s e r i o u s p a i n and d i s a b i l i t y were the group most v u l n e r a b l e to the d e c i s i o n b i a s . Of c o n s i d e r a b l e 99 i n t e r e s t was the number of p a t i e n t s who remained c o n s i s t e n t and appeared not to be i n f l u e n c e d by f r a m i n g . Among h e a l t h y s u b j e c t s , e i g h t of 15 (53%) were c o n s i s t e n t . The group of p a t i e n t s who were h e a r t d i s e a s e c o n t r o l s had seven of 20 (35%) c o n s i s t e n t members. P a t i e n t s w i t h m i l d angina had s i x of 15 members c o n s i s t e n t w h i l e of those 14 p a t i e n t s w i t h severe angina, o n l y two (14%) were c o n s i s t e n t . The m a j o r i t y of t h i s l a s t group were i n f l u e n c e d by fr a m i n g . Again, i t was d i f f i c u l t to deny t h a t p a t i e n t s w i t h severe p a i n and d i s a b i l i t y were not i n f l u e n c e d by t h i s d e c i s i o n b i a s more than h e a l t h y or o n l y moderately i l l p e r sons. 4.4. C o n c l u s i o n s The focus of the framing q u e s t i o n s i n t h i s r e s e a r c h was not to demonstrate framing a l o n e , but to demonstrate other p e r i p h e r a l e f f e c t s of the f o r m u l a t i o n of a q u e s t i o n . I t was p o s s i b l e w i t h the format used to demonstrate t h a t the wording of the q u e s t i o n caused a number of e f f e c t s . Would p a t i e n t s and s u b j e c t s be induced to change t h e i r p r e f e r e n c e f o r a treatment whose outcome p r o b a b i l i t i e s v a r i e d by more than 20%? Only one p a t i e n t (with s e v e r e angina) was so s t r o n g l y i n f l u e n c e d by the wording of the q u e s t i o n t h a t he chose a treatment outcome with ' i l l n e s s f r a m i n g ' 40% above the treatment w i t h 'wellness f r a m i n g ' . The c l i n i c a l s i g n i f i c a n c e of t h i s demonstration of framing i s drawn from the f a c t t h a t almost twice as many s u b j e c t s were 100 v u l n e r a b l e to framing as were c o n s i s t e n t . These s u b j e c t s a l s o had a v i s u a l a i d c l e a r l y r e p r e s e n t i n g the p r o b a b i l i t i e s of improved h e a l t h i n both the w e l l n e s s frame and the i l l n e s s frame. F u r t h e r r e s e a r c h i n t o i d e n t i f y i n g how p a t i e n t s anchor on e i t h e r the f i r s t or l a s t t h i n g a p h y s i c i a n says would improve the u n d e r s t a n d i n g of framing as a b a r r i e r to communication. 5.0. The S u b s t i t u t i o n E f f e c t The s u b s t i t u t i o n axiom of u t i l i t y t h e o r y s t a t e s t h a t i f one c h o i c e (A) i s p r e f e r r e d to a second c h o i c e (B), then any change th a t a f f e c t s both c h o i c e s e q u a l l y s h o u l d not i n f l u e n c e the c h o i c e of A i n p r e f e r e n c e to B. Two q u e s t i o n s i n the p r e s e n t s t u d y attempted to determine whether the s u b s t i t u t i o n e f f e c t h e l d f o r c l i n i c a l d e c i s i o n s i n v o l v i n g r i s k of death as an outcome. The f i r s t q u e s t i o n was e s s e n t i a l l y a r e p l i c a t i o n of the McNeil e t . a l . (1978) study of p r e f e r e n c e s f o r p a t i e n t s with cancer of the l u n g . Heart d i s e a s e p a t i e n t s were o f f e r e d a c h o i c e between a moderate outcome wi t h no r i s k of death and an outcome wi t h g r e a t e r p a i n r e d u c t i o n accompanied by a 5% r i s k of death. To t r y to demonstrate the i n f l u e n c e of the s u b s t i t u t i o n e f f e c t , a 10% r i s k of death was added to both s e t s of outcomes w h i l e s i m u l t a n e o u s l y r e d u c i n g the o t h e r outcomes (pain r e l i e f , or no change) to 90% of t h e i r former l e v e l i n o r d e r to m a i n t a i n the t o t a l p r o b a b i l i t y of outcomes at 100%. The a c t u a l r e s u l t s were rounded to the n e a r e s t 5%, to 101 reduce s u b j e c t c o n f u s i o n . Rounding s m a l l p r o b a b i l i t i e s can cause problems w i t h the f o r m u l a t i o n of an a c c u r a t e demonstration of the s u b s t i t u t i o n e f f e c t i n i t s s t r i c t e s t sense. 1 In a d d i t i o n , t h r e e s e t s of p r o b a b i l i t i e s were o f f e r e d to s u b j e c t s , r a t h e r than the common use of two s e t s . The reason f o r t h i s c h o i c e was due to e f f o r t s to make the d e c i s i o n as r e a l i s t i c as p o s s i b l e . Theory p r e d i c t s t h a t a person c h o o s i n g treatment A i n the f i r s t p a i r of c h o i c e s , should choose treatment A* i n the second p a i r of c h o i c e s (Savage, 1954). The two s e r i e s of c h o i c e s are g i v e n below. S u b s t i t u t i o n e f f e c t , p a r t one: L i s t e d below are some h y p o t h e t i c a l procedures with r i s k s and b e n e f i t s l i s t e d ; which one would you choose? Assume t h a t you cannot have both t r e a t m e n t s . no angina same p a i n r i s k of death treatment A 80% 15% 5% treatment B 60% 40% 0% c h o i c e : A or B or no p r e f e r e n c e I f you chose A, what outcomes would need to be a l t e r e d and by how much to encourage you to choose B? I f you chose B, what outcomes would need to be a l t e r e d and by how much to encourage you to choose A? 1 The rounding of the p r o b a b i l i t i e s i n t h i s example caused the u t i l i t i e s of the outcomes i n the examples chosen to vary by .05. C l i n i c a l s i g n i f i c a n c e and p a t i e n t u n d e r s t a n d i n g was g i v e n p r i o r i t y over mathematical e q u i v a l e n c e i n t h i s q u e s t i o n . 102 S u b s t i t u t i o n e f f e c t , p a r t two These treatment groups have d i f f e r e n t outcomes, which one would you choose? no angina same p a i n r i s k of death treatment A* 70% 15% 15% treatment B* 55% 35% 10% c h o i c e : A* or B* or no p r e f e r e n c e What a s p e c t s d i d you focus on to make your c h o i c e ? The second p a i r of c h o i c e s was f o l l o w e d by a s k i n g the p a t i e n t to s t a t e which outcome was the determinant of the c h o i c e of treatment. Treatment B would l i k e l y have s i g n i f i c a n t a t t r a c t i o n f o r those s u b j e c t s c h o o s i n g treatment A ( r i s k a v e r s e p a t i e n t s ) i n the f i r s t treatment c h o i c e , w h i l e the presence of the r i s k of death as an outcome i n both o p t i o n s of the second p a i r of c h o i c e s may swing the focus onto the p a i n r e l i e f , e ncouraging p a t i e n t s to a l t e r t h e i r c h o i c e from A to B*. In the q u e s t i o n n a i r e , the A* and B* markings were o m i t t e d . Some i n f l u e n c e of the c e r t a i n t y e f f e c t was p r o b a b l y f e l t by p a t i e n t s who s e l e c t c h o i c e B s i n c e the r i s k of death here was z e r o . Option A i s a f a i r l y c l o s e a p p r o x i m a t i o n of the s t a t i s t i c a l outcome of bypass s u r g e r y as r e p o r t e d i n the CASS Study reviewed i n Chapter 1. Option B i s a c l o s e a p p r o x i m a t i o n of the outcome of m e d i c a l therapy f o r coro n a r y a r t e r y d i s e a s e . The data from these q u e s t i o n s were a n a l y s e d i n two groups: h e a l t h y s u b j e c t s f o r whom the d e c i s i o n was h y p o t h e t i c a l , and 103 p a t i e n t s w i t h h e a r t d i s e a s e , f o r whom the d e c i s i o n was r e a l i s t i c . Those s u b j e c t s who were c o n s i s t e n t i n t h e i r c h o i c e s are i d e n t i - f i e d i n the A,A* c e l l s and the B,B* c e l l s on the main d i a g o n a l . S u b j e c t s who v i o l a t e d the s u b s t i t u t i o n axiom a r e i d e n t i f i e d i n the B,A* c e l l s i n the lower l e f t c e l l of each t a b l e . The second q u e s t i o n employed a s e n s i t i v i t y a n a l y s i s to determine a t r a d e o f f p o i n t f o r p a t i e n t s who s e l e c t e d treatment B. P a t i e n t s were asked how much b e t t e r treatment A needed to be ( i n terms of time f r e e from symptoms) i n order f o r them to choose i t . T h i s a n a l y s i s was a l s o used to i d e n t i f y whether t h e r e was c o n s i d e r a b l e r e s i s t a n c e among p a t i e n t s to assuming a ' r i s k ' a f t e r a modest outcome ' f o r s u r e ' had been chosen. T a b l e 3.3. S u b s t i t u t i o n E f f e c t : A l l Respondents, n=100 second c h o i c e f i r s t A* B* c h o i c e A 47 8 B # 19 26 notes: ( a ) p e r c e n t s equal counts when count equals 100. (b) # i d e n t i f i e s v i o l a t i o n of the s u b s t i t u t i o n axiom (c) Kappa of .44 i n d i c a t e s poor i n t r a s u b j e c t agreement. 104 Tabl e 3.4. S u b s t i t u t i o n E f f e c t : Heart D i s e a s e Groups, n=49 second c h o i c e f i r s t A* B* c h o i c e A 29 (59 .2%) 1 (2.0%) B #13 (20 .6%) 12(19.0%) notes: # i d e n t i f i e s v i o l a t i o n of the s u b s t i t u t i o n axiom T a b l e 3.5. S u b s t i t u t i o n E f f e c t f o r H e a l t h y S u b j e c t s and H o s p i t a l A d m i n i s t r a t o r s , n=51 second c h o i c e f i r s t c h o i c e A* B* A 18 (34 .6%) 7 (13.5%) B # 9(17 .3%) 17 (32.7%) note: # i d e n t i f i e s v i o l a t i o n of the s u b s t i t u t i o n axiom. 5.1. D i s c u s s i o n I t i s i n t e r e s t i n g to note t h a t h e a r t d i s e a s e p a t i e n t s were more c o n s i s t e n t l y r i s k - s e e k i n g than the group of h e a l t h y a d u l t s and h o s p i t a l a d m i n i s t r a t o r s . Both groups demonstrated almost the same r a t e of v i o l a t i o n of the s u b s t i t u t i o n axiom: 21% f o r the p a t i e n t s , and 17% f o r the h e a l t h y s u b j e c t s . When the s u b j e c t s making a c o n s i s t e n t c h o i c e were compared by h e a l t h s t a t u s , no 105 s i g n i f i c a n t d i f f e r e n c e (p=.64) was found between h e a l t h y s u b j e c t s and h e a r t d i s e a s e p a t i e n t s . A n o t i c e a b l e d i f f e r e n c e between these groups was t h a t 14% of the h e a l t h y s u b j e c t s made an i n c o n s i s t e n t c h o i c e i n the o p p o s i t e d i r e c t i o n to v i o l a t i o n of the s u b s t i t u t i o n axiom, w h i l e o n l y 2% of the p a t i e n t s w i t h h e a r t d i s e a s e made t h i s c h o i c e . Comments from t h i s group added to the u n d e r s t a n d i n g of these r e s p o n s e s . A t y p i c a l v e r b a l response from a p a t i e n t w i t h h e a r t d i s e a s e was "I chose A i n the f i r s t q u e s t i o n because the outcome was b e t t e r , but I c o u l d not choose A* i n the second q u e s t i o n because the l e v e l of r i s k was u n a c c e p t a b l e . " A n a l y s i s of comments of h e a l t h y s u b j e c t s and p a t i e n t s suggests t h a t s u b j e c t s f o c u s e d on p a i n r e l i e f e x c l u s i v e l y when they chose A and A*, and they f o c u s e d on r i s k of death e x c l u s i v e l y when they chose B and B*. Those who v i o l a t e d the s u b s t i t u t i o n axiom seemed to be drawn to do so when t h e i r i n t e r e s t i n a v o i d i n g r i s k of death was d i s t r a c t e d by both treatments having a r i s k of death (10% and 15%). Some p a t i e n t s c l a i m e d t h a t these two l e v e l s were " s i m i l a r " . They e x p l a i n e d t h a t when the r i s k of death was s i m i l a r , they f o c u s e d on p a i n r e l i e f i n order to make a c h o i c e . These comments from s u b j e c t s support the a s s e r t i o n of MacCrimmon (1974) t h a t s u b j e c t s tend to make c h o i c e s by comparing p a i r s of a t t r i b u t e s . 106 6.0. Asymmetric C h o i c e : Choices i n the Domain of Gains or Losses U t i l i t y t h e o r y s t a t e s t h a t the v a l u e of wealth (or i n t h i s study, h e a l t h ) i s determined by the f i n a l a s s e t p o s i t i o n , or f i n a l s t a t e of h e a l t h , not by the p a r t i c u l a r l i f e c i r c u m s t a n c e of the i n d i v i d u a l . O b s e r v a t i o n s of a c t u a l d e c i s i o n making behaviour do not always support the t h e o r y . MacCrimmon (1974, p. 474) s t a t e s t h a t " r i s k t a k i n g may not be a g e n e r a l p e r s o n a l i t y t r a i t but may be v e r y dependent on the s i t u a t i o n the d e c i s i o n maker i s i n . " T h e r e f o r e , a c t u a l l y f a c i n g a l o s s may p l a c e a d e c i s i o n maker i n a s i t u a t i o n i n which r i s k t a k i n g behaviour i s demonstrated. An a l t e r n a t i v e p r o p o s a l f o r u n d e r s t a n d i n g r i s k y c h o i c e has been c a l l e d 'prospect t h e o r y ' (Kahneman and Tversky, 1979). One h y p o t h e s i s of p r o s p e c t t h e o r y addresses the o b s e r v a t i o n t h a t changes i n wealth from some a r b i t r a r y r e f e r e n c e p o i n t determine d e c i s i o n s . In other words, d e c i s i o n makers have a s u b j e c t i v e v a l u e of a l o s s or a g a i n . The u t i l i t y f u n c t i o n appears s t e e p e r f o r l o s s e s than g a i n s , d e s c r i b i n g the more i n t e n s e f e e l i n g s a s s o c i a t e d w i t h a l o s s than w i t h a g a i n f o r the same magnitude. T h a l e r (1980, p. 42) has summarized the f i n d i n g s of the above s t u d i e s as f o l l o w s : "... gains a r e t r e a t e d d i f f e r e n t l y than l o s s e s . Except f o r v e r y s m a l l p r o b a b i l i t i e s , r i s k s e e k i n g i s observed f o r l o s s e s w h i l e r i s k a v e r s i o n i s observed f o r g a i n s . " T h i s g e n e r a l i z a t i o n i s drawn from a number of r e s u l t s i n c l u d i n g the f o l l o w i n g two examples from Kahneman and Tversky (1979). 107 Both examples o f f e r i d e n t i c a l f i n a l s t a t e s of w e a l t h . Problem 1: In a d d i t i o n to whatever you own you have been g i v e n $1,000. You are now asked to choose between: A: a 50% chance of $1,000 B: $500 f o r sure In t h i s problem, 70 s u b j e c t s were t e s t e d ; 16% chose A and 84% chose B. Problem 2: In a d d i t i o n to whatever you own, you have been g i v e n $2,000. You are now asked to choose between: C: a 50% chance of l o s i n g $1,000 0: l o s i n g $500 f o r s u r e . In t h i s problem, 68 s u b j e c t s were t e s t e d ; 69% chose C and 31% chose D. To t e s t whether u t i l i t y t h e o r y d e s c r i b e d c h o i c e b e h a v i o u r , or whether changes i n a s s e t p o s i t i o n were more important, p a t i e n t s i n the p r e s e n t study were asked to make treatment c h o i c e s where changes i n a s s e t p o s i t i o n over e i t h e r gains or l o s s e s c o u l d cause d i f f e r e n t b e h a v i o u r . The q u e s t i o n s used i n the h e a r t study to t e s t p a t i e n t ' s s u b j e c t i v e v a l u e of gains or l o s s e s i n r e l a t i o n to s t a t e s of h e a l t h are s e t out below. (a) Choosing between g a i n s . Choose between the f o l l o w i n g two t r e a t m e n t s : treatment A: A 50% chance of no angina p a i n a f t e r any amount of e x e r c i s e , and a 50% chance of p a i n the same as i t i s now; treatment B: Twice as much e x e r c i s e f o r s u r e w i t h no angina p a i n . 108 (b) Choosing between l o s s e s . Choose between the f o l l o w i n g two t r e a t m e n t s . treatment A: A 50% chance of no angina p a i n a f t e r any amount of e x e r c i s e , and a 50% chance of not b e i n g a b l e to e x e r c i s e a t a l l ; treatment B: A c e r t a i n l o s s of 1/2 of your c u r r e n t e x e r c i s e time b e f o r e angina p a i n the same as i t i s now. P a t i e n t s were a l s o asked: How long can you e x e r c i s e now b e f o r e angina pain? How many b l o c k s can you walk without angina? The study q u e s t i o n s were b i a s e d i n f a v o u r of e l i c i t i n g a c h o i c e s i m i l a r to those d e s c r i b e d i n p r o s p e c t t h e o r y . T h i s t h e o r y s t a t e s t h a t s u b j e c t s w i l l p r e f e r a modest outcome f o r sure (and are t h e r e f o r e r i s k averse) i n the domain of g a i n s but p r e f e r a r i s k i n the domain of l o s s e s . The l o s s q u e s t i o n was b i a s e d by improving the 'gamble' of the l o s s from a 50/50 chance of the s t a t u s quo or a l o s s (as i n the Kahneman and Tversky (1979) q u e s t i o n s ) , to a 50/50 chance of a g a i n or a l o s s . Should s u b j e c t s demonstrate r i s k a v e r s i o n i n the domain of l o s s e s , the study r e s u l t s would suggest a demonstration of u t i l i t y t h e o r y r a t h e r than p r o s p e c t t h e o r y . I f s u b j e c t s were r i s k s e e k i n g i n t h i s domain, p r o s p e c t t h e o r y would not n e c e s s a r i l y be supported because the 50/50 gamble i n the h e a r t study was somewhat b e t t e r than the gamble posed i n the t e s t s of the t h e o r y by Kahneman and Tversky (1979). P a t i e n t s and h e a l t h y s u b j e c t s were asked to make two c o n s e c u t i v e c h o i c e s , one r e p l i c a t i n g the domain of gains and the 109 o t h e r r e p l i c a t i n g the domain of l o s s e s . A l l p a t i e n t s were reminded of t h e i r c u r r e n t l e v e l of symptoms w h i l e h e a l t h y s u b j e c t s were asked to imagine a l e v e l of e x e r c i s e t o l e r a n c e of o n e - h a l f hour. For v e r y i l l p a t i e n t s , e x e r c i s e time was minimal, and f o r some p a t i e n t s , n o n e x i s t a n t . T h i s f a c t o r may have had an i n f l u e n c e on the unique p a t t e r n of responses found i n the group of p a t i e n t s w i t h severe a n g i n a . The c h o i c e s made i n the f i r s t q u e s t i o n were r e p r e s e n t e d by the ' g a i n b i d ' rows, w h i l e the c h o i c e s made on the second q u e s t i o n were r e p r e s e n t e d by the ' l o s s b i d ' columns. In T a b l e s 3.6 and 3.7, the f i r s t number l i s t e d i n each c e l l i s the number of s u b j e c t s making the combined c h o i c e . The second number i s the p r o p o r t i o n of the t o t a l number of s u b j e c t s found i n each c e l l . Row t o t a l s and column t o t a l s are l a b e l l e d . T a b l e 3.6. Asymmetric Choice f o r A l l Heart Study P a t i e n t s , n=49 l o s s b i d A' B' t o t a l A 5 9 14 g a i n b i d 10.2% 18.4% 28.6% B 9 26 35 18.4% 53.1% 71.5% 14 35 49 t o t a l 28.6% 71.5% 100.0% 110 Ta b l e 3.7. Asymmetric Choice f o r A l l Heal t h y S u b j e c t s , n=51 l o s s b i d A' B' t o t a l A 14 8 22 g a i n b i d 27.5% 15.7% 43.2% B 15 14 29 29.4% 27.5% 56.9% t o t a l 29 22 51 56.9% 43.2% 100.0% 6.1. D i s c u s s i o n Across a l l 100 s u b j e c t s , 36% of s u b j e c t s were r i s k - s e e k i n g on the f i r s t c h o i c e ( g a i n s ) , w h i l e the m a j o r i t y , 64%, were r i s k a v e r s e . When a comparison was made of r i s k a v e r s e c h o i c e s (the B,B' c h o i c e ) among h e a l t h y s u b j e c t s and p a t i e n t s w i t h h e a r t d i s e a s e , the groups were found to be s i g n i f i c a n t l y d i f f e r e n t (p=.016). On the q u e s t i o n r e l a t i n g to a l o s s s i t u a t i o n , 57% were r i s k a v e r s e w h i l e 43% of the s u b j e c t s were r i s k - s e e k i n g , l e s s than would be expected w i t h a money q u e s t i o n of the same nature. The s i g n i f i c a n t d e p a r t u r e from p r o s p e c t t h e o r y i s the 57% of s u b j e c t s who are r i s k - a v e r s e i n t h i s s i t u a t i o n . In f a c t , 40% were r i s k a v e r s e i n both q u e s t i o n s . Three v e r y i n t e r e s t i n g trends were e s t a b l i s h e d i n these d a t a . F i r s t , the upper r i g h t - h a n d c e l l of each t a b l e p r e s e n t s I l l the responses to the two q u e s t i o n s as p r e d i c t e d by pr o s p e c t t h e o r y . The h e a l t h y s u b j e c t s and p a t i e n t s r e p r e s e n t e d by t h i s c e l l have responded i n a r i s k a v e r s e way to the f i r s t q u e s t i o n and i n a r i s k s e e k i n g way to the second q u e s t i o n . Of the h e a l t h y a d u l t s u b j e c t s (n=15), o n e - t h i r d responded i n the p a t t e r n p r e d i c t e d . In both the h e a r t d i s e a s e c o n t r o l s (n=20) and the p a t i e n t s w i t h m i l d angina (n=15), 20% made a r i s k - a v e r s e c h o i c e i n the g a i n q u e s t i o n and a r i s k - s e e k i n g c h o i c e i n the l o s s q u e s t i o n . However, of the 14 very i l l p a t i e n t s (those w i t h severe a n g i n a , n=14), o n l y 14% responded as p r e d i c t e d by p r o s p e c t t h e o r y . T h i s evidence o f f e r s some support to the i n i t i a l q u e s t i o n posed by the study t h a t p a i n and d i s a b i l i t y i n f l u e n c e d e c i s i o n s t r a t e g i e s - i n c l u d i n g e r r o r s of judgement. Less than h a l f as many v e r y i l l p a t i e n t s as h e a l t h y s u b j e c t s demonstrated the p a t t e r n p r e d i c t e d by p r o s p e c t t h e o r y . P r e v i o u s r e s e a r c h on asymmetric c h o i c e behaviour has been conducted p r i m a r i l y on young, h e a l t h y s u b j e c t s u s i n g money b e t s . The h e a r t study e v i d e n c e w i t h s u b j e c t s demonstrating o t h e r demographic c h a r a c t e r - i s t i c s suggests t h a t the accepted t h e o r y may not be g e n e r a l i z a b l e e s p e c i a l l y i f c h o i c e s used are h y p o t h e t i c a l . The second i n t e r e s t i n g f i n d i n g i s t h a t a d i f f e r e n t per cent of h e a l t h y s u b j e c t s and p a t i e n t s were r i s k a v e r s e on both c h o i - c e s . T h i s c h o i c e i s d i s p l a y e d i n the lower r i g h t - h a n d c e l l i n Tables 3.6 and 3.7. Among h e a l t h y s u b j e c t s , 28% demonstrated t h i s c h o i c e p a t t e r n w h i l e 53% of h e a r t d i s e a s e p a t i e n t s e x h i b i t e d 112 i t . The t h i r d i n t e r e s t i n g f i n d i n g i s t h a t the most s e v e r e l y i l l p a t i e n t s are the most c o n s i s t e n t l y r i s k - s e e k i n g over both c h o i c e s . T h i s group chose the r i s k y outcome 29% of the time w h i l e the o t h e r groups chose these outcomes o n l y 7% of the time ( h e a l t h y and m i l d a n g i n a ) , or not at a l l (heart d i s e a s e con- t r o l s ) . To understand the thought p r o c e s s e s u n d e r l y i n g t h i s p a t t e r n , an a n a l y s i s of p a t i e n t ' s comments on t h i s q u e s t i o n was conducted. A p a t i e n t w i t h s e v e r e angina commented: "I would choose the 50/50 gamble i n q u e s t i o n (a) because my e x e r c i s e time i s so s h o r t now t h a t twice n o t h i n g i s s t i l l r e a l l y n o t h i n g . " S i m i l a r reasons were apparent f o r c h o i c e s on the second ques- t i o n . One p a t i e n t r e p l i e d : "I would be g l a d to r i s k not b e i n g a b l e to e x e r c i s e a t a l l f o r a 50% chance of freedom from t h i s p a i n . " The c h o i c e t h a t c r e a t e d the b i g g e s t d i f f e r e n c e between the groups was t h i s r i s k s e e k i n g c h o i c e by s e v e r e l y i l l p a t i e n t s on q u e s t i o n ( a ) . I t i s almost the complete r e v e r s e of the p a t t e r n demonstrated by h e a l t h y s u b j e c t s . T h i s i s a t r e n d worth f u r t h e r i n v e s t i g a t i o n . 6.2. C o n c l u s i o n s The data c o l l e c t e d from the 64 h e a r t study s u b j e c t s and 36 h o s p i t a l a d m i n i s t r a t o r s i n t h i s study d i d not s t r o n g l y support the o b s e r v a t i o n s of asymmetric c h o i c e as i t has been d e s c r i b e d . Only 24% of a l l respondents (n=100) were r i s k a v e r s e i n the domain of g a i n s and r i s k s e e k i n g i n the domain of l o s s e s . At 113 l e a s t h a l f of every group except h o s p i t a l a d m i n i s t r a t o r s were r i s k a v e r s e over both c h o i c e s ; 20% of a d m i n i s t r a t o r s demonstrated t h i s p a t t e r n . The h e a r t study p a t i e n t s g e n e r a l l y p r e f e r r e d a modest outcome f o r sure r a t h e r than a 50/50 gamble between a v e r y good and a ve r y poor outcome or a ve r y good outcome and the s t a t u s quo. The e x c e p t i o n to t h i s g e n e r a l f i n d i n g was r i s k s e e k i n g over gains and l o s s e s by p a t i e n t s w i t h s e v e r e a n g i n a . R i s k - s e e k i n g c h o i c e s may have been encouraged by the p a i n and d i s a b i l i t y e x p e r i e n c e d by p a t i e n t s w i t h a n g i n a . For many p a t i e n t s , even the s t a t u s quo (as i t i s d e s c r i b e d i n the f i r s t q u e s t i o n ) i s a poor outcome because i t i s based on c u r r e n t p a i n and d i s a b i l i t y . F u r t h e r d i s c u s s i o n of the r i s k s e e k i n g behaviour of the v e r y i l l p a t i e n t s appears i n Chapter 4. P h y s i c i a n s and oth e r h e a l t h p r o f e s s i o n a l s t r e a t i n g those p a t i e n t s who must make a treatment c h o i c e can bes t meet the needs of the p a t i e n t by a p p l y i n g s t r a t e g i e s s i m i l a r to those j u s t d e s c r i b e d t h a t d i f f e r e n t i a t e r i s k - s e e k i n g and r i s k - a v e r s e p a t i e n t s . Although the most s e r i o u s l y i l l p a t i e n t s i n t h i s study were the most c o n s i s t e n t l y r i s k - s e e k i n g , the d i f f e r e n c e between p a t i e n t groups was not s t a t i s t i c a l l y s i g n i f i c a n t . 7.0. W i l l i n g n e s s to Pay E f f o r t s have been made by economists to adapt market s t r a t e g i e s to understand the v a l u e to consumers of h e a l t h c a r e 114 consumption i n a s i t u a t i o n where t h e r e i s no c o s t to the p a t i e n t at the p o i n t of s e r v i c e d e l i v e r y . Mendeloff (1983, p. 575) has s t a t e d t h a t " i n a market c o n t e x t we expect people to pay more to reduce r i s k s t h a t they do f a c e than r i s k s they do not f a c e . " One a p p l i c a t i o n of these e f f o r t s has been a measure of ' w i l l i n g n e s s - to-pay' f o r h e a l t h care s e r v i c e s , e s p e c i a l l y when those s e r v i c e s have been p a i d f o r by e i t h e r p r i v a t e or p u b l i c i n s u r a n c e . W i l l i n g n e s s - t o - p a y may be viewed as a measure of the v a l u e of the s e r v i c e to the consumer or a t e c h n i q u e of e x p l o r i n g " i n d i v i d u a l v a l u a t i o n s of p r o b a b i l i t i e s of death" (Evans, 1984, p. 255). S e v e r a l problems e x i s t w i t h t h i s measure, not the l e a s t of which i s t h a t consumers may not be the b e s t judges of what and how much h e a l t h c a r e they should consume (Evans, 1984). Consumption, t h e r e f o r e , i s u s u a l l y dependent on the agent's ( u s u a l l y the d o c t o r ' s ) d e t e r m i n a t i o n of the p a t i e n t ' s need f o r care which may not r e f l e c t the value of h e a l t h care to the p a t i e n t . Problems wi t h w i l l i n g n e s s - t o - p a y are a l s o due to the f a c t t h a t " v a l u a t i o n s are not l i n e a r " (Evans, 1984, p. 256). A l o n g l i f e appears to have l e s s v a l u e t h a t a s h o r t one. In a d d i t i o n , these measures are u n i - d i m e n s i o n a l and do not take i n t o account the v a l u e of an i n d i v i d u a l ' s l i f e to h i s / h e r f a m i l y and f r i e n d s . G e n e r a l l y , w i l l i n g n e s s - t o - p a y measures u t i l i z e a p r o p o r t i o n of income or net worth as a means of e s t a b l i s h i n g the v a l u e of a 115 h e a l t h c a r e s e r v i c e . 3 M e d e l o f f (1983) c a u t i o n s t h a t q u e s t i o n s a s k i n g what p e o p l e ought to pay f o r a h e a l t h program and q u e s t i o n s a s k i n g p e o p l e what t h e y w i l l pay l e a d to d i f f e r e n t a n s w e r s . The p r e s e n t s t u d y has a d o p t e d the l a t t e r s t r a t e g y as a method to t r y to q u a n t i f y how much p a t i e n t s v a l u e a t r e a t m e n t p r o g r a m . Thompson e t . a l . (1984) have e x p l o r e d t h i s i s s u e i n a r t h r i t i s p a t i e n t s and i d e n t i f i e d a number of c o n s t r a i n t s . F i r s t , a v e r y low r e s p o n s e r a t e (27%) a p p l i e d to the w i l l i n g n e s s - t o - p a y q u e s t i o n s posed to p a t i e n t s w i t h c h r o n i c a r t h r i t i s . The r e s e a r c h e r s s u s p e c t e d t h a t t h i s c o n c e p t may be a d i f f i c u l t one f o r p a t i e n t s to g r a s p . S e c o n d , Thompson e t . a l . (1984) c o u l d o f f e r o n l y t e n t a t i v e f i n d i n g s because of l i m i t e d s t a t i s t i c a l s i g n i f i c a n c e of the r e s u l t s of r e g r e s s i o n s . They c o n c l u d e d t h a t many p a t i e n t s w i t h l e s s s e v e r e a r t h r i t i s were more i n f l u e n c e d by a r t h r i t i c p a i n than by d i s a b i l i t y . The a r t h r i t i s s t u d y f o u n d t h a t the p a t i e n t r e s p o n s e s to the w i l l i n g n e s s - t o - p a y measure seemed to be a f f e c t e d by what seemed ' f a i r ' r a t h e r than by p e r s o n a l v a r i a b l e s such as income. In a d d i t i o n , problems w i t h f r a m i n g and i n t e r v i e w e r t e c h n i q u e i m p a i r e d the v a l i d i t y of the q u e s t i o n n a i r e . B e r w i c k and W e i n s t e i n (1985) r e p o r t e d t h a t p a t i e n t s were w i l l i n g to pay f o r d i a g n o s t i c i n f o r m a t i o n f o r i t s own s a k e , not j u s t f o r i t s r o l e i n m e d i c a l d e c i s i o n m a k i n g . S i x t y - t w o p a t i e n t s 3 O t h e r r e s e a r c h on t h e v a l u e of h e a l t h c a r e s e r v i c e s may be found i n A c t o n (1973, 1976) . 116 i n t h i s study were asked to v a l u e seven items of i n f o r m a t i o n about the s t a t u s of t h e i r h e a l t h and t h a t of t h e i r f e t u s . The m a j o r i t y of p a t i e n t s wished to know whether the baby was normal and whether t h e i r own h e a l t h was normal. They were a l s o w i l l i n g to pay, i n some c i r c u m s t a n c e s , to have i n f o r m a t i o n w i t h h e l d . For example, i n t h i s s tudy, n e a r l y 50% of women e l i g i b l e f o r u l t r a - sound d i a g n o s i s d u r i n g pregnancy wished to keep the gender of the baby a s u r p r i s e . Berwick and W e i n s t e i n found t h a t income l e v e l had a s i g n i f i c a n t e f f e c t on w i l l i n g n e s s - t o - p a y , w i t h f o u r very wealthy p a t i e n t s skewing the average w i l l i n g n e s s to pay from $430 per p a t i e n t to $709 per p a t i e n t . Tversky (1967) has e x p l o r e d t r a n s a c t i o n s s i m i l a r to w i l l i n g n e s s - t o - p a y b e h a v i o u r . In the T v e r sky study s u b j e c t s were asked to s t a t e a lowest s e l l i n g p r i c e f o r a gamble i n an e x p e r i - ment. S u b j e c t s were a l s o asked t h e i r maximum buying p r i c e f o r the gamble. The s e l l i n g p r i c e was u s u a l l y h i g h e r than the buying p r i c e . The p a t i e n t p r e f e r e n c e q u e s t i o n n a i r e i n the p r e s e n t study avoided the problems of monetary t r a d e - o f f s f o r h e a l t h s e r v i c e s by a s k i n g p a t i e n t s to t r a d e a per cent of a reasonable sum of money f o r one year of r e t i r e m e n t f o r an a l t e r e d w a i t i n g s t a t u s f o r h e a r t s u r g e r y . In t h i s way, i t was hoped t h a t the f a i r n e s s i s s u e would be r e s o l v e d and a l l p a t i e n t s c o u l d t r a d e a commodity of s i m i l a r r e l a t i v e v a l u e . Evans argued (1984) t h a t v a l u a t i o n s s h o u l d not be b i a s e d by i n d i v i d u a l wealth w h i l e they m a i n t a i n 117 an i n d i v i d u a l approach. T h e r e f o r e , i n the a n a l y s i s of r e s u l t s f o r t h i s q u e s t i o n , the p e r c e n t of the sum the p a t i e n t was w i l l i n g to pay was used. T h i s reduced the b i a s of l a r g e and s m a l l r e t i r e m e n t 'needs*. I n i t i a l l y , p a t i e n t s were o f f e r e d the o p p o r t u n i t y to "buy out" of a 5% chance of having a h e a r t a t t a c k over a 6 month p e r i o d . P a t i e n t s were asked how much they would be w i l l i n g to pay to get r i d of the 5% r i s k (gamble). P a t i e n t s were asked to pay f o r e l i m i n a t i n g the r i s k f o r 3 months, 5 months, and a l l but 1 day. The f o l l o w i n g t h r e e q u e s t i o n s e v a l u a t e d p a t i e n t w i l l i n g n - e s s - t o - p a y and compensation demanded f o r changing p o s i t i o n s on a h y p o t h e t i c a l w a i t i n g l i s t f o r treatment: To determine how many d o l l a r s you have f o r t h i s q u e s t i o n , s t a t e how much money you need f o r 1 year of r e t i r e m e n t , and make t h a t your annual income. Income = $ You are on a 6 month w a i t i n g l i s t f o r h e a r t s u r g e r y . I f o t h e r p o s i t i o n s on the l i s t were a v a i l a b l e , how much of your income f o r one year would you be w i l l i n g to exchange f o r the p o s i t i o n s l i s t e d below? I f you wait t h e r e i s a 5% chance you c o u l d have a h e a r t a t t a c k . To wait o n l y 3 months I would pay $ To wait o n l y 1 month I would pay $ To not wait at a l l I would pay $ 118 7.1. R e s u l t s of W i l l i n g n e s s to Pay T a b l e 3.8 summarizes the number of s u b j e c t s who were prepared to pay to reduce a 5% r i s k of a h e a r t a t t a c k . T a b l e 3.8. W i l l i n g n e s s to Pay f o r A l l P a t i e n t s and H e a l t h y S u b j e c t s , n=64 time frame: 3 mo. 5mo. a l l but 1 day number who would not pay: 20 13 8 number who would pay (% income) 44 (39.9%) 51 (46.1%) 56 (56.2%) 7.2. D i s c u s s i o n S u b j e c t s i n the p r e s e n t study were w i l l i n g to pay f o r r e d u c i n g the r i s k of a h e a r t a t t a c k when the r i s k c o u l d be e l i m i n a t e d sooner r a t h e r than l a t e r . More s u b j e c t s r e f u s e d to pay to reduce a r i s k they would bear f o r t h r e e months than r e f u s e d when the r i s k would l a s t o n l y u n t i l tomorrow. When p a t i e n t s were asked how they thought about t h i s r i s k , a t y p i c a l r e p l y was t h a t a 5% r i s k f o r one day would not l i k e l y a f f e c t them, w h i l e a 5% r i s k over a p e r i o d of months might a f f e c t them. T h i s thought p r o c e s s may be s i m i l a r to Tversky's (1974) 119 f i n d i n g t h a t s u b j e c t s tend to o v e r e s t i m a t e s m a l l p r o b a b i l i t i e s w h i l e u n d e r e s t i m a t i n g l a r g e ones. 7.3. C o n c l u s i o n s As w i t h p r e v i o u s s t u d i e s of w i l l i n g n e s s - t o - p a y , the p r e s e n t study produced no c o n c l u s i v e evidence t h a t t h i s t e c h n i q u e can measure the v a l u e of treatment (as a method of r e d u c i n g r i s k ) to a p a t i e n t . The data c e r t a i n l y i n d i c a t e d a t r e n d t h a t p a t i e n t s p r e f e r treatment sooner r a t h e r than l a t e r . However, between 12% and 30% of p a t i e n t s would not pay a n y t h i n g to take a treatment t h a t would reduce the r i s k of a h e a r t a t t a c k , e i t h e r because they d i d not f e e l the r i s k was s i g n i f i c a n t or they had l i t t l e c o n f i d e n c e i n the treatment. 8.0. The Endowment E f f e c t T h a l e r (1980) i n t r o d u c e d the term 'endowment e f f e c t ' to d e s c r i b e the r e l u c t a n c e of people to p a r t w i t h t h i n g s (or p o s i t i o n s ) they a l r e a d y p o s s e s s . The endowment e f f e c t appears to be s t r o n g when s u b j e c t s are asked to s t a t e s e l l i n g p r i c e s f o r goods or r i g h t s they a l r e a d y possess and buying p r i c e s f o r the same goods when they have not been owned b e f o r e . Knetsch, Kahneman and McNeil (1985) demonstrated t h i s e f f e c t i n a study of compensation demanded by r e n t e r s who were asked what compensation they would a c c e p t i n order to move to another apartment. For an 120 average r e n t of $443.00, r e n t e r s asked f o r compensations of $1,000.00 to $10,000.00. In the p a t i e n t p r e f e r e n c e study, h e a r t p a t i e n t s were asked t h e i r w i l l i n g n e s s to ' s e l l * top p o s i t i o n s on a h y p o t h e t i c a l w a i t i n g l i s t . The compensation demanded f o r a top p o s i t i o n was a proxy f o r the v a l u e of the p o s i t i o n t h a t had a l r e a d y been 'endowed*. I f the endowment e f f e c t was i n o p e r a t i o n , t h i s v a l u e would be l a r g e r than the p r i c e a p a t i e n t would be w i l l i n g to pay f o r a p o s i t i o n when the p a t i e n t was t o l d he was on the bottom of the l i s t . The q u e s t i o n s were as f o l l o w s : You are on a 6 month w a i t i n g l i s t f o r h e a r t s u r g e r y , and you a r e f i r s t on the l i s t . You have a l r e a d y waited 6 months. W a i t i n g l o n g e r has a 5% chance t h a t you c o u l d have a h e a r t a t t a c k . The same money i s a v a i l a b l e to everyone on the l i s t as i s a v a i l a b l e f o r you. No one i s s i c k e r than you. Would you g i v e up your p l a c e to wait 1 more week? How much compensation would you want? $ would you g i v e up your p l a c e to wait 3 more months? How much compensation would you want? $ Would you g i v e up your p l a c e to wait 6 more months? How much compensation would you want? $ 8.1. R e s u l t s of the Endowment E f f e c t Questions S u b j e c t s were expected to ask f o r more compensation to s e l l 121 what was viewed as a p o s i t i v e s t a t e than they were w i l l i n g to pay to a c q u i r e i t . They were a l s o expected to be r e l u c t a n t to r e l i n q u i s h a p o s i t i o n t h a t would expose them to the r i s k of a h e a r t a t t a c k . Very few s u b j e c t s were w i l l i n g to g i v e up f i r s t p l a c e on the w a i t i n g l i s t f o r any amount of money. Tabl e 3.9 i n d i c a t e s the compensation demanded by those who were w i l l i n g to g i v e up t h e i r p o s i t i o n . T a b l e 3.9. Compensation Demanded, n=64 g i v e up one week g i v e up t h r e e months g i v e up s i x months 53 s u b j e c t s (83%) would not s e l l or t r a d e t h e i r p o s i t i o n s . 11 s u b j e c t s would g i v e them up f o r 38% more income. 58 s u b j e c t s (91%) would not s e l l or t r a d e t h e i r p o s i t i o n s . 6 s u b j e c t s would g i v e them up f o r 57% more income. 60 s u b j e c t s (94%) would not s e l l or t r a d e t h e i r p o s i t i o n s . 4 s u b j e c t s would g i v e them up f o r 53% more income. notes: ( i ) Compensation i s l i s t e d as an a d d i t i o n a l per cent of a s t a t e d annual income. ( i i ) For s u b j e c t s who would not accept compensation, the r e s e a r c h e r confirmed with each s u b j e c t t h a t even 100% more income would not encourage the p a t i e n t to r e l e n q u i s h the p o s i t i o n on the w a i t i n g l i s t . Most s u b j e c t s s a i d they would not g i v e up t h e i r p o s i t i o n s f o r any amount of money. 122 When i t came to compensation demanded, the m a j o r i t y (53 out of 64, or 83%) of p a t i e n t s would not ac c e p t any sum of money to take on a 5% r i s k of a he a r t a t t a c k by g i v i n g up t h e i r top p o s i t i o n on the w a i t i n g l i s t . Those few who agreed to take compensation wanted much more money to accept a r i s k than they were w i l l i n g to pay to a v o i d i t once they had i t . For example, among p a t i e n t s w i t h m i l d a n g i n a , t h r e e were w i l l i n g to accept compensation from another p a t i e n t to ac c e p t a lower p o s i t i o n on the w a i t i n g l i s t . P a t i e n t #1, would pay n o t h i n g to get r i d of a 5% r i s k f o r 3 months, but he wanted an a d d i t i o n a l 6% of h i s annual income to take on the same r i s k . P a t i e n t #2 a l s o r e f u s e d to pay to get r i d of the 5% r i s k , w h i l e he wanted an a d d i t i o n a l 100% of h i s annual income to ac c e p t such a r i s k . S i m i l a r l y , p a t i e n t #3 was w i l l i n g to pay 12% of h i s income to a v o i d the r i s k , wanting i n r e t u r n an a d d i t i o n a l 75% of h i s income to take i t . A g a i n , the most n o t i c e a b l e d i f f e r e n c e between groups occured w i t h p a t i e n t s who had seve r e a n g i n a . T h i s group was the l e a s t w i l l i n g to pay to reduce r i s k , e s p e c i a l l y f o r 3 months. When these p a t i e n t s were asked why they d i d n ' t want to pay, a t y p i c a l response was: "I waited f o r 3 months f o r my bypass with a g r e a t e r r i s k of a he a r t a t t a c k than 5%. I don't t h i n k e l i m i n a t i n g t h a t r i s k (a 5% r i s k ) i s worth v e r y much." These p a t i e n t s may a l s o have had some n e g a t i v e f e e l i n g s towards h e a r t s u r g e r y , as noted i n Chapter 4. However, they were the l e a s t w i l l i n g to g i v e up a 123 p o s i t i o n on the w a i t i n g l i s t once they had i t . A c l e a r t r e n d was e s t a b l i s h e d a c r o s s a l l groups i n i n c r e a s e d w i l l i n g n e s s to pay as the r i s k r e d u c t i o n approaches c e r t a i n t y . I t i s i n t e r e s t i n g to note t h a t many p a t i e n t s were w i l l i n g to pay 100% of t h e i r income to have the r i s k e l i m i n a t e d tomorrow. The c o n s t r a i n t s of the q u e s t i o n prevented them from o f f e r i n g more than 100% f a l t h o u g h a number of p a t i e n t s s a i d they would pay a l l they c o u l d i n a d d i t i o n to the income a l l o w e d i n the q u e s t i o n . 8.2. C o n c l u s i o n s I t i s c l e a r from the data i n the p r e s e n t study t h a t p a t i e n t s as w e l l as h e a l t h y s u b j e c t s a t t r i b u t e g r e a t e r v a l u e to a p o s i t i o n they c u r r e n t l y h o l d than they are w i l l i n g to pay to a c q u i r e such a p o s i t i o n . S u b j e c t s ' c h o i c e s on q u e s t i o n s r e l a t i n g to w i l l i n g n e s s - t o - p a y and compensation demanded sho u l d be examined s i m u l t a n e o u s l y i f p a t i e n t p r e f e r e n c e s are to be f u l l y u n derstood. I f h e a l t h p r o f e s s i o n a l s are aware of the s t r e n g t h of the endowment e f f e c t , and i t s i n f l u e n c e on d e c i s i o n s , p a t i e n t s may be more e f f e c t i v e l y c o u n s e l l e d when a treatment chosen r e q u i r e s the p a t i e n t to wait or i f other c i r c u m s t a n c e s f o r c e the p a t i e n t to wait l o n g e r than expected. W a i t i n g l i s t s are a common source of p u b l i c f r u s t r a t i o n w i t h the h e a l t h system. F i n d i n g s from s t u d i e s such as t h i s one can i l l u m i n a t e the reasons why p u b l i c sentiment can be so s t r o n g . 124 9.0. Summary of F i n d i n g s T h i s chapter has p r e s e n t e d the r e s e a r c h f o u n d a t i o n s upon which the study q u e s t i o n s r e l a t i n g to e r r o r s of judgement were based. Data from s u b j e c t responses have s u p p l i e d evidence to support p r e v i o u s demonstrations of the c e r t a i n t y e f f e c t , p r e f e r e n c e r e v e r s a l , f r a m i n g , the s u b s t i t u t i o n e f f e c t , w i l l i n g n e s s - t o - p a y , and compensation demanded. Fewer s u b j e c t s i n the p r e s e n t study demonstrated asymmetric c h o i c e i n the domain of gains and l o s s e s than has been found i n oth e r s t u d i e s of t h i s judgement b i a s when money bets were used. The f o l l o w i n g chapter p r e s e n t s q u e s t i o n s e x p l o r i n g the i n f l u e n c e of independent v a r i a b l e s on s u b j e c t s ' c h o i c e s . The purpose of the a n a l y s i s of such v a r i a b l e s as p a t i e n t ' s age, degree of d i s a b i l i t y , and p r e v i o u s treatment h i s t o r y , was to determine whether the e r r o r s of judgement demonstrated i n t h i s c h a pter were compounded i n some groups of p a t i e n t s . C o o p e r a t i v e d e c i s i o n making by h e a l t h p r o f e s s i o n a l s and p a t i e n t s c o u l d be improved by a s e n s i t i v i t y toward p a t i e n t s most v u l n e r a b l e to e r r o r s of judgement. 125 CHAPTER 4 MEDICAL DECISION MAKING: P a t i e n t P r e f e r e n c e s , Demographic C h a r a c t e r i s t i c s , and Q u a l i t y of L i f e I s s u e s . 1.0 I n t r o d u c t i o n T h i s s t u d y of the p r e f e r e n c e s of p a t i e n t s w i t h h e a r t d i s e a s e has attempted to i l l u m i n a t e some of the i s s u e s c u r r e n t h e a l t h care p o l i c y i s a d d r e s s i n g by i d e n t i f y i n g p r e f e r e n c e p a t t e r n s f o r treatment among s p e c i f i c groups of p a t i e n t s . For example, c o n s i d e r a b l e a t t e n t i o n has been focused on the i n f l u e n c e t h a t the ageing of the p o p u l a t i o n w i l l have on h e a l t h care i n Canada (Evans, 1984). The debate has c e n t r e d around u t i l i z a t i o n p a t t e r n s and g r e a t e r needs f o r f u n d i n g due to the i n c r e a s i n g p r o p o r t i o n of e l d e r l y (over 65 years of age) i n the p o p u l a t i o n . Evans (1984, p.309) has s t a t e d t h a t i t i s not the a c t u a l ageing of the p o p u l a t i o n , i t i s t h a t "age-sex s p e c i f i c u t i l i z a t i o n r a t e s are themselves changing, i n such a way as to i n c r e a s e s u b s t a n t i a l l y the r e l a t i v e u t i l i z a t i o n of the e l d e r l y . " L i m i t e d a t t e n t i o n has been drawn to the a c t u a l p r e f e r e n c e s of o l d e r persons f o r p a r t i c u l a r types of care or f o r c e s s a t i o n of h e r o i c i n t e r v e n t i o n s . The approach of the study has been to l i n k independent v a r i a b l e s to the p a t i e n t s ' treatment c h o i c e s . The v a r i a b l e s s e l e c t e d were d i a g n o s i s , age, p r e v i o u s h e a l t h h i s t o r y , and h o s p i t a l e x p e r i e n c e . 126 The i n f l u e n c e of angina on p a t i e n t c h o i c e s was e x p l o r e d by a s k i n g p a t i e n t s to express t h e i r p r e f e r e n c e s f o r outcomes t h a t r e q u i r e d some p e r i o d of m o r b i d i t y , or asked the p a t i e n t to bear some r i s k of death d i r e c t l y a s s o c i a t e d w i t h treatment. The r e s u l t s of these q u e s t i o n s are p r e s e n t e d as the investment p a t i e n t s were w i l l i n g to make i n t h e i r own f u t u r e h e a l t h . Three time p e r i o d s were e x p l o r e d : one y e a r , f i v e y e a r s , and the l i f e y e ars expected by each p a t i e n t . F o l l o w i n g t h i s , the r i s k averseness of p a t i e n t s and h e a l t h y s u b j e c t s i s d i s p l a y e d i n g r a p h i c a l form and d i s c u s s e d . Data a r e a l s o p r e s e n t e d t h a t summarize p a t i e n t c h o i c e s when treatment c a r r i e d no r i s k of death. Two q u e s t i o n s guided the a n a l y s i s of the i n f l u e n c e of age on treatment c h o i c e s . F i r s t , d i d p a t i e n t s over age 65 have d i f f e r e n t p r e f e r e n c e s f o r treatment than younger p a t i e n t s ? And second, are these o l d e r p a t i e n t s more prone to e r r o r s of judgement i n d e c i s i o n making than younger p a t i e n t s ? F o l l o w i n g the a n a l y s i s of data r e g a r d i n g o l d e r p a t i e n t s i s a d i s c u s s i o n of t h r e e other independent v a r i a b l e s : the i n f l u e n c e of p r e v i o u s m y o c a r d i a l i n f a r c t i o n s on c h o i c e p a t t e r n s , the i n f l u e n c e of c o r o n a r y a r t e r y bypass g r a f t i n g on c h o i c e p a t t e r n s , and the i n f l u e n c e of angina on c h o i c e p a t t e r n s . 2.0 Investment i n Future H e a l t h A new emphasis on p r e v e n t i v e h e a l t h s t r a t e g i e s and l i f e s t y l e 127 m o d i f i c a t i o n motivated a number of q u e s t i o n s to e x p l o r e p a t i e n t s ' w i l l i n g n e s s to i n v e s t i n t h e i r f u t u r e h e a l t h . The stud y q u e s t i o n s asked how much s u b j e c t s were prepared to spend f o r f u t u r e consumption, where consumption was d e s c r i b e d as good h e a l t h without symptoms of coronary h e a r t d i s e a s e . The p a r t i c i - pants i n d i c a t e d the number of weeks they would be prepared to spend i n the h o s p i t a l now f o r p a i n r e l i e f l a t e r . Although some younger p a t i e n t s and h e a l t h y s u b j e c t s found i t d i f f i c u l t to r e l a t e to t h i s q u e s t i o n when a l i f e t i m e of good h e a l t h was o f f e r e d to them, o l d e r s u b j e c t s and p a t i e n t s w i t h l e s s than t en years of expected l i f e d i d not f i n d t h i s q u e s t i o n d i f f i c u l t to address. P a t i e n t s w i t h a r r y t h m i a or v a l v e d i s e a s e were o f f e r e d the same outcomes wi t h angina p a i n r e p l a c e d by 'your symptoms'. The f o l l o w i n g q u e s t i o n was used to determine p a t i e n t s ' w i l l i n g n e s s to i n v e s t i n f u t u r e h e a l t h : In each of these q u e s t i o n s you have to t r a d e weeks i n the h o s p i t a l now f o r e l i m i n a t i n g p a i n l a t e r . You w i l l have p a i n w h i l e i n the h o s p i t a l . To c o m p l e t e l y e l i m i n a t e angina p a i n : a) f o r 1 year, I would spend weeks i n the h o s p i t a l . b) f o r 5 y e a r s , I would spend weeks i n the h o s p i t a l . c) to e l i m i n a t e p a i n f o r the r e s t of my l i f e , I would spend weeks i n the h o s p i t a l . What would you be g i v i n g up to spend these weeks i n the h o s p i t a l ? 128 Table 4.1 summarizes the f i n d i n g s from each group, w i t h the stan d a r d d e v i a t i o n of each group i n c l u d e d to i n d i c a t e the range of i n vestments. The g r a p h i c r e p r e s e n t a t i o n i n F i g u r e 4.1, "Investment i n Fu t u r e H e a l t h " , i n d i c a t e s the importance o f r e l a t i n g the number of weeks each p a t i e n t group was w i l l i n g to spend to a c h i e v e time without symptoms, to the average l i f e expectancy of the group. The average l i f e expectancy f o r each d i a g n o s t i c group was c a l c u l a t e d u s i n g the p a t i e n t s ' s u b j e c t i v e statements of t h e i r l i f e expectancy. Ta b l e 4.1 Investment i n Fu t u r e H e a l t h by P a t i e n t Groups GROUP TIME PERIOD (number of weeks bid) p e r c e i ved 1 year 5 years l i f e l i f e expectancy ( i n years) h e a l t h y M 2.7 10.3 21.5 33.7 SD 2.0 11.8 24.4 13.2 Med. 3.0 8.0 10.0 35.0 ot h e r M 6.1 13.1 28.7 19.5 h e a r t SD 11.2 22.6 28.1 11.5 Med. 2.5 4.0 24.0 15.0 angina M 3.7 8.7 20.4 18.7 m i l d SD 5.9 13.3 25.6 8.8 Med. 2.0 4.0 12.0 20.0 angina M 6.6 13.9 31.1 13.1 severe SD 13.4 25.3 38.8 6.9 Med. 2.0 5.5 10.0 12.5 Notes: M=mean; SD=standard d e v i a t i o n ; Med.=median Figure 4 . 1 . 130 4.1 D i s c u s s i o n Healthy s u b j e c t s had the l e a s t w i l l i n g n e s s to i n v e s t i n f u t u r e h e a l t h when the investment was a h o s p i t a l s t a y . T h i s group b i d an average of 2.7 weeks i n the h o s p i t a l f o r one year of good h e a l t h . The p a t i e n t s w i t h m i l d angina b i d 3.7 weeks and those w i t h o t h e r forms of h e a r t d i s e a s e b i d 6.1 weeks i n the h o s p i t a l f o r a year of good h e a l t h . P a t i e n t s w i t h severe angina were prepared to i n v e s t the most: 6.6 weeks f o r one year of good h e a l t h . I t was a l s o i n t e r e s t i n g to note t h a t , even though the s e r i o u s l y i l l p a t i e n t s had l e s s than h a l f the l i f e expectancy of the h e a l t h y s u b j e c t s , they were prepared to i n v e s t o n e - t h i r d more time to ensure p a i n f r e e l i f e . These p a t i e n t s b i d an average of 31 weeks i n the h o s p i t a l f o r o n l y 13 years of expected l i f e w h i l e h e a l t h y s u b j e c t s b i d 21 weeks f o r 33 years of good h e a l t h . S e v e r a l p a t i e n t s i n the study groups s t a t e d t h a t they would be prepared to s t a y i n the h o s p i t a l as long as t h e i r d o c t o r s a i d they s h o u l d i n order to a c h i e v e a good h e a l t h outcome. These p a t i e n t s were encouraged to s t a t e a p r e f e r e n c e when the i n t e r v i e w e r asked i f 52 weeks would be an a c c e p t a b l e s t a y to a c h i e v e one year w i t h no angina p a i n . When p a t i e n t s r e a l i z e d t h a t they had an upper bound of t o l e r a n c e f o r a h o s p i t a l s t a y they were prepared to focus on a p e r s o n a l l y a c c e p t a b l e l e n g t h of time. 131 2.2. C o n c l u s i o n s The r e s u l t s i n these investment q u e s t i o n s supported the b e l i e f of the p h y s i c i a n s whose p a t i e n t s p a r t i c i p a t e d i n the study. These p h y s i c i a n s s t a t e d t h a t p a t i e n t s were the most w i l l i n g to a l t e r l i f e s t y l e b e haviours such as smoking when they had r e c e n t l y e x p e r i e n c e d a h e a r t a t t a c k or sev e r e anagina p a i n . In o t h e r words, a p a t i e n t seemed most w i l l i n g to i n v e s t i n f u t u r e h e a l t h at a time when he/she was most i l l . T h i s f i n d i n g h e l p s to e x p l a i n the momentum of the ' c u r a t i v e ' r a t h e r than ' p r e v e n t i v e ' approach of m e d i c a l care most p r e v a l e n t i n some p h y s i c i a n behaviour as noted i n Chapter 1. I t a l s o e x p l a i n s why h e a l t h e d u c a t i o n and h e a l t h promotion may o f t e n appear to f a l l on deaf e a r s . 3.0 Value of R i s k Avoidance The r i s k avoidance q u e s t i o n s t e s t e d whether p a t i e n t s w i t h d i f f e r e n t degrees of d i s a b i l i t y demonstrated d i f f e r e n t amounts of a v e r s i o n to the r i s k a s s o c i a t e d with treatment. In the case of p a t i e n t s w i t h coronary h e a r t d i s e a s e , the r e l a t i v e d e s i r a b i l i t y of p a i n r e l i e f accompanied by treatment r i s k compared to c o n t i n u i n g p a i n w i t h no r i s k formed the t r a d e - o f f s used to develop a u t i l i t y f u n c t i o n . 1 1 A comprehensive d i s c u s s i o n of u t i l i t i e s may be found i n Arrow (1958, 1963, 1965, 1967, 1971) 132 Chapter 2 i n c l u d e d a review of the method of McNeil e t . a l . (1978) of u s i n g c e r t a i n t y e q u i v a l e n t s as p o i n t s on a u t i l i t y s c a l e to d e s c r i b e r i s k a v e r s i o n f o r cancer p a t i e n t s . E a r l i e r , Pauker (1976) developed u t i l i t y f u n c t i o n s by a n a l y s i s of two dimensions of p r e f e r e n c e : q u a n t i t y of l i f e and q u a l i t y of l i f e . Q u a l i t y was "determined by the presence or absence of d i s a b l i n g angina and by the p a i n and s u f f e r i n g n e c e s s i t a t e d by c o r o n a r y bypass s u r g e r y " (Pauker, 1976, p . 8 ) . In a subsequent study, M c N e i l , Weschelbaum and Pauker (1981) demonstrated t h a t a u t i l t i y f u n c t i o n i n c o r p o r a t i n g q u a l i t y of l i f e was d i s p l a c e d downward from one u s i n g o n l y l e n g t h of l i f e . S u b j e c t s i n t h i s s t u d y were asked to g i v e p r e f e r e n c e s f o r s u r g e r y or r a d i a t i o n f o r l a r y n g e a l c a n c e r . Surgery o f f e r e d a l o n g e r l i f e expectancy at the expense of the a b i l i t y to speak w h i l e r a d i a t i o n o f f e r e d s h o r t e r s u r v i v a l with the a b i l i t y to speak i n t a c t . The q u e s t i o n s used i n d e t e r m i n i n g p a t i e n t s ' u t i l i t y f o r r i s k avoidance were developed from the t h r e e s t u d i e s d e s c r i b e d above. They were as f o l l o w s : For t h i s q u e s t i o n use the number of years you expect to l i v e as the years f r e e of angina p a i n . S t a t e how many years of l i f e you would take (with angina l i k e you have now) i n order to be i n d i f f e r e n t between the years with angina and the f o l l o w i n g gambles. Would you agree to take a p i l l t h a t o f f e r e d a 98% chance of complete r e c o v e r y from your h e a r t d i s e a s e and a 2% r i s k of death? yes no 133 Would you agree to exchange a l l the years you expect to l i v e w i t h h e a r t d i s e a s e f o r one year of p e r f e c t h e a l t h ? yes no C h o i c e #1: T h i s treatment i s a p i l l t h a t has a 50% chance of c o m p l e t e l y e l i m i n a t i n g angina p a i n f o r your l i f e t i m e and a 50% chance of immediate death. Take the p i l l ? yes no Take years of l i f e f o r s u r e . Choice #2: T h i s treatment i s a p i l l t h a t has a 75% chance of c o m p l e t e l y e l i m i n a t i n g angina p a i n f o r your l i f e t i m e and a 25% chance of immediate death. Take the p i l l ? yes no Take years of l i f e f o r s u r e . Choice #3: T h i s treatment i s a p i l l t h a t has a 25% chance of c o m p l e t e l y e l i m i n a t i n g angina p a i n f o r your l i f e t i m e and a 75% chance of immediate death. Take the p i l l ? yes no Take years of l i f e f o r s u r e . T h i s q u e s t i o n was a d m i n i s t e r e d w i t h the a s s i s t a n c e of f o u r d i f f e r e n t l y c o l o u r e d , empty p i l l c a p s u l e s , each r e p r e s e n t i n g a 25% chance of treatment f a i l u r e . I n d i f f e r e n c e was e x p l a i n e d to s u b j e c t , and f o r each answer o f f e r e d by a s u b j e c t , the r e s e a r c h e r asked whether the years f o r sure were e q u i v a l e n t to the gamble. In other words, would the s u b j e c t be prepared to take e i t h e r o f f e r ? Was he/she i n d i f f e r e n t between the two? T h i s technique helped s u b j e c t s d e a l w i t h i n d i f f e r e n c e and the changing p r o b a b i l i t i e s of outcomes. 134 P a t i e n t s who were r i s k a v e r s e were expected to take a s h o r t e r l i f e w i t h c e r t a i n t y than a lon g e r l i f e accompanied by a r i s k of death. As the p r o b a b i l i t y of s u r v i v a l decreased from 75% to 50% to 25%, r i s k a v e r s i o n was expected to i n c r e a s e more than p r o p o r t i o n a l l y . T h i s e x p e c t a t i o n was based on the r e s u l t s of McNeil e t . a l . (1978) who found t h a t cancer p a t i e n t s demonstrated a v e r s i o n to the r i s k of e a r l y death due to s u r g e r y . 3.1. R e s u l t s and D i s c u s s i o n In T a b l e 4.2 the r e s u l t s f o r each group a re l i s t e d a l o n g w i t h the average p e r c e i v e d l i f e expectancy of the group. TABLE 4.2. GROUP Value of A v o i d i n g L i f e R i s k PER CENT CHANCE OF SURVIVAL (years accepted w i t h c e r t a i n t y ) p e r c e i v e d 25% 50% 75% l i f e h e a l t h y M 2.9 10.9 18.3 33.7 SD 2.5 5.7 10.7 13.2 o t h e r M 4.4 8.3 14.0 19.5 h e a r t SD 4.5 6.1 10.7 11.6 angi na M 4.1 7.9 13.4 18.7 m i l d SD 2.3 3.4 6.8 8.8 angina M 2.4 6.6 9.4 13.1 s e v e r e SD 1.9 3.9 4.5 6.0 i n years) Notes: M=mean; SD=standard d e v i a t i o n . 135 A comparison of the responses of each d i a g n o s t i c group i s prese n t e d i n F i g u r e 4.2. T h i s f i g u r e dedmonstrates the r e l a t i v e l y r i s k a v e r s e p r e f e r e n c e s of h e a l t h y s u b j e c t s and the more r i s k s e e k i n g p r e f e r e n c e s of p a t i e n t s w i t h h e a r t d i s e a s e . F i g u r e s 4.3 to 4.6 i l l u s t r a t e the b i d s made by each d i a g n o s t i c group. A r i s k a v e r s e i n d i v i d u a l p r e f e r s a c e r t a i n s u r v i v a l of Y years to any gamble f o r s u r v i v a l w i t h e x p e c t a t i o n Y. I f a s u b j e c t demonstrated r i s k n e u t r a l i t y , h i s / h e r b i d s would f a l l on the d i a g o n a l l i n e j o i n i n g the o r i g i n of the graph wi t h the upper r i g h t hand c o r n e r . Healthy s u b j e c t s ( F i g u r e 4.3) demonstrated the s t r o n g e s t r i s k a v e r s i o n as i s shown by the steepness of the curve as i t d e p a r t s from the o r i g i n . P a t i e n t s w i t h m i l d angina ( F i g u r e 4.4) and oth e r forms of h e a r t d i s e a s e ( F i g u r e 4.5) were l e s s r i s k a v e r s e , w h i l e those w i t h s e v e r e angina ( F i g u r e 4.6) were almost r i s k n e u t r a l . These s u b j e c t s were almost i n d i f f e r e n t between the gamble o f f e r e d i n the q u e s t i o n and c e r t a i n s u r v i v a l . The c o n t r i b u t i o n made by t h i s a d a p t a t i o n of the McNeil e t . a l . (1978) study i s the e x t e n s i o n of p r e v i o u s understanding of p a t i e n t p r e f e r e n c e s by i n d i c a t i n g t h a t p a t i e n t s can respond to p r e f e r e n c e q u e s t i o n s with t h e i r own l i f e expectancy as the anchor p o i n t , r a t h e r than a d e r i v e d s t a n d a r d l i f e expectancy s e t by the r e s e a r c h e r . Data generated by t h i s q u e s t i o n a l s o i n d i c a t e d t h a t h i g h l e v e l s of p a i n and d i s a b i l i t y reduced r i s k avoidance i n p a t i e n t s w i t h coronary h e a r t d i s e a s e . Figure 4.2. RISK AVERSION IN HEART STUDY GROUPS 120-1 20 H • i 1 , r 0 5 10 15 20 25 30 35 YEARS OF LIFE ACCEPTED FOR SURE Figure 4.3. UTILITY OF RISK AVERSION IN HEALTHY SUBJECTS 120 - i YEARS OF LIFE ACCEPTED FOR SURE Figure 4.4. UTILITY OF RISK AVERSION IN HEART DISEASE CONTROL PATIENTS > or ZD GO O >- CD < CD o cr: C L 120 n 100 H 5 .. 10 15 YEARS OF LIFE ACCEPTED FOR SURE Figure 4 . 5 . UTILITY OF RISK AVERSION FOR PATIENTS WITH MILD ANGINA 120 - i YEARS OF LIFE ACCEPTED FOR SURE UTILITY OF RISK AVERSION IN PATIENTS WITH SEVERE ANGINA 120 -i Y E A R S OF LIFE ACCEPTED FOR SURE 141 There are a number of p l a u s i b l e reasons why t h i s s e t of p r e f e r e n c e s was e l i c i t e d . F i r s t , p a t i e n t s may not have under- stood the q u e s t i o n or been i m p l i c i t l y encouraged by the i n t e r v i e w e r to s t a t e a number of years h i g h e r or lower than the minimum number of years they would accept i n r e t u r n f o r a v o i d i n g the r i s k . Second, some p a t i e n t s may have p r e f e r r e d the r i s k y c h o i c e . S i n c e p a t i e n t s and s u b j e c t s were i n t e r v i e w e d i n the order i n which they agreed to p a r t i c i p a t e r a t h e r than by d i a g n o s t i c group, the f i r s t a l t e r n a t i v e would a p p l y to a l l p a t i e n t s thus b i a s i n g a l l groups e q u a l l y . The second reason, r i s k p r e f e r e n c e , remains a p o s s i b i l i t y . When each p a t i e n t ' s responses were e v a l u a t e d , more p a t i e n t s i n the h e a r t d i s e a s e c o n t r o l group (shown as 'other h e a r t ' i n the f i g u r e s ) e l e c t e d to take the r i s k ( i d e n t i f i e d by the ' p i l l ' ) than i n any o t h e r group. F i v e of n i n e t e e n (26.3%) p r e f e r r e d the p i l l . These p a t i e n t s were s a y i n g , i n e f f e c t , t h a t they would p r e f e r a 75% chance of complete r e c o v e r y and a 25% chance of death over a known l i f e expectancy w i t h h e a r t d i s e a s e . Among 15 h e a l t h y s u b j e c t s , none asked f o r the p i l l , two out of 15 p a t i e n t s w i t h m i l d angina wanted the p i l l , w h i l e t h r e e of 14 p a t i e n t s w i t h s e v e r e angina p r e f e r r e d the p i l l . I t appeared t h a t p a t i e n t s w i t h more sev e r e i l l n e s s were prepared to a c c e p t g r e a t e r r i s k f o r the a l l e v i a t i o n of symptoms. T h i s behaviour was r e a s o n a b l e , 142 c o n s i d e r i n g the e f f e c t of s e v e r e angina on a p a t i e n t ' s a b i l i t y to l i v e a normal l i f e . 3.2. A n a l y s i s of U t i l i t y Curves f o r Risk A v e r s i o n The u t i l i t y curves i n F i g u r e s 4.3 to 4.3 were a n a l y s e d u s i n g the T r a p e z o i d a l Rule i n order to determine whether a r e a l d i f f e r e n c e e x i s t e d between the d i a g n o s t i c groups. T h i s Rule i s a method f o r d e t e r m i n i n g the area under a c u r v e . For the purposes of t h i s a n a l y s i s , the r e s u l t s of the c a l c u l a t i o n s have been termed "the r i s k a v e r s i o n s c o r e " . The l a r g e r the value of t h i s s c o r e , the lower was the w i l l i n g n e s s of the p a t i e n t or s u b j e c t group to accept a treatment r i s k . I f the s c o r e was z e r o , or c l o s e to z e r o , the group was i d e n t i f i e d as r i s k n e u t r a l w h i l e a n e g a t i v e s c o r e would imply r i s k s e e k i n g . In the p r e s e n t study a r i s k n e u t r a l p a t i e n t was prepared to a c c e p t whatever r i s k a p p l i e d to a treatment t h a t would reduce the p a i n and d i s a b i l i t y a s s o c i a t e d with c o r o n a r y a r t e r y d i s e a s e . T a b l e 4.3. Risk A v e r s i o n Scores of D i a g n o s t i c Groups GROUP SCORE h e a l t h y 498. 75 h e a r t d i s e a s e c o n t r o l s 63. 75 m i l d angina 66. 25 severe angina 31. 35 143 The s c o r e s i n Table 4.3 r e f l e c t the s l o p e of each u t i l i t y c urve as w e l l as the w e i g h t i n g c o n t r i b u t e d by the average l i f e expectancy as p e r c e i v e d by the members of each d i a g n o s t i c group. The h i g h s c o r e of the h e a l t h y s u b j e c t s i n d i c a t e s a g r e a t e r a v e r s i o n to treatment r i s k than was demonstrated by p a t i e n t s w i t h s e v e r e a n g i n a . P a t i e n t s w i t h m i l d angina and h e a r t d i s e a s e c o n t r o l s demonstrated an i n t e r m e d i a t e l e v e l of a v e r s i o n . The c l i n i c a l i m p l i c a t i o n s of a u t i l i t y measure to determine which p a t i e n t s should r e c e i v e r a d i a t i o n f o r lung cancer have been d e s c r i b e d by McNeil e t . a l . (1978). The c o n t r i b u t i o n of a " r i s k a v e r s i o n s c o r e " i s t h a t i t a l l o w s a p a t i e n t ' s a t t i t u d e s toward treatment r i s k and the p a t i e n t ' s l i f e expectancy to be combined i n t o one s c o r e t h a t c o u l d be used t o i d e n t i f y those p a t i e n t s most w i l l i n g to take a treatment whose outcome was u n c e r t a i n . The r i s k a v e r s i o n s c o r e d e s c r i b e d above i s not an orthodox method of d e s c r i b i n g expected u t i l i t y . B e f o r e i t may be c o n s i d e r e d as a u s e f u l measure i t sh o u l d be compared to ot h e r more e s t a b l i s h e d t e c h n i q u e s . T h i s comparison was not made i n the p r e s e n t study. 4.0. P r e f e r e n c e s f o r M o r b i d i t y with no Risk In two q u e s t i o n s p a t i e n t s were asked to i n d i c a t e p r e f e r r e d treatments when the p r o b a b i l i t y of su c c e s s v a r i e d but t h e r e were no l i f e r i s k s a t t a c h e d to the treatment. As was d i s c u s s e d i n the 144 s e c t i o n on 'framing' i n the p r e v i o u s c h a p t e r , the i n f l u e n c e e x e r t e d by framin g i s powerful enough to impair the a b i l i t y of the q u e s t i o n to a c c u r a t e l y determine a d i f f e r e n c e between p a t i e n t groups i n w i l l i n g n e s s to t o l e r a t e m o r b i d i t y w i t h no r i s k . The q u e s t i o n was as f o l l o w s : Would you agree to 2 months of mandatory bed r e s t at home i f your chances of c o m p l e t e l y e l i m i n a t i n g angina p a i n f o r 2 years were: (answer yes or no) yes/no 90% 70% 50% 30% 10% 1% I f you have not accepted any of the chances above, why would you not a c c e p t bed r e s t ? 4.1. R e s u l t s and D i s c u s s i o n T h i s q u e s t i o n d i d not s i g n i f i c a n t l y d i f f e r e n t i a t e between the p a t i e n t and h e a l t h y s u b j e c t groups. I t i s p o s s i b l e to r e p o r t o n l y t h a t a t r e n d appeared i n the group of p a t i e n t s w i t h severe a n g i n a . These p a t i e n t s were l e s s w i l l i n g to accept treatments with a p r o b a b i l i t y of success below 50% than were other p a t i e n t groups. Of those w i l l i n g to take treatments a t home, the average a c c e p t a b l e p r o b a b i l i t i e s of success were as f o l l o w s : h e a l t h y 145 s u b j e c t s , 53%; h e a r t c o n t r o l p a t i e n t s , 51%; p a t i e n t s w i t h m i l d a n gina, 44%, and p a t i e n t s with s e v e r e a n g i n a , 70%. These data suggest t h a t s e r i o u s l y i l l p a t i e n t s want to take treatments w i t h a h i g h e r p r o b a b i l i t y of s u c c e s s , even i f the treatment i s n o n - i n v a s i v e (such as bed r e s t a t home), than do l e s s i l l or h e a l t h y s u b j e c t s . Not a l l p a t i e n t s were w i l l i n g to a c c e p t bed r e s t : one of 15 h e a l t h y s u b j e c t s r e f u s e d , f o u r of 20 h e a r t c o n t r o l p a t i e n t s r e f u s e d , f o u r of 15 p a t i e n t s w i t h m i l d angina r e f u s e d , and one of 14 p a t i e n t s w i t h s e v e r e angina r e f u s e d . An e v a l u a t i o n of comments p r o v i d e d by respondents i n d i c a t e d t h a t a number of f a c t o r s o t h e r than d i s a b i l i t y l e v e l were s i g n i f i c a n t c o n t r i b u t o r s to w i l l i n g n e s s to take treatments a t home f o r two months. These i n c l u d e d the a v a i l a b i l i t y of a c a r e g i v e r , demands of a job or f a m i l y , l e v e l of r e s t l e s s n e s s , w i l l i n g n e s s to do 'whatever the d o c t o r wants', and l i m i t e d l i f e expectancy (the p a t i e n t d i d not want to waste what l i t t l e l i f e he had l e f t r e s t i n g i n bed). The f o l l o w i n g s e c t i o n s e x p l o r e the r e s u l t s of the q u e s t i o n s a n a l y s e d by the age of the p a t i e n t and the p r e v i o u s h e a l t h h i s t o r y of the p a t i e n t . 5.0 P a t i e n t Age as an Independent V a r i a b l e Data from p a t i e n t and s u b j e c t h i s t o r i e s were an a l y s e d to determine whether s e v e r i t y of d i s e a s e was l i n k e d to p a t i e n t age. P a t i e n t age was not found to be a p r e d i c t o r of s e v e r i t y of 146 coronary or o t h e r heart d i s e a s e i n the study groups. The average age of p a t i e n t s w i t h v a l v e d i s e a s e or a r r y t h m i a s was 56.4 y e a r s , w h i l e the average age of groups w i t h m i l d and severe angina was 59.1 y e a r s . The range of ages was a l s o s i m i l a r among groups. Re- c a l l t h a t Chapter 2 r e p o r t e d a study of c o r o n a r y a r t e r y bypass g r a f t i n g a t the Ottawa Heart I n s t i t u t e where the average p a t i e n t age was 55.3 years w i t h a range of 39 to 73 y e a r s , very s i m i l a r to the p a t i e n t groups i n the p r e s e n t study. 5.1. V u l n e r a b i l i t y to the I n f l u e n c e of the Framing B i a s T h i s study has shown t h a t framing e x e r t s a powerful i n f l u e n c e over p a t i e n t p r e f e r e n c e s as expressed by w i l l i n g n e s s to p a r t i c i p a t e i n a treatment w i t h a l e s s than c e r t a i n outcome. When the p a t i e n t responses were c l a s s i f i e d by age, the 23 p a t i e n t s who e x h i b i t e d a v u l n e r a b i l i t y to framing were found to have an average age of 56.7. Of the 24 p a t i e n t s who demonstrated a c o n s i s t e n t c h o i c e , the average age was found to be 54.7. The d i f f e r e n c e i n average age was not s t a t i s t i c a l l y s i g n i f i c a n t , but i t must be noted t h a t the study groups were s m a l l . These data suggest t h a t framing has a u n i v e r s a l i n f l u e n c e , and t h a t as many as o n e - t h i r d to o n e - h a l f of p a t i e n t s w i l l change t h e i r c h o i c e due to the d e s c r i p t i o n of the treatment outcome. 6.0. P r e v i o u s H e a l t h E x p e r i e n c e as an Independent V a r i a b l e The f e a r , u n c e r t a i n t y , and p a i n a s s o c i a t e d w i t h a m y o c a r d i a l 147 i n f a r c t i o n are f e e l i n g s t h a t p a t i e n t s i n the study c o u l d d e s c r i b e c l e a r l y , even i f the e x p e r i e n c e had o c c u r r e d many years b e f o r e . S i n c e Zook and Moore's (1977) d e s c r i p t i o n of the h i g h c o s t users of h e a l t h care suggested t h a t p a t i e n t s w i t h h e a r t d i s e a s e were f r e q u e n t l y h o s p i t a l i z e d , the study sought to determine whether p r e v i o u s h i s t o r y of a h e a r t a t t a c k and subsequent h o s p i t a l i z a t i o n had an i n f l u e n c e on a p a t i e n t ' s a t t i t u d e toward f u t u r e h o s p i t a l i z a t i o n . The r e s e a r c h q u e s t i o n asked was: Would p a s t e x p e r i e n c e b i a s c u r r e n t a t t i t u d e s towards h o s p i t a l i z a t i o n ? P a t i e n t s were asked t o : Choose between the f o l l o w i n g h o s p i t a l s o f f e r i n g treatment. Assume t h a t the treatment has s i d e e f f e c t s t h a t prevent t r y i n g another f o r a t l e a s t two y e a r s . While you wait you bear a 5% r i s k of having a h e a r t a t t a c k . H o s p i t a l A: W a i t i n g time i s 6 months ( a l l p a t i e n t s have angina f o r 6 months), a f t e r the treatment a l l p a t i e n t s are f r e e of angina f o r 4 y e a r s . H o s p i t a l B: No w a i t i n g time, a f t e r the treatment p a t i e n t s a r e f r e e of angina f o r 3 y e a r s . A: wait 6 months B: no wait I f you chose h o s p i t a l A, how l o n g would angina p a i n have to be e l i m i n a t e d at h o s p i t a l B to get you to choose h o s p i t a l B? I f you chose h o s p i t a l B, how long would angina p a i n have to be e l i m i n a t e d at h o s p i t a l A to get you to choose h o s p i t a l A? 148 6.1. R e s u l t s and D i s c u s s i o n Of the 64 s u b j e c t s i n t e r v i e w e d , 21 had s u f f e r e d a m y o c a r d i a l i n f a r c t i o n and 43 had not. Tab l e 4.6 summarizes the w a i t i n g c h o i c e s of these s u b j e c t s . TABLE 4.4. M y o c a r d i a l I n f a r c t i o n and W a i t i n g Choices wait no wait t o t a l h e a r t a t t a c k 10 (47 .6%) 11 (52 .4%) 21 no h e a r t a t t a c k 16 (37 .2%) 27 (62 .8%) 43 t o t a l 26 38 64 Notes: p=0.42 Table 4.4 shows t h a t a g r e a t e r p r o p o r t i o n of p a t i e n t s who have had a h e a r t a t t a c k are w i l l i n g to wait s i x months f o r treatment than those, i n c l u d i n g h e a l t h y s u b j e c t s , who have not (48% versus 37%) , alth o u g h t h i s d i f f e r e n c e was not s i g n i f i c a n t . T h i s q u e s t i o n of w i l l i n g n e s s to wait has c o n s i d e r a b l e s i g n i f i - cance i n the h o s p i t a l - system because of the p o s s i b i l i t y of long w a i t s f o r d i a g n o s t i c procedures and s u r g e r y f o r p a t i e n t s who s u r v i v e a h e a r t a t t a c k . H e a l t h a d m i n i s t r a t o r s may be a b l e to o f f e r a more s e n s i t i v e approach to p a t i e n t s r e q u i r e d to wait i f some ex ante d e t e r m i n a t i o n c o u l d be used to d i f f e r e n t i a t e those w i l l i n g to wait from those whose a n x i e t y was i n c r e a s e d by w a i t i n g . 149 7.0. The I n f l u e n c e of a Coronary A r t e r y Bypass on Choices The w a i t i n g q u e s t i o n s were a l s o a n a l y s e d by bypass h i s t o r y to determine i f p r e v i o u s e x p e r i e n c e w i t h s u r g i c a l i n t e r v e n t i o n a l t e r e d w i l l i n g n e s s to wait f o r t r e a t m e n t . In the study group o v e r a l l , 26 s u b j e c t s p r e f e r r e d to wait w h i l e 38 d i d not want to wait f o r h o s p i t a l c a r e . T a b l e 4.5 summarizes the p r e f e r e n c e s of these s u b j e c t s when bypass e x p e r i e n c e i s c o n s i d e r e d an indepen- dent v a r i a b l e . wait no wait t o t a l bypass 7 (58.3%) 5 (41.7%) 12 no bypass 19 (36.5%) 33 (63.5%) 52 t o t a l 26 38 64 Notes: F i s h e r ' s p=.14 The appearance of a n o t i c e a b l e , but not s i g n i f i c a n t d i f f e r - ence between the p r o p o r t i o n of bypass p a t i e n t s w i l l i n g to wait s i x months f o r h o s p i t a l c a r e , compared to the p r o p o r t i o n w i l l i n g to wait who d i d not have a bypass, suggested t h a t an e x p e r i e n c e with s u r g i c a l treatment i n c r e a s e d the t o l e r a n c e f o r w a i t i n g . When these p a t i e n t s were asked to d e s c r i b e why they were w i l l i n g 150 were w i l l i n g to w a i t , the common r e p l i e s were: "I had to wait n e a r l y s i x months f o r my bypass w i t h a r i s k of having another h e a r t a t t a c k always p r e s e n t ; s i x months i s n ' t a bad w a i t . " and, "I found having a bypass a r e a l l y unpleasant e x p e r i e n c e , I don't want another too soon." One c o n c l u s i o n t h a t c o u l d be t e n t a t i v e l y drawn from these f i n d i n g s i s t h a t people w i t h l i t t l e exposure to i n t e n s i v e h o s p i t a l c a r e are more anxious to have c a r e immediately a v a i l a b l e than people who have been i n the system b e f o r e . In terms of p o l i c y c o n s i d e r a t i o n s , one c o u l d suggest t h a t the a v a i l a b i l i t y problems i d e n t i f i e d by non-users may be exaggerated when compared to a v a i l a b i l i t y c o n s t r a i n t s i d e n t i f i e d by those who have used h o s p i t a l s . 8.0. H e a l t h E x p e r i e n c e and R i s k Avoidance How does a p e r s o n a l e x p e r i e n c e w i t h e i t h e r a m y o c a r d i a l i n f a r c t i o n or a coronary bypass i n f l u e n c e a p a t i e n t ' s c h o i c e of a treatment t h a t c a r r i e s a r i s k of death? I t appears t h a t exposure to r i s k of death i n the p a s t i n c r e a s e s a person's a b i l i t y to a c c e p t r i s k i n the f u t u r e . The q u e s t i o n used has been d e s c r i b e d i n Chapter 3 i n the d i s c u s s i o n of the c e r t a i n t y e f f e c t . The f i r s t o p t i o n d e s c r i b e d i n Table 4.6 i s a treatment t h a t o f f e r e d 5 years of p a i n r e l i e f w i t h no r i s k of death. The second o p t i o n o f f e r e d 6 years of p a i n r e l i e f accompanied by a 10% r i s k of death. The 151 expected v a l u e of the second treatment o p t i o n was 0.4 years l o n g e r than the f i r s t o p t i o n . 8.1. R e s u l t s and D i s c u s s i o n T a b l e 4.6 summarizes the f i n d i n g s a c r o s s f i v e c l a s s i f i - c a t i o n s of s u b j e c t s by p r e v i o u s h e a l t h e x p e r i e n c e . TABLE 4.6. H e a l t h E x p e r i e n c e and R i s k Avoidance p a s t c h o i c e h i s t o r y take 5 f o r sure take 6 with r i s k t o t a l no MI & no bypass 39 (92.9%) 3 (7.1%) 42 have had MI 16 (76.2%) 5 (23.8%) 21 have had bypass 10 (76.9%) 3 (23.1%) 13 both MI & bypass 6 (66.6%) 3 (33.3%) 9 a l l s u b j e c t s 58 (90.6%) 8 (9.4%) 64 notes: (a) MI = m y o c a r d i a l i n f a r c t i o n (b) In the Mantel t e s t f o r t r e n d d i f f e r e n c e s , p=.027 What became apparent from the r e s u l t s of the Mantel t e s t f o r a s i g n i f i c a n t t r e n d i n the r e s u l t s of Ta b l e 4.6, was that as p a t i e n t s were exposed to the s t r e s s of m y o c a r d i a l i n f a r c t i o n and 152 bypass s u r g e r y , t h e i r w i l l i n g n e s s to assume r i s k i n c r e a s e d . The p r o p o r t i o n of p a t i e n t s w i l l i n g to opt f o r the treatment with a 10% r i s k of death i s t h r e e times l a r g e r f o r p a t i e n t s w i t h p a s t e x p e r i e n c e w i t h a m y o c a r d i a l i n f a r c t i o n or bypass (23%) than f o r those without (7%) . I t i s of i n t e r e s t to note t h a t a l t h o u g h the expected v a l u e i s hig h e r f o r the o p t i o n of s i x years w i t h no p a i n accompanied by a 10% r i s k of death than i t i s f o r the f i v e year o p t i o n w i t h c e r t a i n t y , the v a s t m a j o r i t y (90.6%) of s u b j e c t s were not i n f l u e n c e d by the h i g h e r expected v a l u e of 5.4 y e a r s . An a n a l y s i s was a l s o conducted to compare a p a t i e n t ' s e x p e r i e n c e w i t h angina p a i n as an independent v a r i a b l e a c t i n g as a p r e d i c t o r of treatment c h o i c e when a treatment c a r r i e d a r i s k of death of 10%. P a t i e n t s w i t h p r e v i o u s angina who were c l a s s i f i e d as h e a r t d i s e a s e c o n t r o l p a t i e n t s were i n c l u d e d i n t h i s a n a l y s i s , a l o n g w i t h p a t i e n t s w i t h c u r r e n t angina. In T a b l e 4.7, the r i s k y c h o i c e i s summarized by l e v e l of angina p a i n , showing t h a t angina i n c r e a s e s w i l l i n g n e s s to bear r i s k f o r a h i g h e r expected g a i n , but the i n c r e a s e i s o n l y 10%. T h i s d i f f e r e n c e was not s i g n i f i c a n t . 153 TABLE 4.7. Angina P a i n and R i s k y Choice 6 years with r i s k 5 years f o r sure t o t a l angina 4 (21.1%) 15 (78.9%) 19 no angina 4 (11.4%) 31 (88.6%) 35 t o t a l 8 46 54 Notes: There was no s i g n i f i c a n t d i f f e r e n c e between groups. 9.0. H e a l t h E x p e r i e n c e and Choice of S u r g i c a l Treatment Study s u b j e c t s were g i v e n a q u e s t i o n t h a t d i d not use the words " s u r g e r y " or "drug therapy", but the outcomes d e s c r i b e d i n the q u e s t i o n matched the p r o b a b i l i t i e s of treatment outcomes o f f e r e d by these two methods as d e s c r i b e d i n Chapter 1. The r e s e a r c h q u e s t i o n asked: would p a t i e n t s who had a l r e a d y been t r e a t e d s u r g i c a l l y p r e f e r the treatment whose outcome p r o b a b i l i t i e s matched surgery? A l l t h r e e groups of h e a r t p a t i e n t s c o n t a i n e d a t l e a s t one p a t i e n t who had r e c e i v e d a coronary a r t e r y bypass. In the h e a r t d i s e a s e c o n t r o l group (n=20), the one p a t i e n t who had a bypass chose s u r g e r y i n the q u e s t i o n . Among p a t i e n t s with m i l d angina (n=15), f i v e p a t i e n t s had a bypass but o n l y two s e l e c t e d s u r g e r y as t h e i r o p t i m a l c h o i c e of treatments, w h i l e t h r e e s e l e c t e d drug therapy as the o p t i m a l treatment. Of some i n t e r e s t , a l l s i x p a t i e n t s w i t h s e v e r e angina (n=14) who had a l r e a d y had a bypass s e l e c t e d 154 s u r g e r y a g a i n as t h e i r p r e f e r r e d treatment outcome. I t i s important here to r e f l e c t back to Chapter 3 and the d i s c u s s i o n of p r e f e r e n c e r e v e r s a l . In the above d i s c u s s i o n of p r e f e r e n c e s f o r s u r g i c a l or drug treatment, p a t i e n t s chose a treatment based on the p r o b a b i l i t y of outcomes. The r e l i a n c e one may p l a c e on the a b i l i t y of p a r t i c i p a n t s i n a d e c i s i o n to demonstrate c o n s i s t e n c y was shown to be m i s p l a c e d because of the number of p a t i e n t s who were not c o n s i s t e n t i n t h e i r c h o i c e when the q u e s t i o n asked f o r a b i d f o r an outcome versus a d i r e c t c h o i c e . I f some p o l i c y s u g g e s t i o n s c o u l d be drawn from the t e n t a t i v e i n t e r p r e t a t i o n of p a t i e n t p r e f e r e n c e s f o r s u r g i c a l treament, they might focus on making s u r g e r y a v a i l a b l e f o r the s e v e r e l y i l l p a t i e n t who demonstrated a s t r o n g and c o n s i s t e n t p r e f e r e n c e f o r s u r g i c a l outcomes. In the p r e s e n t study, s i x t y per cent of p a t i e n t s with m i l d angina who had a bypass demonstrated a p r e f e r e n c e f o r drug therapy. T h i s may be an o v e r - t r e a t e d group. R e c a l l the d i s c u s s i o n i n Chapter 1 t h a t i d e n t i f i e d the p r e f e r e n c e s of p h y s i c i a n s and the economic i n c e n t i v e s t h a t c o u l d encourage treatment r a t h e r than non-treatment. An a n a l y s i s was a l s o conducted on treatment c h o i c e s u s i n g c l a s s i f i c a t i o n of study groups by d i a g n o s i s . The r e s e a r c h q u e s t i o n asked whether symptoms such as p a i n acted as an i n f l u e n c e on p a t i e n t c h o i c e s . 155 TABLE 4.8. D i a g n o s i s as an Independent V a r i a b l e s u r g i c a l c h o i c e drug c h o i c e t o t a l h e a l t h y s u b j e c t s 8 (55.3%) 7* (46.7%) 15 oth e r h e a r t 10 (50%) 10 (50%) 20 mi Id angina 8 (55.3%) 7 (46.7%) 15 seve r e angina 12 (85.7%) 2 (14.3%) 14 Notes: (a) One p a t i e n t i n the * group was a c t u a l l y i n d i f f e r e n t , (b) The d i f f e r e n c e between groups was not s i g n i f i c a n t . A n o t i c e a b l e , but not s t a t i s t i c a l l y s i g n i f i c a n t i n f l u e n c e of severe angina on treatment c h o i c e appeared as 85% of t h i s group chose s u r g e r y over drug therapy. There was a l s o no s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e i n the r a t e of s u r g i c a l versus m e d i c a l c h o i c e s f o r h e a l t h y s u b j e c t s , p a t i e n t s w i t h o t h e r forms of h e a r t d i s e a s e or p a t i e n t s with m i l d a n g i n a . The c l i n i c a l i m p l i c a t i o n s of t h i s f i n d i n g suggest t h a t p a t i e n t p r e f e r e n c e s may be independent of symptoms except f o r those w i t h severe p a i n or d i s a b i l i t y and should t h e r e f o r e be e l i c i t e d b e f o r e the d e c i s i o n to t r e a t i s made. 10.0. Summary T h i s chapter has shown t h a t p a t i e n t age i s not a s t r o n g p r e d i c t o r of i n t e r e s t i n or w i l l i n g n e s s to consume h e a l t h c a r e s e r v i c e s a s s o c i a t e d with coronary a r t e r y d i s e a s e . P a i n has 156 appeared as a v a r i a b l e capable of i n f l u e n c i n g an i n c r e a s e d w i l l i n g n e s s to seek treatment and to wait f o r treatment deemed to be of v a l u e to the p a t i e n t . No p a t i e n t s were o f f e r e d a cure or a lengthened l i f e by t a k i n g treatment. P r e v i o u s e x p e r i e n c e w i t h the h o s p i t a l system a c t e d to i n c r e a s e the t o l e r a n c e of w a i t i n g as w e l l as the a v e r s i o n to s u r g e r y among p a t i e n t s who had a l r e a d y had a bypass (CABG). P a t i e n t s who had no e x p e r i e n c e w i t h major s u r g e r y appeared more anxious to be t r e a t e d . The r e s u l t s r e p o r t e d i n t h i s c h apter suggest t h a t p a i n and d i s a b i l i t y may be important v a r i a b l e s d e t e r m i n i n g p a t i e n t p r e f e r e n c e s f o r treatment of coro n a r y h e a r t d i s e a s e . 11.0. L i m i t a t i o n s of the Study The g e n e r a l i z a b i l i t y of the f i n d i n g s of t h i s study has been l i m i t e d by a number of f a c t o r s i n c l u d i n g s e l e c t i o n b i a s , s m a l l sample s i z e , and o n l y p a r t i a l r e p l i c a t i o n of oth e r s t u d i e s . In Chapter 2, a d i s c u s s i o n of s e l e c t i o n of s u b j e c t s i d e n t i f i e d the low response r a t e among ambulatory p a t i e n t s r e c e i v i n g treatment i n the C a r d i o l o g y D i v i s i o n of the Vancouver General H o s p i t a l . D i r e c t r e c r u i t i n g of p r e s e l e c t e d p a t i e n t s by h o s p i t a l c a r d i o l o - g i s t s d i d not produce response r a t e s as high as those i n other s t u d i e s (Torrance e t . a l . , 1982). P a t i e n t s w i l l i n g to p a r t i c i p a t e i n the q u e s t i o n n a i r e appeared to be more l i t e r a t e than the average p a t i e n t / i n t r o s p e c - t i v e , i n t e r e s t e d i n medical d e c i s i o n making, had s t a b l e angina or 157 other h e a r t d i s e a s e , and had seen t h e i r c a r d i o l o g i s t more than once. T h i s group of p a t i e n t s demonstrated v u l n e r a b i l i t y to a number of e r r o r s of judgement. Although the study sample was b i a s e d by p a t i e n t s w i t h a ' b e t t e r than average' l e v e l of f u n c - t i o n , i t appears l i k e l y t h a t p a t i e n t s with u n s t a b l e angina, a r e c e n t m y o c a r d i a l i n f a r c t i o n , or a need to make a prompt t r e a t - ment c h o i c e w i l l be j u s t as v u l n e r a b l e , or even more so. P a t i e n t s who have been h o s p i t a l i z e d f o r treatment w i l l a l s o have l e s s c o n f i d e n c e , more a n x i e t y , and p r o b a b l y more p a i n ; a l l v a r i a b l e s t h a t reduce the l i k e l i h o o d of r a t i o n a l d e c i s i o n making. These p a t i e n t s may have a g r e a t e r need than ambulatory p a t i e n t s f o r a s t r u c t u r e d , s e q u e n t i a l method of e x p r e s s i n g a treatment p r e f e r e n c e . A r e l a t e d sample b i a s was due to the s e l e c t i o n of h e a l t h y s u b j e c t s from a s p o r t s c l u b whose members were pro b a b l y h e a l t h i e r than average. The l i f e s t y l e r i s k f a c t o r s i d e n t i f i e d i n the s u b j e c t ' s m e d i c a l h i s t o r y were n o t i c e a b l y d i f f e r e n t between the p a t i e n t s and the h e a l t h y s u b j e c t s . No h e a l t h y s u b j e c t smoked or was overweight, a l t h o u g h some s t a t e d t h a t t h e i r jobs were s t r e s s - f u l . Almost a l l p a t i e n t s w i t h moderate or s e v e r e h e a r t d i s e a s e were c u r r e n t l y or had been heavy smokers and many admitted to b e i n g ' h e a v i e r than they s h o u l d be'. S i n c e l i f e s t y l e r i s k f a c t o r s have been shown to p l a y a s i g n i f i c a n t r o l e i n the development and ' s e v e r i t y of c o r o n a r y h e a r t d i s e a s e , the use of r e c r e a t i o n a l a t h l e t e s was c o n s i d e r e d to be a j u s t i f i a b l e c h o i c e . 158 A second l i m i t a t i o n of the s t u d y was t h a t i t d i d not a t tempt to r e p l i c a t e p r e v i o u s s t u d i e s . S e v e r a l a c c l a i m e d and i m p o r t a n t s t u d i e s i n m e d i c a l d e c i s i o n making ( M c N e i l e t . a l . , 1978; M c N e i l e t . a l . , 1982; and P a u k e r , P a u k e r , and M c N e i l , 1981) s e r v e d as the f o u n d a t i o n f o r a number of p r e f e r e n c e q u e s t i o n s , but no q u e s t i o n s were a c t u a l l y r e p l i c a t e d . In a d d i t i o n , q u e s t i o n s d e v e l o p e d by o t h e r s (Kahneman and T v e r s k y , 1979, 1984; L i c h t e n s t e i n and S l o v i c , 1971) u s i n g money b e t s were not a p p r o p r i a t e f o r t r e a t m e n t c h o i c e s , and a d i f f e r e n t ' c u r r e n c y ' was c r e a t e d to t e s t f o r the p r e s e n c e of e r r o r s o f judgement p r e v i o u s l y d e m o n s t r a t e d by c h o i c e s i n v o l v i n g money. As a r e s u l t of u s i n g a 'new c u r r e n c y ' , r e f e r e n c e to terms i d e n t i f y i n g e r r o r s of judgement s u c h as p r e f e r e n c e r e v e r s a l may be m i s p l a c e d . However , the p u r p o s e of the s t u d y was to i d e n t i f y e r r o r s of judgement t h a t c o u l d i n f l u e n c e a p a t i e n t ' s a b i l i t y to e x p r e s s a t r u e p r e f e r e n c e . D e m o n s t r a t i n g s u c h an e r r o r w i t h more g e n e r a l u n i t s p r o v i d e d an o p p o r t u n i t y to i n c r e a s e t h e scope of u n d e r s t a n d i n g of d e c i s i o n making i n cases where d o l l a r s were not the a p p r o p r i a t e measure . A t h i r d l i m i t a t i o n of the s t u d y was due to the h y p o t h e t i c a l n a t u r e of the q u e s t i o n s . F o r e x a m p l e , s u b j e c t s were asked to s t a t e the per c e n t of t h e i r ' r e t i r e m e n t income' they would be p r e p a r e d to exchange f o r a b e t t e r p o s i t i o n on a w a i t i n g l i s t than the p o s i t i o n t h e y had been a s s i g n e d . S u b j e c t s were t o l d t h a t w a i t i n g c a r r i e d a 5% r i s k of h e a r t a t t a c k . T h i s q u e s t i o n was u s e d , not o n l y as a s t r a t e g y to p r o b e w a i t i n g , but as a s t r a t e g y 159 to t r y to understand response to r i s k . The study i d e n t i f i e d p a t i e n t s f o r whom treatment had a low or even n e g a t i v e v a l u e as measured by t h e i r w i l l i n g n e s s to 'pay' to be t r e a t e d sooner. P a t i e n t s demonstrated v e r y d i f f e r e n t responses: the 5% r i s k c o m p l e t e l y d e t e r r e d some p a t i e n t s from w a i t i n g , w h i l e o t h e r s f e l t t h i s r i s k to be i n c o n s e q u e n t i a l . As a r e s u l t of the a b i l i t y of these q u e s t i o n s to d i f f e r e n t i a t e p a t i e n t s who were w i l l i n g to bear r i s k , the h y p o t h e t i c a l nature of the q u e s t i o n s was f e l t to be j u s t i f i e d . F i n a l l y , the r o l e of the r e s e a r c h e r as a non-medical p a r t i c i p a n t i n medical d e c i s i o n making was p e r c e i v e d as a p o t e n t i a l l i m i t a t i o n i n the st u d y . P a t i e n t s and p h y s i c i a n s a re the u s u a l d e c i s i o n makers. However, as Chapter 1 has shown, some p h y s i c i a n s do not i n v o l v e p a t i e n t s i n the c h o i c e of a treatment. Thus, the r e s e a r c h e r developed a r o l e t h a t was t h r e a t e n i n g to n e i t h e r the p a t i e n t nor the p h y s i c i a n . Due to the p r e l i m i n a r y nature of the pr e s e n t study t h i s r o l e was supported by the D i v i s i o n of C a r d i o l o g y and the E t h i c s Committee of the U n i v e r s i t y of B r i t i s h Columbia. In a d d i t i o n , many p a t i e n t s f e l t l e s s c o n s t r a i n e d about 'making a mistake' w i t h a par a - m e d i c a l person than they d i d w i t h a p h y s i c i a n . The r e s e a r c h e r was d e l i b e r a t e l y not informed i n advance of any d e c i s i o n s the p h y s i c i a n or p a t i e n t had p r e v i o u s l y made r e g a r d i n g treatment. Thus the q u e s t i o n n a i r e was not used to c o n f i r m any d e c i s i o n s , but to e x p l o r e the p a t i e n t ' s p r e f e r e n c e s f o r f u t u r e t r e a t m e n t s . 160 11.0. C o n c l u s i o n s S e v e r a l t r e n d s have been i d e n t i f e d by the r e s u l t s of the study. F i r s t , p r e v i o u s l y i d e n t i f i e d e r r o r s of judgement have been demonstrated by p a t i e n t s w i t h h e a r t d i s e a s e and by h e a l t h y s u b j e c t s making a treatment c h o i c e 'as i f they had h e a r t d i s e a s e . These e r r o r s i n c l u d e d f r a m i n g (the wording of the q u e s t i o n i n f l u e n c e d c h o i c e ) , p r e f e r e n c e r e v e r s a l (whether the outcome was chosen or b i d f o r i n f l u e n c e d p r e f e r e n c e ) , asymmetric c h o i c e ( c h o i c e s d i f f e r when t h e r e i s a chance to g a i n or to l o s e ) , and v i o l a t i o n of the s u b s t i t u t i o n axiom (when a c h o i c e was changed by the same f a c t o r as a competing c h o i c e i t was not s e l e c t e d a second t i m e ) . S u b j e c t s i n the study who were h e a l t h y e x h i b i t e d a d i f f e r e n t p a t t e r n of r i s k a v e r s i o n than s u b j e c t s w i t h s e r i o u s h e a r t d i s e a s e . These r e s u l t s suggest t h a t c o n s i d e r a b l e m e r i t may a c c r u e to s t u d y i n g d e c i s i o n making i n a r e a l i s t i c environment even though such s t u d i e s may be more d i f f i c u l t and time consum- i n g . H e a l t h (and l i f e ) r i s k s p r e v i o u s l y f a c e d by p a t i e n t s demonstrated a p o s i t i v e r e l a t i o n s h i p to the c h o i c e of a treatment w i t h an u n c e r t a i n outcome. For example, p a t i e n t s with diagnosed h e a r t d i s e a s e were more r i s k a v e r s e than p a t i e n t s with h e a r t d i s e a s e accompanied by a h e a r t a t t a c k . The g r e a t e s t r i s k seekers were p a t i e n t s w i t h h e a r t d i s e a s e , a p r e v i o u s h e a r t a t t a c k and a c o r o n a r y bypass. 161 S e v e r a l expected trends were not demonstrated. Older s u b j e c t s d i d not e x h i b i t d i f f e r e n t treatment p r e f e r e n c e s than younger s u b j e c t s . S i n c e o n l y o n e - f i f t h of the s u b j e c t s were women, no d i f f e r e n c e s due to sex c o u l d be i d e n t i f i e d . P r e v i o u s treatment d i d not appear to i n f l u e n c e f u t u r e c h o i c e s . For example, l e s s than h a l f of the p a t i e n t s who had r e c e i v e d a c o r o n a r y bypass s e l e c t e d i t (based on outcome p r o b a b i l i t i e s ) as a p r e f e r r e d f u t u r e treatment. F i n a l l y , the study has demonstrated t h a t p a t i e n t s can express a p r e f e r e n c e f o r treatment. As more i s known about e r r o r s of judgement, h e a l t h p r o f e s s i o n a l s can improve methods of communicating w i t h p a t i e n t s and a s s i s t p a t i e n t s to p a r t i c i p a t e i n treatment d e c i s i o n s . 13.0. O p p o r t u n i t i e s f o r F u r t h e r Research The p h y s i c i a n s who p e r m i t t e d t h e i r p a t i e n t s to p a r t i c i p a t e i n the p r e s e n t study have expressed an i n t e r e s t i n the development of the q u e s t i o n n a i r e i n t o a t o o l c a p a b l e of a c t u a l l y h e l p i n g p a t i e n t s express a p r e f e r e n c e f o r treatment. In order to c r e a t e such a t o o l , refinement of q u e s t i o n s and t e c h n i q u e s would be r e q u i r e d i n v o l v i n g p a t i e n t s w i t h u n s t a b l e as w e l l as s t a b l e a n g i n a . Ambulatory p a t i e n t s as w e l l as those i n h o s p i t a l would need to p a r t i c i p a t e i n t e s t i n g e x i s t i n g q u e s t i o n s . Involvement of t h e ' p h y s i c i a n i n t h i s d e c i s i o n would add to the u n derstanding 162 of such a t o o l i n f u r t h e r i n g p a t i e n t p a r t i c i p a t i o n i n medical d e c i s i o n making. F u r t h e r t e s t i n g of the q u e s t i o n n a i r e w i t h l a r g e r groups would a l s o be of v a l u e . In a d d i t i o n , one would hope to encourage a h i g h e r response r a t e among the p a t i e n t s i n a c a r d i o l o g y p r a c t i c e . The r o l e of the r e s e a r c h e r i n t h i s study was developed to pose a t h r e a t to n e i t h e r the p a t i e n t s nor the p h y s i c i a n s . E v a l u a t i n g the p o t e n t i a l r o l e of a nurse p r a c t i t i o n e r or o t h e r p a r a - m e d i c a l h e a l t h p r o f e s s i o n a l would a l s o be of i n t e r e s t . The p a t i e n t s i n the p r e s e n t study i n d i c a t e d p o s i t i v e f e e l i n g s towards e x p r e s s i n g p r e f e r e n c e s to a ' n e u t r a l ' p e r s o n . F u r t h e r work toward u n d e r s t a n d i n g e r r o r s of judgement would i n c r e a s e the a b i l i t y of h e a l t h p r o f e s s i o n a l s to a v o i d s i t u a t i o n s where such e r r o r s c o u l d endanger the e x p r e s s i o n of a p a t i e n t ' s t r u e p r e f e r e n c e s . Although most of the t h e o r e t i c a l development of t h i s f i e l d i s underway i n p s y c h o l o g y and economics, i t s a p p l i c a t i o n to medicine i s s i g n i f i c a n t . One has o n l y to r e c a l l t h a t about o n e - t h i r d of every p r o v i n c i a l budget i s devoted to h e a l t h c a r e . F i n a l l y , i t i s important to acknowledge the p o t e n t i a l i n f l u e n c e of r e s e a r c h b i a s i n the d e l i v e r y of the q u e s t i o n n a i r e and a n a l y s i s of d a t a . A r e s e a r c h e r s e t t i n g out to support a t h e o r y may be more l i k e l y to f i n d such e v i d e n c e than a r e s e a r c h e r s e t t i n g out to f i n d c o n t r a d i c t i o n s to e s t a b l i s h e d t h e o r y . 163 E f f o r t s must be made by r e s e a r c h e r s to i n t e r p r e t e vidence without b i a s , and i n the case of competing paradigms, to s t r i v e to be o b j e c t i v e r e g a r d i n g the a b i l i t y of each paradigm to o f f e r a model f o r u n d e r s t a n d i n g human b e h a v i o u r . 14.0 F i n a l Comments As a case study of m e d i c a l d e c i s i o n making, t h i s r e s e a r c h s u f f e r s from a s m a l l sample s i z e but compensates f o r t h i s with a broad spectrum of data c o l l e c t e d on each s u b j e c t . E f f o r t s to understand p a t i e n t p r e f e r e n c e s under d i f f i c u l t c o n d i t i o n s have been based on p r e v i o u s work i n m e d i c a l d e c i s i o n making as w e l l as o t h e r d i s c i p l i n e s . Attempts to d i f f e r e n t i a t e the treatment p r e f e r e n c e s of p a t i e n t groups d i d , on a number of o c c a s i o n s , produce s t a t i s t i c a l l y s i g n i f i c a n t r e s u l t s . Although the f i n d i n g s d i d not always support p r e v i o u s r e p o r t s i n the l i t e r a t u r e , a g e n e r a l c o n c l u s i o n t h a t may be drawn from the study i s t h a t p r e f e r e n c e s are s i t u a t i o n s p e c i f i c . However, r e p l i c a t i o n of these q u e s t i o n s as w e l l as those w i t h n o n - s i g n i f i c a n t f i n d i n g s would be u s e f u l w i t h l a r g e r samples. The U n i v e r s i t y of B r i t i s h Columbia O f f i c e of Research Services B85-081 BEHAVIOURAL SCIENCES SCREENING COMMITTEE FOR RESEARCH AND OTHER STUDIES INVOLVING HUMAN SUBJECTS C E R T I F I C A T E of A P P R O V A L INVESTIGATOR: UBC DEPT: TITLE: NUMBER: CO-INVEST: APPROVED: MacCrimmon, K.R. COMM & BUSINESS ADMIN Patient p a r t i c i p a t i o n in the d e c i s i o n of coronary bypass surgery B85-081 Vertinsky, I. MAY 27 1985 Fulton, M.J. The protocol d e s c r i b i n g the above-named project has been reviewed by the Committee and the experimental procedures were found to be acceptable on e t h i c a l grounds for research i n v o l v i n g human subjects. Screening Committee THIS CERTIFICATE OF APPROVAL IS VALID FOR THREE YEARS FROM THE ABOVE APPROVAL DATE PROVIDED THERE IS NO CHANGE IN THE EXPERIMENTAL PROCEDURES 165 T H E UNIVERSITY OF BRITISH COLUMBIA FACULTY OF MEDICINE y F. Mizgala, M . D . , F.R.C.P.(C), F . A . C . C . :ssor of Medicine, I, Division of Cardiology, A R T M E N T OF MEDICINE, Heather Street, ouver, B.C. V5Z 3J5 June 6, 1985 Marian Jane Fulton Doctoral Candidate i n t o D i s c i p l i n a r y Studies Faculty of Medicine and Faculty of Commerce and Business Administration The U n i v e r s i t y of B r i t i s h Columbia Vancouver, B.C. Dear Ms Fu l t o n : Dr. Kerr has submitted to me documentation r e l a t i n g to your pro j e c t e n t i t l e d "Patient P a r t i c i p a t i o n i n the Deci s i o n of Coronary Bypass Surgery". I hereby grant you f u l l a u t h o r i z a t i o n to carry out t h i s p r o j e c t among outpatients seeing members of the D i v i s i o n of Cardiology on the 3rd F l o o r of the Doctors' Residence. This approval w i l l be subject to obtaining w r i t t e n approval from the UBC E t h i c s Committee, as well as from the Vancouver General H o s p i t a l Research Committee. I have i n d i c a t e d to Dr. Kerr how t h i s second c o n d i t i o n might be f u l f i l l e d r a p i d l y without f u r t h e r delaying the start-up of your p r o j e c t . I t w i l l be our pleasure to co-operate with you i n t h i s i n t e r e s - t i n g p r o j e c t and we look forward to seeing the r e s u l t s . Yours s i n c e r e l y , c.c. Dr. C. R. Kerr 166 INTRODUCTION TO THIS QUESTIONNAIRE A note to p a r t i c i p a n t s : The purpose of t h i s r e s e a r c h p r o j e c t i s to gather i n f o r m a t i o n t h a t w i l l h e l p d o c t o r s to understand how p a t i e n t ' s p r e f e r e n c e s can i n f l u e n c e the kind of treatment chosen. T h i s c h o i c e can be ve r y important to he a r t p a t i e n t s because d i f f e r e n t treatments have v e r y d i f f e r e n t e f f e c t s . We are a s k i n g you to answer the q u e s t i o n s we have gi v e n you. A r e s e a r c h e r w i l l h e l p you with the q u e s t i o n s i f you wish. I f you do not wish to complete the q u e s t i o n n a i r e , or th e r e are some q u e s t i o n s you do not want to answer, t h a t ' s a l l r i g h t . S i n c e the answers are completely anonymous, no one w i l l know. T h i s c o n f i d e n t i a l i t y a l s o a l l o w s you to be co m p l e t e l y candid about your p r e f e r e n c e s . Some q u e s t i o n s ask you to answer yes or no, some ask you f o r "how much" of something, and some ask you to choose between two gambles. These q u e s t i o n s r e l a t e to he a r t d i s e a s e g e n e r a l l y , they do not ap p l y to you d i r e c t l y . There are no ' r i g h t * answers. We assume t h a t i f you answer the q u e s t i o n s t h a t you have g i v e n us your consent. We w i l l keep your answers c o n f i d e n t i a l by a s k i n g you not to w r i t e your name on the paper. When you have f i n i s h e d the q u e s t i o n s , the r e s e a r c h e r w i l l t a l k to you about them. I t i s not uncommon f o r a few people to f e e l some a n x i e t y about t h e i r own i l l n e s s a f t e r they t h i n k about being i n h o s p i t a l or being an i n v a l i d f o r some time. The r e s e a r c h e r w i l l answer your q u e s t i o n s about t h i s a l s o . 16 7 CONSENT FORM I, , authorize (name of patient) Dr. to inform Jane Fulton, M.Sc. that I have heart disease. I understand that my p a r t i c i p a t i o n in the University of B r i t i s h Columbia research project "Patient P a r t i c i p a t i o n in the Decision to Treat Coronary Heart Disease" i s voluntary. (signature of patient) page 1 16 8 PARTICIPATING IN DECISIONS INSTRUCTIONS: Please answer the following questions using the v i s u a l aids a v a i l a b l e . The researcher i s here to help you with any questions. HISTORY: age sex date Doctor's name Doctor's diagnosis Angina present not present Description of symptoms: -duration -onset a f t e r exercise -duration of r e l i e f Working status: health status: -other chronic i l l n e s s -other h o s p i t a l stays -other family i l l n e s s Family status: -mar i t a l - c h i l d r e n L i f e s t y l e r i s k f a c t o r s : -smoking h i s t o r y number of years smoked do you s t i l l smoke when did you quit -weight -stress 169 page 2 THE QUESTIONNAIRE NOTES: 1. In some questions you w i l l see the word 'chance' accompanied by a number such as 30%. This can be thought of as 30 people out of 100 people. 2. Some questions state that angina pain may be reduced for 2 years. These 2 years are part of the t o t a l number of years that you expect to l i v e . 3. When you are asked to make a choice, t r y to think of i t as being a f i n a l choice. If you choose treatment A now, you cannot have treatment B l a t e r . QUESTIONS: 1. How many years do you expect to l i v e ? years 2. Please i d e n t i f y how important the following aspects of hospital care are to you. Mark an 'X' on the l i n e below each statement. a) There i s no waiting l i s t for treatment. very important\ \ \ \ \ \not important b) Treatment in hospital takes longer than 2 weeks. very important\ \ \ \ \ \not important c) Angina pain is controlled by treatment. very important\ \ \ \ \ \not important 3. Would you agree to 2 months of mandatory bed rest at home i f your chances of completely eliminating angina pain for 2 years were: (answer yes or no) Chance of reducing angina pain for 2 years: yes/no 90% 70% 50% 30% 10% 1% 170 page 3 4. A f t e r a treatment f o r angina, some p a t i e n t s have no p a i n w h i l e some p a t i e n t s have p a i n twice as o f t e n as b e f o r e the t r e a t - ment.The numbers below are chances t h a t the treatment w i l l e l i m i n a t e angina p a i n f o r 2 y e a r s . Which of these groups would be a c c e p t a b l e to you? chance of no p a i n p a i n twice as o f t e n yes/no A. 90% 10% B. 70% 30% C. 50% 50% D. 30% 70% E. 10% 90% I f A i s not a good enough 'chance' f o r improvement, what chance would be a c c e p t a b l e ? If E i s a c c e p t a b l e , what lower chance i s not a c c e p t a b l e ? 5. In each of these q u e s t i o n s you have to spend weeks i n h o s p i t a l now f o r e l i m i n a t i n g p a i n l a t e r . You w i l l have p a i n w h i l e you are in the h o s p i t a l . To c o m p l e t e l y e l i m i n a t e angina p a i n : f o r 1 year , I would spend weeks f o r 5 y e a r s , I would spend weeks f o r the r e s t of my l i f e , I would spend weeks What would you be g i v i n g up i n order to spend these weeks i n h o s p i t a l ? 6. S t a t e how many weeks you would be prepared to s t a y i n h o s p i t a l to a c h i e v e the f o l l o w i n g outcomes: Outcome A: 98% chance of no angina p a i n f o r 2 years 2% chance of p a i n the same as i t i s now f o r 2 years A weeks Outcome B: 25% chance of no angina p a i n f o r 8 years 75% chance of p a i n the same as i t i s now f o r 8 years B weeks page 4 171 7. L i s t e d below are some h y p o t h e t i c a l procedures with r i s k s and b e n e f i t s l i s t e d , which one would you choose? Assume t h a t you cannot have both treatments. treatment group A: T h i s treatment c o m p l e t e l y e l i m i n a t e d angina p a i n f o r 2 years f o r 80% of p a t i e n t s ; 15% s t i l l had p a i n , and 5% d i e d i n h o s p i t a l . treatment group B; T h i s treatment c o m p l e t e l y e l i m i n a t e d angina p a i n f o r 2 years f o r 60% of p a t i e n t s , 40% had the same p a i n they had b e f o r e the treatment, no p a t i e n t s treatment. d i e d because of the no angina same p a i n r i s k of death treatment A 80% treatment B 60% 15% 40% 5% 0% A or B or no p r e f e r e n c e I f you chose A, what % of group B would have to have p a i n r e l i e f to get you to j o i n the group? % If you chose B, what would the outcome i n A have to be to get you to j o i n the group? 8. These treatment groups have d i f f e r e n t outcomes, which group do you p r e f e r ? no angina same p a i n r i s k of death treatment A 70% 15% 15% treatment B 55% 35% 10% A or B or no p r e f e r e n c e What outcomes d i d you focus on i n making your c h o i c e ? 172 page 5 9. Listed' below are two treatments with d i f f e r e n t long term outcomes. These outcomes have d i f f e r e n t r i s k s . Choose one. Assume that i f you survive the treatment you w i l l l i v e as long as you expect, but you w i l l have angina pain. treatment group A: This treatment completely eliminated angina pain f. o r 6 years for 90% of patients; 10% of the patients suffered complications of treatment and died. treatment group B: This treatment completely eliminated angina pain for 5 years for a l l patients. A or B or no preference If you chose A, then how many more months would B need to get you to choose B? 1 month 2 months 3 months 4 months 5 months 6 months , more than 6 months? \ how many more months would A need to get you to 1 month 2 months 3 months 4 months 5 months 6 months , more than 6 months? 10. How long can you exercise before angina pain? How many blocks can you walk without angina? Choose between the following two treatments: treatment A: 50% chance of no angina pain a f t e r any amount of exercise, and a 50% chance of pain the same as i t is now; treatment B: twice as much exercise for sure with no angina pain. A: 50/50 chance B: twice as much for sure If you chose B, choose A? 173 page 6 11. Choose between the f o l l o w i n g two t r e a t m e n t s : treatment A: 50% chance of no angina p a i n a f t e r any amount of e x e r c i s e , 50% chance of not being a b l e to e x e r c i s e at a l l ; treatment B: a c e r t a i n l o s s of 1/2 your c u r r e n t e x e r c i s e time b e f o r e angina p a i n the same as i t i s now. A: 50/50 chance B: 1/2 l o s s f o r sure 12. For t h i s q u e s t i o n use the number of years you expect to l i v e as the years f r e e of angina p a i n . S t a t e how many years of l i f e you would take (with angina l i k e you have now) i n order to be i n d i f f e r e n t between the years w i t h angina and the f o l l o w i n g gambles. Would you agree to take a p i l l t h a t o f f e r e d a 98% chance of complete r e c o v e r y from your h e a r t d i s e a s e and a 2% r i s k of death? yes no Would you agree to exchange a l l the years you expect to l i v e w i t h h e a r t d i s e a s e f o r one year of p e r f e c t h e a l t h ? yes no Choice #1: T h i s treatment i s an e x p e r i m e n t a l p i l l t h a t has a 50% chance of c o m p l e t e l y e l i m i n a t i n g angina p a i n f o r your l i f e t i m e and a 50% chance of immediate death. Take years of l i f e f o r sure i n s t e a d of the p i l l . C hoice #2: T h i s p i l l has a 75% chance of complete r e c o v e r y f o r your l i f e t i m e and a 25% chance of death. Take years of l i f e f o r sure i n s t e a d of the p i l l . C hoice #3: T h i s p i l l has a 25% chance of complete r e c o v e r y f o r your l i f e t i m e and a 75% chance of death. Take years of l i f e f o r sure i n s t e a d of the p i l l . 174 page 7 13. P l e a s e choose between the f o l l o w i n g outcomes of a treatment f o r your angina. When you f i n i s h the treatment assume t h a t you must l i v e your expected l i f e w ith a n g i n a . Treatment A: 98% chance of 2 years w i t h no angina p a i n , and a 2% chance of p a i n the same as i t i s now. Treatment B: 25% chance of 8 years w i t h no angina p a i n , and a 75% chance of p a i n the same as i t i s now. A or B of I n d i f f e r e n t to A or B If you chose A, c o n s i d e r the f o l l o w i n g o f f e r : Treatment C: 100% chance of no p a i n f o r 12 months, choose A or C If you chose A, how many months need to be added to C to get you to choose C? months If you chose C, how many months l e s s than 12 would you accept to r e t a i n C? months If you chose B, c o n s i d e r the f o l l o w i n g o f f e r : Treatment D: 50% chance of 5 years w i t h no angina p a i n , 50% chance of p a i n the same as i t i s now. choose B or D I f you chose B, what would the chances i n D have to be to get you to choose D? % If you chose D, how would the chances i n D have to change to get you to choose B? 14.To determine how many d o l l a r s you have f o r t h i s q u e s t i o n , s t a t e how much money you need f o r 1 year of r e t i r e m e n t , and make tha t your annual income. Income = $ You are on a 6 month w a i t i n g l i s t f o r h e a r t s u r g e r y . I f other p o s i t i o n s on the l i s t were a v a i l a b l e , how much money would you be w i l l i n g to exchange f o r the p o s i t i o n s l i s t e d below. I f you wait there i s a 5% chance you might have a h e a r t a t t a c k . 175 page 8 To wait 3 months I would t r a d e $ %) To wait 1 month I would t r a d e $ %) To not wait at a l l I would t r a d e $ %) 15. You are on a 6 month w a i t i n g l i s t f o r h e a r t s u r g e r y , and you are 1st on the l i s t . W a i t i n g l o n g e r has a 5% chance t h a t you w i l l have a h e a r t a t t a c k . The same money i s a v a i l a b l e f o r everyone on the l i s t as i s a v a i l a b l e f o r you. No one i s s i c k e r than you a r e . How much money would you want from the person t a k i n g your p l a c e i f you were to wait 1 week? $ would you trade? I f you waited 3 months? 16. Choose between the f o l l o w i n g h o s p i t a l s o f f e r i n g treatment: (Assume t h a t the treatment has s i d e e f f e c t s t h a t prevent t r y i n g another f o r at l e a s t 2 years) While you wait you bear a 5% r i s k of a h e a r t a t t a c k . H o s p i t a l A: W a i t i n g time i s 6 months ( a l l p a t i e n t s have angina fo r 6 months), a f t e r the treatment a l l p a t i e n t s have no angina p a i n f o r 4 y e a r s ; H o s p i t a l B: No w a i t i n g time, p a t i e n t s have no angina f o r 3 y e a r s . A: wait 6 months B: no wait If you chose h o s p i t a l A, how long would angina p a i n have to be e l i m i n a t e d to get you to choose B? $ If you waited 6 months? $ If you chose h o s p i t a l B, how long would angina p a i n have to be e l i m i n a t e d to get you to choose A? 176 page 9 17. A f t e r a treatment f o r angina, some p a t i e n t s have p a i n twice as o f t e n as b e f o r e the treatment w h i l e some p a t i e n t s have no more p a i n . The numbers below are chances t h a t the treatment w i l l cause angina p a i n to occur twice as o f t e n . Which of these groups would be a c c e p t a b l e to you? p a i n t wice as o f t e n chance of no p a i n yes/no 10% 90% / 30% 70% / 50% 50% / 70% 30% / 90% 10% / PATIENT'S COMMENTS: APPENDIX II 177 VISUAL AIDS for subjects participating in the Vancouver General Hospital Coronary Heart Disease Study. 178 Question 3 100% CHANCE OF REDUQNG SYMPTOMS 179 Question 4 & 17 100% CHANCE OF SYMPTOMS OCCURING TWICE AS OFTEN AND CHANCE OF NO MORE SYMPTOMS 10% ~§U%~ 30% "75%" 50% " 5 W 70% 30% Q u e s t i o n 6 & 13 180 25% CHANCE OF 8 YEARS FREE FROM SYMPTOMS 181 S e n s i t i v i t y A n a l y s i s f o r Question 13 182 FOR 5 YEARS 183 Question 7 TREATMENT A no symptoms same symptoms die in hospital 80% 15% 5% TREATMENT B no symptoms same symptoms 60% 40% TREATMENT B. OVERLAY 184 e s t i o n 8 TREATMENT A no symptoms same symptoms - die in hospital 75% 15% 15% TREATMENT B no symptoms same symptoms 55% 35% 10% die in hospital TREATMENT B. 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