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Patient participation in the decision to treat coronary artery disease Fulton, Marian Jane 1986

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PATIENT PARTICIPATION IN THE DECISION TO TREAT CORONARY ARTERY DISEASE  By MARIAN JANE  B.H.Ec.  FULTON  ( h o n o u r s ) , The U n i v e r s i t y  Professional M.Sc,  of B r i t i s h  Columbia,  1969  C e r t i f i c a t e i n E d u c a t i o n , The U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1979  The U n i v e r s i t y  A THESIS SUBMITTED  of B r i t i s h  Columbia,  1982  IN PARTIAL FULFILLMENT OF  THE REQUIREMENTS OF THE DEGREE OF DOCTOR OF PHILOSOPHY IN THE FACULTY OF GRADUATE STUDIES The  We  Department o f I n t e r d i s c i p l i n a r y S t u d i e s  a c c e p t t h i s t h e s i s as sronforming t o t h e r e q u i r e d  standard  THE UNIVERSITY OF BRITISH COLUMBIA August (g)  1986  M a r i a n Jane F u l t o n ,  1986  or-  In  presenting  this  degree at the  thesis in  University of  partial  fulfilment  of  British Columbia, I agree  freely available for reference and study. I further copying  of  department  this or  thesis for by  his  or  the  representatives.  that the  for  an advanced  Library shall make it  agree that permission for extensive  scholarly purposes may be her  requirements  It  is  granted  by the  understood  that  publication of this thesis for financial gain shall not be allowed without permission.  Department of  Interdisciplinary  The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3  DE-6(3/81)  Studies  head of copying  my or  my written  i i  ABSTRACT  This ought the  this  length  and  quality  potential errors  expression  of a true  exploration  situations choices, are  are  of of  affected  that by  preferences  expressed  by b i d s  versus  improved  position  reluctant  patients' age was  in  to s e l l  not  a  were  Generally,  Recommendations  vulnerable  towards to  errors  sketched.  were  influence  real  they  made t o  i n t e r f e r e with The r e s u l t s o f decision  make  making  inconsistent preferences  choices  change i n  of  been  patients  willing  to  pay  f o r an  list  f o r treatment, but they  such  a position.  choices  factors  to  were  while  patterns  o f judgement.  situation Further  that  p a i n and of  situation  made f o r i m p r o v i n g  whose  were  An a n a l y s i s o f  system demonstrated  patient  preferences have  in  and t h e i r  to the health  contributing  patient  sensitivity  study  or trade  predictor  patients  and p o t e n t i a l l o s s .  on a w a i t i n g  age a n d e x p o s u r e  disability  have been  the  could  i n s i t u a t i o n s where  choices,  of p o t e n t i a l gain  could  by a p a t i e n t .  framing,  that  E f f o r t s were  that  people  reverse  that  lives.  judgement  preference  suggested  Participants  decisions  their  they  situations  very  on t h e n o r m a t i v e a r g u m e n t  to p a r t i c i p a t e i n treatment  explore the  s t u d y was b a s e d  choice.  specific. professional  makes  them  more  avenues f o r r e s e a r c h  ACKNOWLEDGEMENTS  I would Mitchell. Dr.  like  As C h a i r m a n o f my t h e s i s  Mitchell  criticism  offered  the  indebted  who,  a s members o f  guidance,  t o Dr. C h a r l e s the thesis  am  grateful  to  Vice-President Hospital,  Don R i c c i ,  their  Henry  the proposal  provided  i n this  along  with  allowed  and  for  The e n t h u s i a s m patients  was an  patients  direction for  Head, D i v i s i o n o f Dr.  the  Derek  Gellman,  study  General  and g r a n t e d  at the h o s p i t a l . Dr. V i c t o r to  and c o - o p e r a t i o n important  Schechter  a t t h e Vancouver  Dr. M i z g a l a ,  their  T.  I am  study.  Mizgala,  D i r e c t o r of Research  program,  and c o n s t r u c t i v e  and D r . M a r t i n  Hospital,  my  Program p o s s i b l e .  f o r p a t i e n t s t o be i n t e r v i e w e d  Kerr,  study.  and  who r e v i e w e d  permission Dr.  support,  committee  Dr.  C a r d i o l o g y , Vancouver General  Dr.  R. K e r r  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  committee and o f  t h a t made an I n t e r d i s c i p l i n a r y  also  the  t o acknowledge, above a l l o t h e r s , D r . Vance F.  participate  of these  factor  H u c k e l l , and  i n the  i n this  p h y s i c i a n s and success  of this  endeavour. I  would  like  to  MacCrimmon f o r r e v i e w i n g comments.  thank the  D r . D a n i e l Kahneraan and D r . K. R. questionnaire  I also appreciated  Thaler  from C o r n e l l  University  Fraser  University.  Others  the e a r l i e r and D r .  offering  and  making  valuable  remarks of Dr. R i c h a r d  Jack  Knetsch  from  welcome s u g g e s t i o n s f o r  Simon  i v improving were D r .  the  of  Shelby Brumelle,  I would observe  analysis  also  patient  like  the data Dr. W.T.  to thank  participation  emergency c o n d i t i o n s .  I am  C h a r l e s K e r r , Dr. V i c t o r i a  Dr.  Tom  Perry, J r . ,  The  Social  and  Dr.  Sciences  supported  this  Fellowship  Program.  I would  for  their  Blair  and  to  and  loving  my  in  real  Dr.  Bernstein,  Adam  who  Max  Dr.  the  report  Payayre.  allowed  me  decisions  to  under  Walters,  Michael  Moscovich,  Waldie. Humanities  research project like  Roch  treatment  to:  of  Research through  t o e x p r e s s my  Council  of  their Doctoral  gratitude  to  them  continued confidence.  Finally, Dr.  and  the p h y s i c i a n s  and  C a n a d a has  structure  Stanbury  grateful  Dr.  and  I would  Fulton  and  daughters, throughout.  like  to say  Margaret J e a n , Amy,  thank  Fulton Sarah  you for and  t o my  parents,  their Lila  who  encouragement; were  patient  V  TABLE OF CONTENTS Title  Page  i  Abstract  i i  Acknowledgements  i i i  CHAPTER 1 SECTION ONE: PATIENT PREFERENCES: t h e R a t i o n a l e 1.0  Introduction  1.1 T h r e e  Models  1.2 I n f o r m e d  1 of M e d i c a l Care  Consent  1.3 A t t r i b u t e s  9  of M e d i c a l D e c i s i o n Making  1.4 U n c e r t a i n t y i n C l i n i c a l of  4  Medicine:  12  a Component  Risk  16  1.5 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  1.6 Summary  SECTION TWO:  23  CORONARY HEART D I S E A S E : Epidemiology,  2.0 The C l i n i c a l 2.1 G r a d i n g  17  History  the Angina  2.2 The E p i d e m i o l o g y  and E c o n o m i c s  of Coronary  of Coronary  of Coronary  2.3 The P r o g r e s s i v e N a t u r e  History,  Heart  Heart  Heart  of Coronary  Disease  Disease  25 27  Disease  28  Heart  31  2.4 The C l i n i c a l  Background: Medical  2.5 The C l i n i c a l  Background: Coronary  2.6 The C l i n i c a l  Background: A n g i o p l a s t y  Disease  Therapy Bypass S u r g e r y  32 34 38  vi 2.7  The  Cost  of  Medical  2.8  The  Cost  of Coronary  2.9  The  Cost  of A n g i o p l a s t y  2.10  Conclusions  2.11  The  from  Research  CHAPTER 2  Therapy  i n Canada  40  A r t e r y Bypass G r a f t i n g  41 43  the C l i n i c a l  Discussion  Questions  44 47  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  3.0  Sampling  4.0  P a i n as  5.0  Introducing Subjects  6.0  The  7.0  Interviewer  8.0  P a t i e n t Assurance  62  9.0  Attributes  64  10.0  the Chapter  Strategy a Factor  Subject's  Measuring  51 i n D e c i s i o n Making to  the  56  Questionnaire  Role  of  i n the  Heart  Study  66  Strategies  11.1  Standard  11.2  Ranking  11.3  Time-Trade-Off  Gamble and  68 Comparisons  and,Preference  12.0  A d m i n i s t e r i n g the  13.0  The  14.0  Statistical  15.0  Conclusions  of  61  P a t i e n t Choice  Utility  56 59  Bias  I I . 0 Measurement  Use  51  69  Scaling  73 74  Questionnaire  Patient Preferences Analysis  74 Over  Time  76 77 78  vi i CHAPTER  3  THE  STUDY OF  1.0  Introduction  2.0  The  2.1 3.0  PATIENT PREFERENCES: E r r o r s o f  80  Certainty Effect:  Results of  Preference  3.2  D i s c u s s i o n of  of  Framing  4.2  Discussion  5.0  5.1 6.0  Questions  Preference  Reversal  91  Effect  93 96  of Framing  -  D i a g n o s t i c Groups  99 100  Discussion  103  Choice:  or  98 98  Substitution Effect  of Gains  85  Effects  Asymmetric  81  90  Conclusions  The  Aversion  Reversal  Formulation  D i s c u s s i o n of  4.4  Risk  85  Preference  the  4.1  4.3  Example o f  Reversal  Results  Framing:  an  Certainty Effect  3.1  4.0  Judgement  Choices  i n the  Domain  Losses  106  6.1  Discussion  110  6.2  Conclusions  112  7.0  Willingness-to-Pay  113  7.1  Results  7.2  Discussion  118  7.3  Conclusions  119  8.0  The  8.1  of W i l l i n g n e s s - t o - P a y  Endowment  Results  of  Effect Endowment  118  119 Effect  Questions  120  V I 11  8.2 C o n c l u s i o n s 9.0  Summary  123  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 , Characteristics, 1.0  Introduction  2.0  Investment  and Q u a l i t y o f L i f e  Demographic  Issues 125  i n Future  Health  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 3.0 V a l u e  of Risk  3.1 R e s u l t s  Avoidance  131  and D i s c u s s i o n  3.2 A n a l y s i s o f U t i l i t y 4.0 P r e f e r e n c e s 4.1 R e s u l t s  134  Curves  Aversion  No R i s k  and D i s c u s s i o n  5.1 V u l n e r a b i l i t y Previous  f o r Risk  f o r Morbidity with  Health  Variable  to the I n f l u e n c e of Framing Experience  as an  and D i s c u s s i o n Bypass  149  Experience  8.1 R e s u l t s  146  148  Choices  8.0 H e a l t h  145  146  7.0 The I n f l u e n c e o f C o r o n a r y A r t e r y on  143  Independent  Variable 6.1 R e s u l t s  142  144  5.0 P a t i e n t Age as an I n d e p e n d e n t  6.0  131  and R i s k  and D i s c u s s i o n  Avoidance  150 151  ix 9.0 H e a l t h  Experience  and C h o i c e  of Surgical  Treatment  153  10.0 Summary  155  11.0 L i m i t a t i o n s o f t h e S t u d y  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 F u t u r e 14.0 F i n a l  Research  161  Comments  162  APPENDIX I Certificate Ethics  from  the University  of B r i t i s h  Committee  164  Letter  of Permission  Letter  of Introduction to Subjects  Consent The  Columbia  Form  Questionnaire  from  Dr. Henry M i z g a l a and P a t i e n t s  165 166 167 168  APPENDIX I I Visual  Aids  BIBLIOGRAPHY  177  190  X  L I S T OF 1.1.  TABLES  Grading  of  Angina  of  Effort  by  the  Canadian C a r d i o v a s c u l a r S o c i e t y 1.2.  1.3.  1.4.  H o s p i t a l Stays  f o r Canadians  Heart  1978 f o r Canadians  Heart  1980-81  Disease,  Average Cost  with '  H o s p i t a l Stays  in 1.5.  Disease,  28  with 31  of A n t i a n g i n a l D r u g s  Canada  41  Summary o f Decision  30  Treatments  and  Outcomes  to T r e a t Coronary  the  Artery Disease  Preference  3.2.  Framing  3.3.  Substitution  Principle:  A l l Respondents  103  3.4.  Substitution  Principle:  Heart  104  3.5.  Substitution  Principle:  Healthy  Effects  for A l l Subjects  45  3.1.  and  Reversal  in  f o r A l l Heart  Study  91 Subjects  Disease  Groups  Subjects  Hospital Administrators  104  3.6.  Asymmetric  Choice  for A l l Patients  3.7.  Asymmetric  Choice  for A l l Healthy  3.8.  W i l l i n g n e s s t o Pay Healthy  110 Subjects  for A l l Patients  Compensation  4.1.  Investment  4.2.  Value  4.3.  Risk  118  Demanded  i n Future  of A v o i d i n g Aversion  110  and  Subjects  3.9.  97  121 H e a l t h by  Life  Scores  of  P a t i e n t Groups  Risk D i a g n o s t i c Groups  128 134 142  xi 4.4.  Myocardial  4.5.  The  Infarction  and  Waiting  Choices  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  on W a i t i n g  149  4.6.  Health  Experience  4.7.  Angina  Pain  4.8.  Diagnosis  L I S T OF  and  as  an  and  Risk  Risky  Avoidance  151  Choice  153  Independent V a r i a b l e  155  FIGURES  4.1.  Investment  4.2.  Risk  4.3.  Utility  of  Risk Aversion  f o r Healthy  4.4.  Utility  of  Risk  f o r Heart  i n Future  Aversion  Health  i n Heart  128  Study Groups  Aversion  136 Subjects  Utility Mild  4.6.  138 of  Risk  Aversion  for Patients  with  Angina  Utility  137  Disease  Controls 4.5.  148  of  139 Risk  Severe Angina  Aversion  for Patients  with 140  1  CHAPTER  1  PATIENT PREFERENCES: The  1.0  Introduction The  tion Its  Rationale  present  study  i n the  choice  emphasis  was  medical  those  questions,  the  choices  indicated waiting  Treatment were c h o s e n  nations  and  than of  of  and  health  any  the  of:  were  by  knowledge  potential To  posed  who  patients  morbidity, to  and  evaluate  e r r o r s of  others,  these  disease  First,  risk,  of  errors in  answer  heart  conditions.  developed  the  judgement  i n some  cases  in  care. with  reasons. in  loss  coronary  First,  C a n a d a , and  consumer  coronary  world  do  several potential  death  other  how  disease.  c o n t r i b u t i o n to  better  p a t i e n t s with  for patients  economic  by  participa-  artery  what  influence choices?  questions  i s a major  Second,  disability, activity  of  second,  patient  coronary  First,  reductions  f o r a number o f  disease  system.  of  choices  cause  for  made  involved  strength  than  be  simulated  identified  other  leading  preferences  Second,  and  previously  heart  can And,  study  e x p l o r a t i o n of  questions.  making  value  time.  an  treatment  two  under  the  direction  fields  a  preferences?  expressing  made  on  decision  patient  of  was  of  heart due  group of  disease to  time  1984) .  health  c a u s e s more  i n the I t has  is  treatment  i n the  away  disease  disease  hospital  resources  diseases  (Braunwald,  heart  heart  from  the for care  long-term productive  industrialized been  estimated  2 that  each  coronary  year heart  afflicted the  cost  of  the  dollar  five  disability  an  $50  it  billion  cost  coronary third  decisions  is a  for  health that  demanded  the  by  to  cost  the  If  the  1984). is  Quite  l o s s of  roughly  an  annual  apart  from  human l i f e  and  exploring  the  for  to  decisions  that  study  (1982).  First,  a  describes  the  treatment  alternative  such  patients  so  of  that as  the does  as  the  making  by  patients  patient's  the  coronary  in  heart  treatment of  physicians to  of  are  partici-  by  Keeney  research  outcomes  disease.  the  lives.  suggested  possible  rights  critics  'ought'  i s presented  for  non-treatment.  affect their  protocol  medical  treatments  Moreover,  obviously the  actual  participation  that  discussion  for  is  patient,  decision  follows  likelihoods  studying  patients.  n o r m a t i v e argument  present  for  d e c i s i o n making f o r  greater  promoting  The  compensating  States,  reason  for  care,  approach  i n the  the  disease  traditional  pate  United  from are  Canada  significant.  reason  risks  indicate  a  i n the  die  disease.  in  i s being  65  people  estimated  in  compelling  t r e a t i n g heart carry  and  disease  medical  of  (Braunwald,  disease,  improving  trends  movement,  that  this  important  in  disease  Current  of  heart  is  dollars is  i t causes of  causes year  age  2,000,000  disease  each  of  the  this  heart  one-tenth  under  additional  Treating  billion  possibility  choices  and  productivity  t o be  of  this  Americans  t r e a t i n g coronary  bill  A  i t .  nation  estimated  with  disease  with  l o s s of  American  200,000  of  that each  Randomized,  3 controlled  trials  offer  outcome d i f f e r e n c e s , method key  for  studies  judgement posed  heart  of  as  discussion  is  and  uncertainty, decision  This  discussion  affect  patients.  generate the  common  Third,  errors  o f human  f o r the questions of  the  study are  provides  the background f o r  of  of p a t i e n t medical  with  decision  illustrate while of  nature  a  brief  making. A  interaction,  current  decision  coronary  participation is  physician-patient  consent  the  patients  attitudes  review of r i s k , trees  of the d e c i s i o n s  i n medical physicians  make.  for  of  in  structure  describe  values  ties  the  i s described.  findings  the issue  participation,  making  patients  chapter  traditional  and  Second, the  reviewed.  a foundation  the  evolving  informed  patient  are  and  preferences  i t  evidence of  a r e drawn.  of t h i s  First,  of  autonomy, toward  Finally,  1.  epidemiological  preferences  to provide  treatment  disease  addressed  and  reviewed  remainder  study  studies  preferences  and c o n c l u s i o n s  The  best  patient  of patient  to p a t i e n t s .  reported  the  and s u c h  eliciting  are  the  provides  the a l t e r n a t i v e  losses  the r a t i o n a l e f o r e l i c i t i n g treatments  The a l t e r n a t i v e and  benefits,  tree.  The  health  treatments together  t h e key items of the t o o l of  decision  and  clinical  with  medical history  1 Coronary heart disease i s also disease and c o r o n a r y atherosclerosis. interchangeably i n the l i t e r a t u r e .  and  outcomes  called These  that  the p r o b a b i l i patient  decision of  patient  values, making -  coronary  heart  coronary artery terms a r e used  4 disease,  i t s epidemiology,  are  examined.  then  1.2.  Three Models  of M e d i c a l  Three models patient first the  allows  normal duty this  value  full  reasoned  comes  and p r u d e n t  Some a r g u e  states that  may that  the  potential physicians for  at  that  actually  vitz,  revealing harm  make u n i l a t e r a l  who s t a t e s :  ... p a t i e n t b u t we  (Shephard,  patient.  to inform  can  also  "We  make a  value the - the  to the patient  illness  The c o u n t e r this  the patient  decisions  1983).  o f an  supports  may c a u s e  these d e c i s i o n s  Seeking  Support  somehow weak o r i n e p t  evidence  who  1982).  privi-  " s e taside the  1983, p . 9 0 ) .  the gravity  the  clinical  cost  a c t s and  'therapeutic to  The  the dying."  the information  what p e r s o n a l  the  p h y s i c i a n and  physician  leeway  et.al.,  who a r e  harm  life  model,  f o r himself;  obligation  base  setting  i n the l i t e r a t u r e .  (1980, p . 16)  that  moral  patients  patient's  so  of those  little  this  (Harron  to  where t h e  the moral  decision  the frightened,  patient  In  from Barber  disclosure,  humane p r o t e c t i o n young,  upon.  of d i s c l o s u r e "  relevant  identified  model  the physician  model  care  be  patient  i s acted  i n the Canadian  Care  medical can  i s the passive  lege'  for  of  interaction  patient  and e c o n o m i c s  argument  and f u r t h e r  overshadows the  (Barber, about  to a  1980).  treatment  Most  options  on m a x i m i z i n g  the length  How  i s lengthened, or  that  patient,  is  life  not considered  p a r t i c i p a t i o n i n informed  of t h e  (Goroconsent  5 has  not been  ethics  the accepted  have  doctors  alone  patients" "In person  to  influenced decide  not have  critical  in  p. 94-95).  his  Patients  knowledge,  have  influenced  society of  these  and  that  i t is for  proper  f o r their  Pressures  depend,  rights  the  move  these  (Dougherty,  s i t u a t i o n s , on  i s seen  of ethics  t o have t h e  and  patient's  the  where  motives  t o make  rests  away  change  power  interests"  in  codes  with  In o t h e r words,  to  moments, t h e a v e r a g e  k n o w l e d g e and  her best  of  professional  who must  by t h e i n t e r e s t s  "the professional  The  of the  i n a complex  f o r t h e m a i n t e n a n c e and r e s t o r a t i o n in  are being served"  cultural  suspect  of l i f e ' s  t h e dependent p e r s o n .  a f i d u c i a r y agent  whose i n t e r e s t s  ...  right  codes o f  to protect  p r a c t i c a l p e r s o n a l autonomy  broad  Even  assumption  i n h i s c h o i c e s and a c t i o n s  person.  is  or  Special  been d e v e l o p e d  to uphold  dependent  care.  and t h e p r o f e s s i o n a l  power t o make d e c i s i o n s .  be  is  the r e q u i s i t e  choices  professional  duty  by " t h e  what  some o f t h e most  successful  rights  i n medical  ( B a r b e r , 1980, p . 2 9 ) .  does  1985,  been  norm  the  lives  (Dougherty,  from  the (persons)  1985, p . 9 5 ) .  t h i s model h a v e come f r o m a  "people many,  of  challenge  i f  not  authority  and  a l l , professionals  ( H a r r o n e t . a l . , 1983, p . 9 1 ) . The physician  second is  model  is  one o f  patient  p a t e r n a l i s t i c and t h e p a t i e n t  juvenile  cooperator.  practise  of  treating  cooperation assumes  " P a t e r n a l i s m ... g e n e r a l l y individuals  where t h e  the role of a refers  i n t h e way a f a t h e r  to the  treats h i s  6 children" are  (Beauchamp, 1981,  identified  in medical  as  a d e c i s i o n maker.  to  do  good,  patient's ences of  for  he  1977,  a patient not  to  procedures consumer ance of  the  education this  p. may  option  refuse  behalf  the  of  courage  often  uncertainties  treatment and  and  and  (Barber,  patients care  The  model  emerge,  describes  medical the  to  d e c i s i o n making  patient  has  right  consent  to  patient  participation  treatment.  to The  be  as  fully  shift  in medical  a  paternal-  that  of  the  1  treatment  i t is  the  diagnostic  However,  more  patient  toler-  demanding  an  active  1985).  patient participation, joint  informed  i n the  firm  order  of  (Hoffman,  way  in  reduced  are  a  is possible"  benefit  a  the  request  t o be  The  believe  risks  has  in health  recent  the  1980).  i n d e c i s i o n making most  30).  accept  communication  paternalism  p.  by  i n such  course  a  prefer-  "The  . . i t i s best  'for  to  the  as:  patient  1980,  Physicians  such  other  or  1  Thus,  1981).  no  role  'ought'  (Beauchamp,  the  no  one  sought  to  in Barber,  a primary  be  statements  to  paternalism  for overriding"  36).  presented  'on  and  neither  patient  are  have t h e  reveal  or  the  1984).  to  1982,  of  p r i n c i p l e that  be  cited  acts  (Collins,  by  aspects  justification  s t r e s s i n g that  as  physician  patient  role  has  the  treated  model  should  authoritative,  istic  best  this  f e e l s he  (Fisher,  for  of  permission  that and  expressed  Two  beneficence,  as  (Gorovitz,  person being  nor  Typical  care:  "invoked  autonomy  physician  137).  Beneficence,  is often  the  p.  venture and  relative  to  where freely  the give  importance  d e c i s i o n m a k i n g has  been due  of to  7 less and  emphasis  more e m p h a s i s  tion by  on t h e p r o f e s s i o n a l  (Harron,  Abram  polled  wanted  decision stated  on t h e p a t i e n t ' s  et.al.,  (1982)  t o know  made by a p h y s i c i a n . by  Dougherty  while  patients  strongest  by  this  model  of  personal  bioethics  notion  within of  of  references  philosophers  concerned  past  treatment  make a polled  decisions  have been toward  i n the medical modern  autonomy. feature  decade  i l l patients,  with  then  offered more, i f  d e c i s i o n making as p r o p o s e d  autonomy a p p e a r s  or to s e r i o u s l y  and  p a r t i c i p a t i o n model.  of patient  the  was d e m o n s t r a t e d  trend  autonomy has b e e n a p r o m i n e n t  literature  physicians  for joint  t o informa  72% o f t h e p u b l i c  reasons  the current  i s the protection  However, t h e  scarcity  argument  information  88% o f p h y s i c i a n s  somewhat m i x e d , a c c e p t a n c e o f t h e p a t i e n t The  that  wanted  A number o f good  (1985) t o s u p p o r t  shift  alternatives  a physician  believed  This  reported  treatment  with  they  that  to d i s c l o s e "  "right of access"  1983, p. 5 ) .  i n a survey  jointly  that  "duty  The  of the growing  (Doudera,  t o be as  1981).  less central to indicated  literature, medical  value  by t h e  than  i t i s to  practise  (White,  1983). The principle States ...  earliest  o f l a w was  Supreme  that  legal  every  right  to  1983,  p. 7 6 ) .  record  made by  C o u r t , who human b e i n g  t o autonomy a s a  Mr. J u s t i c e C a r d o z o  stated of adult  d e t e r m i n e what s h a l l The  o f a commitment  in  1 9 1 4 : "The r o o t  years  be done w i t h  qualification  of the United  added  and  premise i s  s o u n d mind  h i s own b o d y " by  'adult  has a (White,  y e a r s ' and  8 'sound m i n d ' ment  t o autonomy  (Abrams,  1982)  "...the or  a l l a y s the  .  Full  autonomy  illness"  communication In  "physicians  are  physicians, (Doudera,  i s to help  good  medical  degree  the patient  possible  of  chronic  consultants  must  where  in  injuries  o r d e c i s i o n making  terms  finally  ideal  a  of the  right of  to  decide  care  therefore  maintain h i s  the face  of the  to the patient  by a n y o n e o t h e r  and  degenerative  patients,  and  upon t h e i r  autonomous p e r s o n  to... give  their  autonomous and know: what  actions  hamper  commit-  may  than the diseases,  patients,  own b e s t  not  interests"  1981, p . 1 0 6 ) .  "Our  aspects  the  by u n q u a l i f i e d  i s not always p o s s i b l e ,  emergency m e d i c i n e ,  physician.  to  actually  autonomy  to  created  ( C a s s e l l , 1983, p . 1 5 1 ) . An e x a m p l e o f l i m i t e d autonomy  in  prevent  have  may  job of the physician  her  arises  that  problems  care"  or withhold  (Dougherty,  make r e a s o n a b l e i s being  compared  informed  1985,  choices,  done a n d  to a l t e r n a t i v e s ,  e n t a i l s that consent  p. 9 8 ) .  patients  why, t h e r i s k  patients over a l l To r e m a i n  have t h e r i g h t of the proposed  and t h e o u t c o m e s o f no t r e a t -  ment . The second  increasing reason  innovations extend  appear  life,  innovations personal,  for  role  of  increased i n medical  technological patient care,  advancement  participation.  the  potential  c o n t r o l b e h a v i o u r , and e n g i n e e r generate a  and  range  political  of  choices  considerations  i s the As more  increases  reproduction.  dependant (Evans,  to  Such  on  social,  1985).  Humane  medicine  in  this  participation Third,  the  chronic  contributors  patterns and  often  patient.  This  require leads  understand  to  t r y to  treatment lifetime  improved be  by  their  improve  three  by  'healer'  is  The  become t h e  on  the  the  treatment they are  compliance  developed  treatment  reason,  better  in  major  of  part  these of  finding  the that  outcomes.  When  more e a s i l y  moti-  with  the  choice  what  may  of be  a a  and s i d e - e f f e c t s .  aspects  the  diseases  and  persons.  Participation in  patient  of  patient-physician  Satisfaction  maintaining  maker;  fourth  i t .  information  change  commitment  condition  participation.  improved  decision  considerable  medication  Finally,  disease  mortality.  the  shared  many a f f e c t e d  of  generates  increases of  and  to  mutual p a r t i c i p a t i o n  vated  require  degenerative  to m o r b i d i t y  diseases  patients  will  i n d e c i s i o n m a k i n g by as  countries,  context  the  human  physician's  enhanced;  and  of  worth  i n t e r a c t i o n are  physicians of  professional  the  tends  patient  reputation  c o n s u m e r a l i e n a t i o n and  to  as  a  as  a  cynicism  is  reduced.  1.3.  Informed The  concept decision  Consent  medical of  profession  autonomy where t h e  himself,  regarding  has  traditionally  individual patient  e i t h e r h i s own  actions  challenged makes t h e or  the  the final  actions  10 of  others  t o w a r d s him.2  I n some c a s e s ,  individual  d e c i s i o n making  a serious  accident,  not  be c o n s i d e r e d  treatment  when  (Forrest,  1984).  ethically  bound  any  procedure  derives  fully  he/she If  is  attack.  s u f f e r i n g from  a patient  pain  consent The  'awareness o r  may  about illness  the p h y s i c i a n i s  from  term  the ' d i s c l o s u r e '  the  1  choice  or mental  i s competent,  'informed  such as  A patient  t o make a r a t i o n a l  carries a risk.3  and f r o m  the patient f o r  'informed  required  assent'  consent'  by t h e word  required  by t h e  * consent . 1  Informed sovereignty  consent  "physicians  people  i n general  vitz,  1982,  then medical physician entails, during  is  o r autonomy  cause:  mists  competent  t o seek  that  by c i r c u m s t a n c e s ,  a d i s a b l i n g heart  i t s meaning from  'informed', word  or  i s subverted  an i n d i v i d u a l ' s r i g h t t o  do  of  inform  choice.  justifiably If  intervention  must  procedure  that  Consent  the s o r t s of things  cannot  p. 3 8 ) .  a  do  the p a t i e n t  i s no l o n g e r the  patient  embodies is  to t h e i r t o one  the  risks  of  the  2 I n d i v i d u a l d e c i s i o n making, or c a l l 'consumer s o v e r e i g n t y ' .  important bepatients  another"  i s informed  a b o u t : what  treatment,  autonomy,  that  (Goro-  and c o n s e n t s ,  a s s a u l t , but s e r v i c e .  t h e a l t e r n a t i v e s a v a i l a b l e , the problems recovery,  consumer  The  the procedure t h a t may a r i s e and a n y  is  what  other  econo-  3 A risk i s defined a s 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 m e a s u r e d as d e a t h , continuing disability due to angina, or increased d i s a b i l i t y c a u s i n g work l o s s o r l i f e s t y l e c h a n g e .  11 reasonable a patient the  information  complete  provided  information consent,  now t o be j u d g e d not  which  to  about  evaluate  Alfidi  and  benefit  discomforts  even h a r s h "  out of  terms  232 p a t i e n t s  1971,  in  his refusal  i n the study  favour  that  of t r u l y  Evidence may n o t want their  this  procedures  i s indeed  informed  has  also  In  evidence  were in  1971, p . 1 3 2 5 ) . consented  to the  p a t i e n t s have a  of a procedure. complications  "The will  (Alfidi,  against generalizing to this  to support  one  study,  but  t h e argument i n  consent. been  t o be i n f o r m e d  physician.  from  to  procedure  procedure  i s now outmoded"  (1980) c a u t i o n s  and  that  of p o s s i b l e  of the procedure  Barber  populations  suggests  the degree  complications  (Alfidi,  concluded  informing the patient  p. 1329).  other  1985).  heart disease.  this  and  know, and ' s h o u l d ' know t h e r i s k s  result  The s t u d y  of  from  desire  that  (Hoffman,  seriousness  procedure.  concern  However,  o f Canada, i s  (1971) e x a m i n e d  diagnostic to  Court  because  t r u t h f u l or  patient.  profession  the  i t s risks,  "straightforward 228  the  that  and p r e f e r e n c e s o f t h e p a t i e n t and  who c o u l d p o t e n t i a l l y  informed  Overall,  by  complex, o r t h a t  t h e Supreme  of the medical study  consent  p a t i e n t s r e f u s e d t o undergo a d i a g n o s t i c  (angiography) Patients  too  informed  frighten  by t h e w i s h e s  important  informed  is  will  Some p h y s i c i a n s a r g u e  of truly  according to  the standards An  1984).  i s o f t e n not capable  information  informed  (Grad,  a  produced  to  indicate  that p a t i e n t s  of ' a l l ' the information a v a i l a b l e to study  of  pregnant  women r e c e i v i n g a  12 diagnostic Berwick  procedure  et.al.  n o t want  (1985) f o u n d  t o know  surprise'.  (amniocentesis) to  the sex  Similarly,  (1976) f o u n d  that  important  withholding  to  none o f  summary,  the p a t i e n t ' s terms of those  treatment not  be  the  most  in  consent  must  must  effective.  is  medical  success  i s the o n l y r e l e v a n t  tions." 'ought'  basis,  The to  practise,  reason  As  "there  dominant  for  normative  matter t h e y do  for not  be  'be  a  Mcintosh to  However, i t  were  asked to the  to  of  a number  of  about treat-  of  life,  basis,  but  (1982,  that  of  just  in  quality  of  to  choose  a  choice that  p.  45)  has  the prospect f o r  or ought  reasons  seem t o be  not  allowed  Gorovitz  is  a knowledge  the a t t e n d i n g p h y s i c i a n ,  believe  argument  on  outcomes,  be  exercising  always  to d i e .  based  years)  stated:  the  i t to  i n t h e s t u d y wanted  relevance  treatment  the o p i n i o n  no  defects,  patients did  patients,  patients  little  Patients  may,  cancer  the p a t i e n t that  the  T h e y wanted  patients  additional  as w e l l .  of  birth  case.  preferences for  that  74  had  i n each  q u a n t i t y (or  years  the  here,  informed  half  the baby.  expected  note  needed  over  study of  information that  ment d e c i s i o n In  of  in a  know when t h e p h y s i c i a n is  that  identify  always  i n medical patient  to  be  situa-  preferences  ( B a r b e r , 1980).  In  given primary c o n s i d e r a -  tion.  1.4.  Attributes Medical  or  of M e d i c a l D e c i s i o n Making clinical  decision  m a k i n g has  b e e n d e f i n e d as  a  13 way  of  structuring patient  o u t c o m e s so  that  patient  guidance  of  a  benefits,  and  the  to  the  making  A medical three a  symptoms, and  the  of  three  health  the  prevention of  of  the  cost  of  that  ( i n c l u d i n g the  risk  of  the  The  value  the  law,  as  well  assessment which  death),  Third,  disciplines  "respond  minimum o f  speculation  and  tiny"  (White, Law  and  i n the  and  ethical  immediate, 1983,  p.  medicine  to  risks,  become c l e a r the  patient's  1979).  assessment  (utility)  of  including  relief  or  the  treatment is  a  determination  will  improve  c a u s e harm  that  the  the  interests  will  of  the  traditional  d e c i s i o n making has  been  circumstances with  human  problems  is  pragma-  t h e o r i z i n g , thereby maintaining concrete  the  1985).  tradition,  changing  the  to  treatment  physician's  (Evans,  from  reactions,  may  of m e d i c a l  British  Both  rootage  the  treatment  i n the  or  way,  the  of  treatment  treatment  under  result  second  the  component  improve  et.al.,  value  because of as  this  is generally  The  1977).  choice  to  patient  care.  In  occurring  adverse drug  the  shape  able  i s the  that  (Shapiro,  these  treatment  exercised  1976).  decision  the of  be  Weinstein  patient,  in diagnosis  tic.  for  probabilities:  physician  like  1968;  first  outcome  nothing  role  The  of  therefore  (or c l i n i c a l )  control  patient do  (Lusted,  components.  treatment  are  p r o b a b i l i t i e s of  can  (Pauker,  probabilities and  and  autonomy  physician  patient,  decision  values  under  a  a  firm scru-  73). have been grounded  p r i n c i p l e s , one  of  which  is  on  a  consensus  respect  for  of  moral  autonomy.  14 The in  Canadian  Charter  of  t h e r i g h t o f freedom  privacy,  making  processes  "The  to  decisions and  The  life  (Gorovitz,  second  some p r e d i c t i o n s decisions  is  predict  in  clinical the  probability likelihood used  based of  When r i s k  assumptions  the broader  of  medical  on e v i d e n c e  o f presumed  point  1978).  of view  perspective  may  of the  d e c i s i o n making The  other  (Arrow,  involves  purpose o f making events.  like 1965)  decision  t o be .  To able  However,  making  situa-  i s offer a prediction  i n terms o f a  of past  describes the  event.  events  that  Probability  i s t h e mechanism  risk.  i s defined can  likely  (Carlton,  one w o u l d  choices  many  c a n do  a  contribu-  will  and i m p r o v e o u t c o m e s o f f u t u r e  some f u t u r e  activities  values  values  1982, p . 4 6 ) .  m e d i c i n e , as i n  for quantifying  life's  from  and  In a d d i t i o n ,  medical  or r a t i o n a l choice,  one  issues  and d e a t h  purely  t h e outcomes o f t h o s e  best  of  o f outcomes o f a c t i o n s .  to a l t e r  r i g h t to  r h e t o r i c of i n d i v i d u a l  facts,  decisions.  a  component  make an i n t e l l i g e n t to  the  of l i f e  from  the  autonomy  and t h e r i g h t t o d e c i d e  The  questioning  n o t be t h e wrong d e c i s i o n  patient's  speech,  made by p a t i e n t ' s  i n matters  decision  formalizes  but t h e d e l i b e r a t i o n s of d e c i s i o n  clarify  make m e a n i n g f u l  wisdom  wrong  tions,  and  body.  cloudy,  aim to  exploration  physician  ...  sometimes  to c l i n i c a l  cause  beliefs  h a p p e n t o o n e ' s own  is  necessary tions  of  and F r e e d o m s  the r i g h t to s e l f - d e t e r m i n a t i o n ,  what w i l l rights  Rights  as a chance o f i n j u r y o r be  viewed  as  risky  l o s s , many o f  ( C h i l d r e s s , 1982;  15 MacCrimmon and refers loss. and  to  the  Wehrung, 1985) amount o f  'Risk-taking' voluntarily  conduct  that  There are decision correct signs  that  than  variables  paradigm"  1865  that  that  "mechanistic  that  relate  to  diagnostic  care. a  and  1977;  et.al.  incorporates and  alter  this  are these  first  and  and  patients of  causes  should  be  p.  to  course  in a  recognize  the  influenced  the  disease by  many  Hamm, 1 9 7 9 ) .  have  of  a  "probabilistic However,  expectations  described  by  Claud To  in  Bernard  in  change  a l . (1981) h a v e that  with  varying  effects.  gambles,  this  recommended  realize  as  they  grounded  should  viewed  to  227)4  Second,  of  uncertainties.  et.  "refers  evidence.  be  risks  p r o b a b i l i t y of  E x p e r i e n t i a l Medicine.5 Bursztajn  the  that  important  ability  the  may  are  the  proponents  patients  paradigm"  procedures  that  doctor's  Bursztajn  (1981)  i s aware o f  First,  'risk'  p r o b a b i l i t y of  ( C h i l d r e s s , 1982,  probabilities  on  certainty  number  actor  disclosure,  'Risk-imposition'  a treatment w i l l  doctors  the  interpret diagnostic  approach,  a  of  depends  i n P r i n c i p l e s of  first,  the  others."  health  doctors  mechanistic  is  in  (Shapiro,  Bursztajn  the  number  that  on  ordinary  l o s s and  them."  risk  symptoms and  less  suggest  a  diagnosis  probability is  assumes  making  or  possible  implies  imposes  "In  symptoms  not  may  Second,  as  methods  4 To g i v e a t r u l y informed consent i m p l i e s that the 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 risk-imposing.  patient  5 B e r n a r d s t a t e d t h a t s c i e n t i f i c laws a r e b a s e d on c e r t a i n t y , not probability. Scientific l a w s , and t h e laws o f m e d i c i n e a r e d e r i v e d f r o m t h e p r i n c i p l e s o f e x p e r i m e n t a t i o n and determinism i n s c i e n c e - a m e c h a n i s t i c approach.  16 for  determining  and  knowledge a r e  doctor's  cause. as  important  knowledge  acknowledged  that  symptoms  the  or  T h i r d , the  and  The of  this  third  underlying  This  understood  provide  treatment  feeling  of  omission  of  Finally,  disease  and  was  a patient's  been  the  health  it  as  the  should  be  elimination  treatment  can  of  actually  1974).  justified  by  the  outcome. by  were n o t  assuming  preferences  described  models of  preferences  treatment  guarantee  t h a t would maximize  have  discussion  of  cannot  (Illich,  a satisfactory  assumption  choice  component, p h y s i c i a n p r e f e r e n c e s ,  study.  physician  i n the  experience.  treatment  make a p a t i e n t w o r s e o f f  patient's values,  that  Evans  topic  that  he/she  patient's The  a  if a would  autonomy  weaknesses of (1984)  patient participation  and  in  and this  in  the  section  1.2  above.  1.5.  Uncertainty When  operates  the i n an  in C l i n i c a l physician  "unintentional  can  occur  I n any  every  treatment tion of  of  and  of  decision  and  outcomes  individual  initiate  makes a move there  Risk  treatment,  part  hazardous  of  of which  (Israel,  1982,  i s some u n c e r t a i n t y  treatment.  in c l i n i c a l  is  Uncertainty  causes of  disease,  the  d i f f e r e n c e s i n the  response  to  due that  p.  10).  about  is a  the  he/she  consequences"  medicine  u n c e r t a i n t i e s about:  disease,  a Component  uncertainty,  a l t e r n a t i v e modes o f  modes  to  potentially  time a doctor  therapeutic  outcomes of  elects  environment  to  Medicine:  the  about combinamechanism  treatment,  17 and  the dangers o f drugs There  in  is  medical  uncertain and  also  care  only  Doctors  for  five  steps:  the  patient,  of  choice,  on  patient  elicit  lives  fact,  from a p h y s i c i a n  patient's  understanding  1982).  Physicians  uncertainty,  and t h a t  state  patients  that  Doctors  strategy  that  is  express,  s t o r y not  If physicians  employ  about  the f o l l o w i n g  which try  (Katz,  seldom  t h e most  i s the best  to understand  practised.  Medical  factor  in a  treatment  (Gorovitz,  do n o t want  to discuss  cause  anxiety.  p o s s i b l y understand instead,  recommen-  1984).  influential  of a  patients  such d i s c u s s i o n s cannot  the  and make a t r e a t m e n t  and a c c e p t a n c e  state  of uncertainty i n  maximize t h e d e c i s i o n  i s n o t bound  i s often  judgements  w h e t h e r we a r e s i c k  preferences,  preferences,  this  i n these  available alternativesfor  uncertainties  the physician  of action  as w e l l .  would  the  patient  evidence  and t h e p a t i e n t .  they might  describe  combine  a course  T h e y may d i s t o r t  patient  diagnosis  generally  many a s p e c t s  i n a way t h a t  to  of a  weigh c o n f l i c t i n g  of our d a i l y  patients.  and  f o r those  t o which  problems.  of the  to ignore  the  admit  In a c t u a l advice  with  define  reasons  dation  tend  uncertainty  ability  treatment  tests,  the p a t i e n t , but f o r themselves  with  making  Physicians  the physician  i s a part  discussions  dealt  the  The r o l e  to both  Uncertainty or w e l l .  the accuracy  means t o make j u d g e m e n t s  1982).  may be u n c l e a r  about  1976).  from d i a g n o s t i c  use i n f o r m a l  their  uncertainty  (Elstein,  data  (Gorovitz,  to individuals.  certainty  They  complex about  also  medical  treatment  18 choice  (based  socialized, tient  1.6.  on  Representing has  expressed  Raiffa,  when t h e y  tion.  For  parents  defined  the  the  the  Katz,  their  doctor-pa1984).  chance of  probability  deformed  based  number o f p a r e n t s  and on  (1981) can  of  to  use  choosing  informa-  indicated  the  birth  an  1982;  probabil-  differentiate and  is  Patients  diagnostic  giving  which  (Childress,  have  child  probability  loss,  Wehrung, 1 9 8 5 ) .  to understand  et.al.  a  that  the  risks  risk  of  an  to a  deformed  elective  abortion  rose. Throughout  single  number  ambiguity.  this  study,  Ambiguity, where t h e  described  by  in  this  outcomes  a range  of  i f s u b j e c t s were o f f e r e d  with  an  outcome d e s c r i b e d with  range),  most  an  so  as  an  ambiguous  can  action  outcome  of  be  (or  Ellsberg  a c h o i c e between  i n terms  subjects w i l l  are  to avoid  context,  of p r o b a b i l i t i e s .  that  one  probabilities  wherever p o s s i b l e  situation  and  a  preferences  bearing a  When  rose,  the  genetic counselling  with  p a r t of  D e c i s i o n Making  MacCrimmon and  Pauker  as  p a t i e n t s and  S t o e k l e , 1972;  as by  the a b i l i t y  example,  abortion.  making  1976;  philosophy)  views about  in Medical  indicate  seeking  associated  infant  Risk  been  have d e m o n s t r a t e d  treatment  ( W a i t z k i n and  in decision  Keeny and  ities  rigid  paternalistic  relationship  Risk  also  a  risk  two  former  the  as  problem  of  d e s c r i b e d as treatment) (1964) gambles  a  a  are  showed -  one  (a p r e c i s e outcome)  (the p r o b a b i l i t y  p r e f e r the  expressed  even  i s given  as  a  i f the  proba-  19 bilities  are  ambiguity  avoidance.  health  care  ambiguity  response t o  there reduce  gives  called  behaviour  making s i t u a t i o n s i n  be w i l l i n g  important  in  t o pay t o a v o i d  understanding  s i t u a t i o n i n medical rise  The  this  such  1985).  to  the p r o b a b i l i t y  the r i s k .  (1961)  in decision  shown t o  are  the risk  that  is  Subjects  et.al.,  factors  event  Ellsberg  have been  (Curley  Two  the  similar.  the  that  a  second  care.  potential treatment  probability  a  First,  risk,  patient's there i s  and, second  or i n t e r v e n t i o n is  often  will  called  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 making: o b j e c t i v e defined an  in  receiving  probability  previous symptoms  and  likelihood  the  the  may be  patient's  understanding  test  of  this  of  the  the  made  objective  objective  combining  information  context  necessary  or c a p a c i t y  the  of  outcomes  from s i m i l a r  physician  from t h e p a t i e n t ' s  i t i s usually  ability  a  data  The c a l c u l a t i o n o f  cases with  in  derived  by  results  treatment  assessment  terms,  made  similar  probability  physician's  practical  on e p i d e m i o l o g i c a l  usually  about  of various  measure  decision  probability i s often  s p e c i f i e d treatments.  diagnostic  Subjective  This  is  knowledge  Objective  i n medical  d e c i s i o n m a k i n g a s a p r o b a b i l i t y j u d g e m e n t by  I t may be b a s e d  populations this  and s u b j e c t i v e .  medical  expert.  of p r o b a b i l i t y a r e used  new  patient.  i s defined by  on t h e  as t h e  the p a t i e n t .  understanding of probability.  In  t o make an e v a l u a t i o n o f  t o a c h i e v e an a d e q u a t e probabilities  of  l e v e l of treatment  20 outcomes  (Gorovitz,  1982) .  Two f u n d a m e n t a l p e r s p e c t i v e s been e x p r e s s e d . objective oriented p.  82)  ing:  Savage  probabilities, and t h e r e  has  "In  estimate cies)." asserting  (1954)  is  no r e c o r d  Edwards that  established  In  this  studies treatment (Pauker, The risky  an  (based  on  decisions  of  medical  outcomes  (1982,  by s t a t -  relative  side  to  frequen-  o f t h e argument,  can e a s i l y  be compared  future  updates  events.  objective  a l l previous  cases.  In  d e c i s i o n making, e p i d e m i o l o g i c a l  records  of  are  treated  as  objective  probabilities  1976). attitude  of a p a t i e n t  i s a function  about  his/her  (1972)  has  probabilities  and  of  of  stated  found  toward  that  (a this  subjects  underestimated  judgements  First,  risk that  r i s k - t a k i n g or accepting  three  situation.  of the l e v e l  because h i s study  high  risky situation.  Third,  must  make  subjective probability). appraisal  overestimated ones.  the patient  a  the p a t i e n t  the patient  must h a v e some i n t e r n a l m e a s u r e o f t h e a n x i e t y the  Israel  impossible  involving  from  a r e no  are future  argument  virtually  the other  probabilities collected  appraisal  Tversky  Savage's  is  there  events.  probabilities  by  that  way, t h e outcome o f an i n d i v i d u a l c a s e  treatment  must make  i t  p r o b a b i l i t i e s have  a l l decisions  o f such  (1962) h a s t a k e n  p r o b a b i l i t i e s revealed  (outcome)  that  probabilities  to  stated  supported  circumstances  objective  has  arguing  conditionally  some  of o b j e c t i v e  may be  biased  low o b j e c t i v e  Second,  the patient  caused  by b e i n g i n  must make an e s t i m a t e o f  21 the is  e f f e c t of t h e r e m e d i a l made d i f f i c u l t  treatment  outcomes  treatment p.  the  whether  ities  are  the is  this  comparison  dominance  the  of  patient,  estimate,  of  Israel  because:  i s evolving  estimation vectors  some a s p e c t s  psychological  the disease  cannot  et.al.  variables  to  physician  the  tell  trade-off tions.  strate  subjective  of a s t a t i s t i c a l  the patient angina  between  state  into  variables  p o s i t i o n to  pain  These p a t i e n t  one  (1981) have s t a t e d  health  is in a  chance of reduced  of  necessary  considering  translated  health  tables)  of  (Mooney, 1 9 7 7 ) . T h i s  of  of the  states  (1982,  "..no two m e d i c a l  differences  at the  r a p i d l y or s l o w l y ,  and  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 . " Bursztajn  the  It  must make  are alike,  outset,  the and  process.  82) who  cases  by  action  of  and  response expects  risk  patient.  While the  describe  the  objective  risks,  risk  different  the r i s k  another.  for values  dealing to  with  with  life  the r e l a t i v e Patients with  be a t t a c h e d  restric-  importance  may a l s o  demon-  similar levels  the r i s k , risk.  a  determines the  or other  associated  he  of death against  preference  of death  due t o i n e x p e r i e n c e  mechanisms  (using a c t u a r i a l  the  d i f f e r e n t l e v e l s of a n x i e t y  objective  population  Patient  over  probabil-  p r o b a b i l i t i e s by c o m p a r i n g  judgements d e t e r m i n e  health  objective  of  how t o w e i g h pain.  that  or d i f f e r e n t  Therefore,  t o t h e same  one  treatment  outcome by d i f f e r e n t p a t i e n t s . For be  used  example,  i f patients  a s an a p p r o x i m a t i o n  state  their  life  of the s u b j e c t i v e  expectancy, risk  patients  i t can apply  22 to  the  will  seriousness  kill  be  a  patient  calculated  (objective)  (Edwards,  due  their  population A done  Knetsch  and  subjects  1962).  patients  a study  feelings stated  c h a n c e of  than  in  in d e t a i l  the  risk  Isen  risk-taking  some  population  problems  and  not  the  risk.  the  Patrick  dilemma was  reported  with  real  (Isen  and  of  cancer  diagnostic  1985).  risk  (1983) u s e d  effected  when  Patrick,  behavioural  s i t u a t i o n that  on  These  3.  resources.  bravado  1979;  done  for  (job change).  less  been  Studies  p o s i t i v e f e e l i n g s on  and  have  Tversky,  Weinstein,  i n Chapter  three  behaviour  women r e c e i v i n g  and  risk  actually losing"  a  the  from a c t u a r i a l  present  been  and  " e x h i b i t more  (1976) n o t e d  ratio  and  Some h a v e b e e n  as  have  e f f e c t of  taking  a  estimate  (Kahneman and  bets  1978)  a hypothetical  people  Jones-Lee people  of  subjective  expectancy,  drawn  taking  1980).  (Berwick  hypothetical  that  general  risk  risk  defects  subjects,  and  that  on  money  to  patient  the  it  risk.  et.al.,  reviewed  among s t u d e n t  found  1984;  limited  birth  (roulette)  the  Thaler,  tests  In  at  life  tables  Sinden,  (McNeil  are  Actuarial  p r o b a b i l i t y that  expectancy  the  situations  patients  studies  of  the  determine  his/her  hypothetical  responses  for  on  of  and  roughly  patient's  experiments  using  patient's  the  expectancy  number of with  To  representation  of  disease  places  from  life  tables to  their  them p r e m a t u r e l y .  probability can  of  are  In  real The  by  p.  risk  authors subject's  addition,  there 1983,  taking  is  they  little  200).  c h a r a c t e r i s t i c s of of  importance  to  the  23 present not  study  bankrupt  complete  to  Third,  risk  will  be  zero.  assumes  that  present  wealth  useful  to  (1971) c o n s i s t s financial,  and  voluntarily  and  risks  that  that  are  radiation  can  be  h a v e an  basic  of  that  to  a patient  risk,  which Mishan  risk  is  reduced  Jones-Lee  (1974)  of death  risk  to a  some o f h i s  without  risk,  the  are  study  drawn f r o m  those people  care  as  born  involuntary  to  This risk  i s the o n l y approach  assume  Direct-  such  risk  someone's  experienced  individual.  Mishan  demand f o r  A financial  due  has  a  a conscious decision,  infections.  i t is  direct-involuntary,  factor.  of a r e d u c t i o n i n the feels  larger  of a r e d u c t i o n i n  measuring  risks  risks  i s the sadness  a cherished  a  situation  to take a  the  types: d i r e c t ,  is  than  compensation  forfeit  of  of e l i g i b l e  inherent risk  (or g a i n )  value  on  described in health  induced  psychic risk  would  types  Direct  or  while a  as  will  probability.  the  bear  loss  amount o f  probability  section  those people hospital  low  other  is in a  argument,  person  low  A list  psychic.  monetary  disability  the this  of four  a  a patient  risk  the p a t i e n t  this  this  briefly  to measure.  no  increasing  prefers  concluding  in  v a l u e to the p a t i e n t and  to a t t a i n  identify  attempted  services  and  First,  the p a t i e n t  induce  presenting  a person  Before  to  positive  probability,  if  increasing,  able  In  reduction  Second,  the marginal  be  toward  high  any  is potentially  likely  risk.  disease patients.  himself for  reduction.  where r i s k is  of h e a r t  is a  death,  at the death  s t u d y measured of d e a t h , that  a  as  or the  direct  makes s e n s e  in  24 theoretical  terms.  Direct-involuntary  objective  probabilities  following  section  of treatment  publicly for  risk  i s not  supported,  treatment  than  1.6.  outcomes  described  measure f i n a n c i a l  an i s s u e  i nthe However,  or psychic  i n C a n a d a , where h e a l t h  and p s y c h i c r i s k  i nthe  risk.  care i s  was an i n a p p r o p r i a t e m e a s u r e  patients  made  f o r themselves,  rather  else.  Summary The  through  present a  consent.  study of p a t i e n t  discussion  protection  of p a t i e n t Evidence  inherent  i n treatment,  ing process The  i n medical  following  epidemiology, coronary terms  in  their  treatment  attributable Canada.  This  alternatives  of the reasons autonomy  f o r greater attention  and  of treatment  the  care  section  (Hiatt, is  criteria  on t h e u s e o f p r o b a b i l i t i e s  factors  devoted  i n the decision-mak-  and  a  costs  discussion of  It  historical  context, a description  to  coronary  information available  includes:  to  disease.  and  forms  other the  for patients  on  types basis  of the  treatment  definitions  information  and  f o r informed  1975).  options  protocols,  to the  o u t c o m e s and t h e u n c e r t a i n t i e s  two i m p o r t a n t  treatment  heart  p r e f e r e n c e s has been i n t r o d u c e d  has been p r e s e n t e d  to d e s c r i b e the r i s k s  and  to  choices the  f o r someone  are reflected  on c o r o n a r y h e a r t d i s e a s e i n C a n a d a .  the study d i d not attempt Financial  risks  of  of medical  o f t h e symptoms  the  h o s p i t a l use  of heart disease i n for  the treatment  and t h e o b j e c t i v e  probabili-  25 ties  that  which  are  medical  describe used  the  risks  in concert  associated  with  patient  The  Clinical  The  heart in  the  pain  chest  pectoris. sensation  He  or  of  make a  angina  radiating  by  or  Royal  College  of  Heberden d e l i v e r e d a paper  on  at  "a  as  word  with  if  the  exertion  relieved  by  is a tight  or  squeezing  c e n t r a l chest  Severe  left  narrowing  death  or  arm, of  shoulder, the  damage t o  the  rest.  or  coronary heart  to  a r i s e s when  due  to  of  the  inadequate heart.  i n persons with  be  the  p.8).  w h i c h means  Angina  arteries  extinguish  1985,  'angere'  angina  disagreeable  i t would  supplied  the  heart:  most  (Grotto,  1981).  oxygen of  of  p a i n f u l and  continue"  narrowing  the  disease  Greek  the  Disease  may  to  and  as:  Economics  of  (Shillingford,  frequently  disease  cause of  to  understanding  w h i c h seems  the  exceeds  caused  with  and  clinical  1772  William  increase  from  demand  more  in  it  breast,  suffocate  circulation  began  described  i n the  Epidemiology,  current  associated  comes  strangle  our  London when  i f i t were t o  'Angina'  heart  of  disease  Physicians  occurs  preferences  H i s t o r y of C o r o n a r y H e a r t  history  coronary  oxygen  treatments,  TWO  CORONARY HEART D I S E A S E : H i s t o r y ,  life  the  decision.  SECTION  2.0  with  A classical pain,  It  coronary symptom  frequently  neck. vessels  is generally  m u s c l e known as  the  'myocardial  26 infarction'.  Narrowing  A myocardial tion  of  infarction  a clot  on  present.  Pain  infarction,  and  ischemia' In angina  arteries. of  the  It  was  the  correct  and  in  Scarpa's  always  the  of  elasticity The  term  sclerosis another  of  of  fatty  atheroma) which  the  forma-  can  a  is  myocardial  occur  as  'silent  that  the named  that or  defined  the  process  inner  cause  studies. described  Scarpa  t o o k many y e a r s .  the  by  term  artery  of was  In  1883  Jean-Fred-  now  covers  walls  to  a  lose  harden.  lining  Marchand,  deposits  lining.  generic  areas  a condition  'arteriosclerosis', This  coronary  diseased  Scarpa  as  arterial  the  autopsy  Antonio  vessels  of  the  during  that  coronary of  r e l a t i o n s h i p between  'atherosclerosis', describing  pathologist, of  the  atheroma'  a pathologist.  the  to  with  cause: disease  century  the  thicken  due  'stenosis'.  a r t e r y where s t e n o s i s  muscle  anatomically  next  conditions and  heart  discovered  'coronary  d e s c r i p t i o n was  variety  be  associated  underlying  Jenner  thinking  to  a  1985).  Jenner  the  i s termed  a coronary  the  degeneration  Lobstein,  thick.  not  1793  until  ulceration  result  is  and  pathogenesis  erick  of  a r t e r i e s as not  believed  wall  Edward  In  vessels  the  damage t o  pectoris  the  i s now  (Shea e t . a l . ,  1778  of  called  cause the  of in  the 1904.  artery,  lining  kind was  of  arteriocoined  Atherosclerosis  'atheromata'  artery  the  to  is  (from Jenner's become i r r e g u l a r  by the  term and  27 In  1912  published  the  Journal  "Clinical  Coronary A r t e r i e s "  to describe  can  cause  the chest  (Grotto,  attack)  believed  to  Some o f  obesity,  sedentary  acknowledged  hypertension.  2.1  Grading  thickening sclerosis  its  of  these  call  causes  article,  of the  angina, sudden  blood  and s o m e t i m e s the  factors  living,  of  coronary  death  the  Herrick i s arteries  and m y o c a r d i a l  infarc-  in  some  persons  interrelated  risk  factors  heart  no p a i n  stress.  chronic  disease  is  to the heart  Angina,  capaciaty,  is  or angina  pectoris,  common  symptoms  of  coronary  include  shortness  of breath  may is  heart  is  a l s o an  as  diabetes  Disease by  atherosclerosis: a This  not always  i s adequate  i s associated  angina pain  such  of the a r t e r i e s .  of the heart  heart  r e l a t e d : smoking,  conditions  caused  lining  coronary  Heredity  with  athero-  symptomatic.  to maintain  the  However, when t h e o c c l u s i o n c l o s e s  initial  of  are l i f e - s t y l e  of Coronary Heart  the i n t e r i o r  supply  development  and  as a r e  of the v e s s e l s  oxygen,  vessels.  that  the Angina  Coronary  cient  p a i n we  Association  Obstruction  In t h i s  obstruction  influence  factor  and  the  how  o f complex  disease.  If  Sudden  Medical  1985).  A number are  of  by James H e r r i c k .  first  (heart  the American  Features  the  tion  of  narrowing  suffiof the  t h e v e s s e l t o 30% o f  occur. only  one  disease.  and f a t i g u e .  Angina  of  a  number o f  Other can  symptoms be  classi-  28 fied  by  a  number  of  systems.  The  grades  listed  i n Table  established  by  the  Canadian C a r d i o v a s c u l a r  Society  recognized  by  the  American  and  TABLE  National  Heart  1.1  were  (1972) and  Lung  are  Institute.  1.1  Grading  of  Angina  of  Effort  by  the  Canadian  Cardiovascular  Society 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 d o e s n o t c a u s e ... a n g i n a " , s u c h as w a l k i n g or c l i m b i n g s t a i r s . Angina with strenuous or r a p i d o r p r o l o n g e d e x e r t i o n a t work o r 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 . " W a l k i n g or c l i m b i n g stairs r a p i d l y , walking uphill, walking or s t a i r c l i m b i n g a f t e r m e a l s , or i n cold, or in wind, or under emotional s t r e s s , or o n l y d u r i n g t h e few h o u r s a f t e r a w a k e n i n g . Walking more t h a n two b l o c k s on t h e l e v e l and c l i m b i n g more t h a n one flight of ordinary stairs at a normal p a c e and i n n o r m a l conditions. 3.  "Marked l i m i t a t i o n o f o r d i n a r y p h y s i c a l a c t i v i t y . " W a l k i n g one t o two b l o c k s on t h e l e v e l and c l i m b i n g one f l i g h t o f s t a i r s i n n o r m a l c o n d i t i o n s and a t a n o r m a l p a c e .  4. " I n a b i l i t y t o c a r r y on any f o r t - a n g i n a l syndrome 'may' SOURCE: C a n a d i a n p. 522)  2.2.  The  Medical  Epidemiology  Coronary heart Canada and affects  the  Association Journal  of  Coronary Heart  disease  United  physical activity without be p r e s e n t a t r e s t . "  is  States.  p r i m a r i l y o l d e r age  the It  groups  (1975,  vol.122,  Disease  leading  cause  is a progressive and  discom-  of  death  disease  frequently affects  the  in  that  29 middle aged. In all  t h e sudden  of  cancer.  appears is  deaths  countries,  and f o r t w i c e  Although  the  i t accounts  f o r about  as  many d e a t h s  incidence  of coronary  t o be on t h e d e c l i n e i n C a n a d a a n d t h e  one  of  the  (Shillingford, 1982,  Western  this  28,796  1981).  type  men  major  causes  Statistics  of heart  and  of death  disease  20,239 women  as a l l f o r m s heart  United  disease  States, i t  i n the twentieth  Canada  reports  was  the  80% o f  century  that f o r  cause  of  ( S t a t i s t i c s Canada,  death f o r  report  84-203,  1984) . Statistics the  number  length  the  for  were  Canadian  s e l e c t e d and  International  importance  country.  Four  Table death, acute  the  myocardial  hospital  of  heart  disease.  diagnosis  of angina  18,000 of  death.  disease women  a r e summarized of  for  associated ranges  1973).  In  for  heart  but t h i s  from  to  will  tend i t  (using  indicate the  disease  the Canadian i n summary  in this Classiform i n  made due t o  a hospital  combining  to overstate  stay f o r  mortality  i s seldom  data  the incidence  i s u s e f u l t o note  u t i l i z a t i o n of h o s p i t a l diagnosis  1.2  Five  20% t o 30% o f p a t i e n t s i n  As a r e s u l t ,  addition,  causes  with  1978.  i n Table  Disease)  identify  and t h e a v e r a g e  do n o t i n d i c a t e s e p a r a t i o n s  separation data  patients,  diagnosis  f o r 1982 and a r e p r e s e n t e d  infarction  and  by  were s e l e c t e d f r o m  mortality  (Acton,  and  treatment  H o s p i t a l data  but  hospital  of  diagnoses  of Disease  1.3.  men  Classification  economic  fication  separations  of patients treated f o r heart  of stay  diagnoses  on h o s p i t a l  care  that the by a b o u t  l i s t e d as a c a u s e  30  TABLE  1.2  Hospital per  100,000  (using  ICDA 410  411  412  413 427  Stays  f o r Canadians with  Population,  Heart  1978  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  DIAGNOSIS  MEN  acute myocardial infarction o t h e r forms of ischemic7 heart disease chronic disease  Disease,  (no.)  of  DAYS6  Disease)  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  are l i s t e d , only illustration.  five  heart  angina symptomatic heart disease  NOTE: Many other diagnoses i n c l u d e d i n t h e t a b l e as an SOURCE: S t a t i s t i c s  6 Days r e f e r s  Canada  (1984, B u l l e t i n  to the average stay  7 Ischemia means damage inadequate oxygen supply due arteries.  categories are  84-203, p . 87-89)  i n days p e r p a t i e n t .  to the heart muscle c a u s e d by to c o n s t r i c t i o n of the coronary  31  TABLE  1.3  Hospital per  Stays  100,000  f o r Canadians with  Population,  the Canadian C l a s s i f i c a t i o n  CCL  DIAGNOSIS  MEN  082  hypertensive disease  084  086  Disease,  1980-1981  (using  083  Heart  of  (no.)  Disease)  DAYS  WOMEN  (no.)  DAYS  7,670  14.4  11,771  15.4  acute myocardial infarction  32,983  15.1  15,680  20.4  o t h e r forms of ischemic heart disease  55,816  12.7  36,137  22.5  o t h e r forms of h e a r t disease  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 f r o m T a b l e 1.2, m a k i n g c o m p a r i son by y e a r s impossible. Where the diagnoses are consistent, numbers o f c a s e s p e r 100,000 p o p u l a t i o n a r e s i m i l a r . SOURCE: S t a t i s t i c s  2.3  Canada, M o r b i d i t y  The P r o g r e s s i v e  of  disease  i n most p a t i e n t s  the  prognostic  d i s e a s e , M o i s e and determined  that  (1984, p . 122-123)  Nature of Coronary A r t e r y  Coronary a r t e r y disease  Report  is  (Moise  considered  139  had  to  and B o u r a s s a ,  significance Bourassa  Disease  (1985)  of  be a  1985) . I n  progression examined  progression  of  progressive  313  of  a  study  coronary  p a t i e n t s and  the disease,  33 d i e d  32 during  the  infarction serious  study but  (or  period,  survived.  sive  disease  year  73%  stated  year  of  artery  disease.  with  patients the  with  rate  segments o f status  of  this  the  the  studied  with  also  patient,  the and  the  For  a myocardial  for  89%  was data  infarction,  the  disease  artery disease identified  Factors  the  it  When  progression  were: the  the  83%.8 of  previously  initial  while  non-progressive  i t was  four  infarction  disease.  progression  of  progres-  example,  arteries.  age  of  disease.  was  more  period.  reduced  identified  progression  artery,  study  had  significantly  disease  found  myocardial  patients  myocardial  years  acute  combination  disease  a  normal c o r o n a r y  of  the  the  the  an  (63%)  progressive  without  They  of  that  with  surviving four  patients  end  infarction  while with progressive  31  211  non-progressive  M o i s e e t . a l . (1985) 16  suffered  s u r v i v a l with  patients  of  the  patients  patients  probability 94%  with  39  total,  at  myocardial  four  for  included  also  of  of  patients  only  was  and  survival  probability for  In  f a t a l ) disease  These authors  and  i n 3 of  of  patient,  cholesterol  minimal  associated  number  the  in  20  with  diseased smoking  level.  8 The G o m p e r t z e f f e c t i s an i m p o r t a n t c o n t r i b u t i n g f a c t o r i n the mortality rates stated for persons with coronary heart disease because this specific population is an ageing one. G o m p e r t z (1825) showed t h a t a f t e r a c e r t a i n age t h e l i k e l i h o o d o f dying is more a function of age t h a n d i s e a s e ; a g e i n g 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 In  Clinical the  following  coronary  heart  because  it  a  key  is  one  Angina  it  stress.  In  therapy The  s u c h as  coronary  heart, that  thus  supply  areas  itself  which  heart  and  i t s vessels.  heart  second  r a t e and  sympathetic with  angina  the  the  nerve  by  were t h e most  this  group  Canada  i n 1970  but  was  of  1985).  disease  goal and  for  it  activities  modification, three  was  nitrate  common.  group,  The blood  treated  reducing  reduces  supply  s t r e t c h i n g of  beta-blockers,  act  c o n t r a c t i o n by to  the  improvements  with  i s propanolol widely  heart  used  to  which act to  to the  arteries volume the  in  heart  regulate  blocking  muscle.  and  drugs.  of  nitrates  blood  heart  that  medical  groups of  the  drugs,  not  common  normal  demonstrate s i g n i f i c a n t  used  symptom treatment  Nitrates also dilate  transmission  widely  of  for  phgysical activity  i n c r e a s e the  f o r c e of muscle  are  a  reducing  o r more o f  in turn  group of  a major  signs  heart  lifestyle  and  than  t o l e r a n c e when t h e y  (Myers,  use  pain.  treatments  study.  some  arteries  other  the  The  is  reducing  is  smoking, o v e r e a t i n g ,  in general  relax  pain  managed  to  as  important  chest  i n v o l v e s one  trinitrate  angina  for coronary  be  addition  drugs  of  alternative  i s on  most  present  often  glyceryl the  the  Therapy  on  focus  treatment  generally  first  of  i n the  can  aggravate  the  Control  seeking  symptom  sections  disease,  effectiveness. patients  Background: Medical  the  Patients  in exercise  beta-blockers.  The  most  w h i c h became a v a i l a b l e i n until  five  years  later  34 The calcium  third channel  including the in  group  of heart  conjunction Few  blockers)  relaxing  force  studies  have  sizes  the  side  personality management the  heart  survival patients  effects  can  small  sample  (Myers,  1985).  about  70% o f  for  treatment  are troubled  as d r o w s i n e s s ,  so p a t i e n t  impotence,  compliance  of the blocked  t h e 30%  studies  small  Some p a t i e n t s  such  o r who  Those  have used  angina  disease.  from,  alone or  the e f f i c a c y of these  differences  relieve  Surgical  decreasing  be u s e d  i n combination.  of the drugs  relief  T h e y may  actions  can  be a  vessels i n  of p a t i e n t s  who  a r e not compliant  do n o t  with  drug  ( S h e l l i n g f o r d , 1981). e t . a l . (1984) have s t a t e d  with rate are  coronary than  heart  surgical  treated  that  disease  treatment  medically.  These  f o r s e l e c t i o n of n o n - s u r g i c a l  physician  surgical  detect  cardiac  called  and/or n i t r a t e s .  or  c h a n g e s and n a u s e a ,  pain  ..."reasons and  cannot  (also  a r t e r i e s and  t o compare  i s an a l t e r n a t i v e f o r  Califf patients  coronary  compare o u t c o m e s  coronary heart  problem.  experience treatment  to  several  contraction.  e i t h e r alone  antagonists  have  beta-blockers  treatment  with  calcium  which  are available  and t h e r f o r e  patients by  muscle  attempted  Medical  the  (dilating)  with  groups of drugs, that  is  risk"  preference, (Califf  concomitant  et.al.,  may  medical  demonstrate a  because authors therapy illness,  1984, p . 1 4 9 4 ) .  therapy f o r  more  lower  high  risk  reported  that  include  patient  and e s t i m a t e d  35 2.5.  The C l i n i c a l Coronary  Background: Coronary  Artery  interposition  Bypass  of a vein The  patient's  During  legs.  temperature maintained and  the  less  is  than  around  venous  CABG  coronary  is  the  i s arrested  i s usually  takes  heart  b l o c k e d by  taken  from  the  patient's  body  and c i r c u l a t i o n i s  the place of the heart  available  good  the s u r g i c a l  arteries  procedure  pump t h a t  70 y e a r s o l d w i t h  (CABG)  are  the heart  by a m e c h a n i c a l  Surgery  homografts  this  reduced,  lungs.  Grafting  graft  atherosclerosis.  Bypass  t o low r i s k  function  patients  and  no o t h e r  adverse d i s e a s e s . About improved Surgical alter  80%  angina  to  90%  status  treatment  of  patients  (Pauker,  of  1976;  angina  does  the course of a t h e r o s c l e r o s i s  whether  i t  alters  (Hamilton e t . a l . , artery  stenosis,  patients  who  survival  of  the  subsequent  1983).  In  studies  h a v e had CABG  demonstrated  patients in  the  have  shown  European  of  to s i g n i f i c a n t l y  there  a g r e e m e n t on  left  infarction  main  prolonged  Coronary  coronary  survival  e t . a l . , 1983). vessel  have  a l . , 1984).  of myocardial  case  triple  is  a graft  et.  not appear  risk  (Alderman,  receive  Reeder  nor  the  with  who  Increased  disease  Surgery  in  has  Study  been Group  (1980) . A major was c o m p l e t e d reported tional  that:  medical  clinical i n 1983. "bypass  trial  of coronary  The C o r o n a r y surgery  management  in  Artery  artery  bypass  Surgery  Study  i s no more e f f e c t i v e  prolonging survival  grafting  than  among  (CASS) conven-  patients  36 with  stable  1984,  p.8)  ischemic heart disease." This study  and  Blood  who  demonstrated  study  Institute)  found  mortality 1975 of  to  age  1978 rose  patients  across  to  third,  6.4%;  the m o r t a l i t y  death  second,  the f i v e curves  year  with  the  The  CASS s t u d y  for  586  men  not  h a v e CABG.  survived  10  who  E i g h t y per  y e a r s ; and  Braunwald selected four. ting  change  CABG  However, t h e on  patients whom  for  less in this  have  43%  (1984) has  had  in  latter  in surgical  criteria,  from  and  0.3%  almost  experience related  of  fourth,  g r o u p s were  t o be  years  to  of  lower  of  survival did  of p a t i e n t s s u r v i v e d 5 y e a r s ;  61%  1970's  myocardial  70  from  but  concluded  group  89%;  baseline rates  s u r v i v e d 15  cases.  surgical  mortality  ranged  Increased  a myocardial  years  that  had  trend f o r the  severe  a  the  medical  The  1976).  from cent  surgery  seemed  Lung,  CASS s t u d y  month  r a t e was  1984).  determined  recovered  i n the  the  three  technique  also  first,  the  and  27,  arteries.  f o r p a t i e n t s over  survival  r a t e s of p a t i e n t s (Pauker,  Heart,  rate  for surgical  (Braunwald,.  teams  facts:  performing  Nov.  f o r 25,000 p a t i e n t s  o r more c o r o n a r y  the  institutions  Post,  National  a registry  significant  while  7.9%;  superimposable surgical  2.3%  Medical  the  6630 p a t i e n t s f o l l o w e d  was to  o f one  following  of  by  established  blockage  the  rate  (sponsored  (The  a  angina  of  50,  infarction. outcome  data  grades  been  addition,  i s about  (Braunwald, majority  1980's has In  infarction  1984).  of  cases  three  toward  the average  approximately As  a result  from  the  and  operaage  of  half  of  of  this  1970's i s  37 difficult  t o compare t o t h a t  Some c o n t r o v e r s y o v e r grafting  has  studies  demonstrating  treatment  emerged  over  Frick  in  of  the  the medical either  the medical  one  36  67%  of  treated  surgically  reported  trial  of  Study  of  medical This  study  little vors  plus  in  either  infarction In studies,  of  study  of  disease.  a In  with  similar  follow-up  treated patients  heart disease. of  surgical advantage.  a five-year  surgically  term  were m e d i c a l l y  patients  After  long  the  artery  pectoris  42  occlusion  similar  Fewer m e d i c a l l y  a major  that  methodology,  results Veterans  of  vessel  than  left  a randomized  therapy  for patients  over  et. a l . controlled  were compared  with  a five-year  ventricular  A number  Detre  Administration Cooperative  of medical  therapy  group.  stable  angina.  p e r i o d , therapy  function  among  of p a t i e n t s d i e d of  to  had  survi-  myocardial  study.  to the  controversy  the.  their  effects  resting  d u r i n g the  addition  of  the  determined on  coronary  group  follow-up  surgical  effect  with  angina  69%  study with  The  of  bypass  patients.  p a t i e n t s from CABG.  with  prospective  stable  complete  treated  another  (1984)  and  advantage  treated.  p r o g r e s s i o n of  p a t i e n t s had  In  other  surgically  the medical  demonstrated  did  p a t i e n t s with  were  literature,  a  of p a t i e n t s  symptoms  coronary  conducted  series  the  of  or o n l y a s l i g h t  randomized  while  no  merits  treatment,  (1983)  treated  1980's.  relative  et. a l  group,  the  c o n t r o v e r s y over  exists  over  the  the  problems  findings c r e a t e d by  of  these  random-  38 ized  clinical  studies data  are fraught  by  from  Rahimtoola  with  the sponsoring  the  initial  hypothesis, cant  trials.  crossover  problems  of  stated that  including: possession  i n d u s t r y , drawing  hypothesis,  exclusion  (1985) h a s  t h e wrong  continuous  patients,  and  of the  conclusions  alteration  o f many o f t h e e l i g i b l e sample  of  patients,  sizes  these  too  the  signifismall f o r  comparison.  2.6.  The C l i n i c a l A more r e c e n t  disease  innovation  Angioplasty i n the treatment  i s Percutaneous Transluminal  (PTCA).  Coronary  reducing  the  equipped  balloon.  The  coronary  angioplasty  stenosis  catheter  plaque  Background:  with  balloon  artery  to  in a  a  a  wire  or  The c a t h e t e r  artery using and  inside  compress route  used  artery  Angioplasty  non-surgical  coronary  inflated  dislodge  i n the v e s s e l .  is  guide  is  Coronary  of coronary  a  small  method a  of  dilating  inflatable  a partially  blocked  the a t h e r o s c l e r o t i c i s usually  ( t h e a r t e r y i n t h e p a t i e n t ' s l e g ) b u t may a l s o be  femoral  brachial  (from  the arm). During will  be c o m p l e t e l y  myocardial is  inflation blocked  infarction.  always a p o s s i b i l i t y  controlled the  the  injury  of  the b a l l o o n , the coronary  which  may  cause  severe  artery  angina  or  S u r g i c a l i n t e r v e n t i o n i n t h e f o r m o f CABG for patients  to the  coronary  who  elect  vessel heals  p a t i e n t can u s u a l l y r e t u r n t o normal a c t i v i t y  a n g i o p l a s t y . The slowly,  although  w i t h i n a week.  39 There are required  a number for  PTCA  to  work.  returning Amiel  et.al.  previously  treated  treatment  is  decreased In success bypass  including  (1984) by  CABG  surgery  as  was  6 deteriorated a  using  rate  631  patients. a five  reporting  to o c c u l s i o n  a mortality dence of  to  with  of  the  10%  of  patient  patients  angioplasty.  i f the  rate  from  year on  of  the  of  complications  angina)  12%  of  2 died  found  The  stenosis  Lung and  patients  is  report  from the  1.1%  patients.  that  due  study  a  due  method  coronary  This 25  had et.  to  caused  followed  33  The  study,  rate  of  failure  of  34 59%  a l . , 1981).  failed  rate  (less  a l . , 1979).  The  angioplasty i n 18.5%  same I n s t i t u t e  angioplasty  produced  no  improved  success  artery during to  and  Institute  et.  initial  emergency  patients,  (Levi,  surgery  66%,  the  Blood  reported  (1979),  was  (Greuntzig  i n the  1,500  et.al.  angioplasty.  from subsequent  the  due  and  on  0.95%. C o m p l i c a t i o n s  centres  Greuntzig  angioplasty  treatments  1983,  5%  successful  for  Heart  was  By  be  hospitalization  chances  treated  9 months and  National  centres  mortality  shorter  that  be  by  a t t r i b u t a b l e to  angina),  663  to  required  f o r a mean o f  for  can  relief  patients  major  the  improved  estimate  reported  (measured  In  to  20%.  study  d e a t h s were  advantages  considered  by  a  of  of  showed  73  e m e r g e n c y CABG  PTCA was  6.8%  with  itself.  The  inci-  severe myocardial  ischemia  40 or  infarction  (Greuntzig,  or death  the  (1984)  successful  states  dilation  reduced  infarction.  by d o i n g  procedure  is  stated  cases,  two-thirds  of t h i s  It  eligible 1985).  has  for  60% t o  produced  that  o f CABG  as  80% o f  cases  o f PTCA  of  0.5% t o  I n 5% o f t h e c a s e s ,  by t h e e q u i p m e n t  death  immediately.  restenosis  for  this  1%.  In  occurs  estimated  CABG may  about  within  that  15%  be e f f e c t i v e l y  this  causes a  group  Mortality overall  to  30%  in this initially About  success-  of p a t i e n t s  by PTCA  as t h e  c a n be  months.  repeated  treated  i s t w i c e as h i g h  20% o f  six  group c a n have t h e p r o c e d u r e  been  (Note t h a t  that  Risk  a CABG  successful  fully.  nearly  of the s t e n o s i s .  coronary artery occlusion  myocardial  t o be  1983).  Braunwald show a  was r e p o r t e d  Amiel  (Marquis, e t . a l . es-  t imate) Angioplasty the this  preparation type  initial have 15% have  of  success  long  term  has  treatment.  Research  r a t e o f 60% t o 8 0 % . functional  coronary  infarction,  5%  angioplasty  fails,  deaths.  of r i s k s  and r e s u l t s i m p o r t a n t t o  o f any t o o l f o r e l i c i t i n g  t o 20% h a v e e a r l y total  a range  to  above  Of t h i s  patient  10%  must  and  about  and  The r i s k s  occlusion,  5%  reduced  i n d i c a t e s an g r o u p , 80%  angina  while  a r e : 10% o f p a t i e n t s  t o 10% s u f f e r a m y o c a r d i a l  have 2%  preferences f o r  reported  improvement  restenosis.  patient  an of  These groups a r e not m u t u a l l y  emergency patients  exclusive.  bypass  when  suffer hospital  41 2.7.  The  Cost  Many  of Medical  patients  remainder  of  their  calcium-channel control  their  cost  with lives  blocker  symptoms  (1985) s t u d y  Therapy angina  large  and  a  (Waters,  f o r one  A  patient  using  described  a b o v e c o u l d be The  paying data  national  survey  of p h a r m a c i s t s  TABLE 1.4.  Average Cost  A 1.4  treatment  each  1985).  doses  of  throughout  a  of  segment to  the  $145.00  of  drugs  three  hospitals  the  Waters average  that  prevent  for  of  drugs  treatment  calculated  in  to  the  types  a month  represent averages and  i n order  indicate  with  the  beta-blocker, a  long-acting nitrate  in Table  (Waters,  treated  1985).  month o f  angina.  are  with  i s reproduced  i n Canada  i n Canada  from  a  1984.  of A n t i a n g i n a l Drugs  i n Canada  (1985)  Drug  Dose  Nitrate Isosorbide  Cost  per  month  ($)  dinitrate  Beta-blocker Propanolol Pindolol Calcium-Channel Verapamil Nifedipine  SOURCE: vol.171,  (mg/d)  Walters p. 627  120  15.92  160 320 20  19.84 29.68 29.80  Blocker 480 80  73.15 99.00  (1985) The  Canadian  Medical  Association Journal,  42 8.0  The  Cost  of Coronary  Catastrophic hospitalization number o f grafting  expenditures  authors  (Zook and  CABG a t t h e  and  Lay  Ottawa Heart  were p e r f o r m e d  at t h i s  The  of males  Canadian  average  for incidence  lated  Anderson  (1973).  t o 73 The  artery  years, also average  grafting  $18,415.00 of  (in  the t o t a l  Indirect from  family  an  were not  travel  to  and  50  of  calcu-  a  involving  with  range  costs  were 70%  considered,  the h o s p i t a l ,  coronary  f e e s were 20%  including  of  the  patient  r e c o v e r y time  of  disease.  $6387.00  t o 80%  the  range  of  Professional  hospital  disease  with  of  were  to  episode a  artery  similar  for this  care  a  bypass  these  using  heart  55.3  by  c o s t of  coronary  5 t o 1,  was  the  average  dollars).  hospital  750  coronary  mean age  $9595.00  1983  and  costs  work,  was  1984,  was  the Canadian  c o s t of  and  episodes.  economic a n a l y s i s  to females  The  near  high cost  artery  investigated  In  of  surgery  Coronary  Institute  charts.  39  have  Institute.  for detailed  by  1977) .  (1985)  with  have been documented  among t h o s e  randomly s e l e c t e d ratio  ill  Moore,  i s c o n s i d e r e d t o be  Grafting  associated  f o r the c r i t i c a l l y  Keon, M e n z i e s  grafts  A r t e r y Bypass  to to  30%  total.  time  a t home,  away and  disruption.  In a  recent study  191,000 c a s e s  were  (Metropolitan  Life  the average  o f CABG  estimated Insurance  American medical  o p e r a t i o n were  $21,800 w i t h  to Co.,  performed have 1985).  care charges a 228%  i n the  been  performed  During for a  overall  United  the  States, in  1983  early  1980*s  coronary  bypass  variation  by  state.  43 On  the  average,  71%  of  attributable  to h o s p i t a l  fee.  fees  to  These  a high The  of about  United the in  of  while  varied across  states  company  (1985)  indirect  Between 1974  attributable  Half  half  groups  of  employees  t o work a f t e r  accumulating  returned  t o work  those  9,000  loss per  t o $108,000.  suffered  disability the  receiving  the  of the  a detailed i n the  employees of  recorded  occurred  p a t i e n t s were  CABG c o u l d  surgical  an a v e r a g e  under  recupera-  employees  u n d e r 55  Of t h i s  cohort,  employees  only  9 were  (38%)  still  who d i d n o t  days.  p a t i e n t averaged  wage  those  o f 20 weeks  More  61,000 s i c k  analysis:  N i n e t y - o n e (62%)  days.  The 56  greatest  costs  in this  returning.  Younger employees  compensation indirect  55.  1, 1984.  t o work a c c u m u l a t e d wage  not  sick  than over  work on J a n u a r y  The  of  $5,000  t o CABG  147 a c t i v e  emerged  returned  that  contributed  of the cases  (56%)  employees  work  from a low of about  costs  and  $40,000  the p h y s i c i a n ' s  has  t o work  return  was  study  returning  at  t o t h e i n s u r e r was  o f a g e (44% were b e t w e e n 55 and 6 4 ) .  Two  ting,  29%  and 1 9 7 8 ,  u n d e r w e n t CABG.  1977 and 1978 and o v e r  55 y e a r s  cost  $10,000.  some  States.  direct  costs  Metropolitan  analysis  the  $68,000 w i t h who  did  a range o f  not  return to  l o s s even a f t e r  sick  were t a k e n  into account.  I t was c l e a r  to patients  and t o e m p l o y e r s  f a r exceed  and h o s p i t a l c a r e  the  direct  costs  r e l a t e d to the bypass  p a y and  of patients  of the episode operation.  44 2.9.  The C o s t The  t o be et.  of Angioplasty  total  health care  one-fifth  to  a l . , 1984).  cost  of  including  included  the  angioplasty was a l s o  while  to  year  estimated  surgery Reeder  (Amiel et.  and  coronary  follow-up.  bypass  The  bypass  restenosis.  follow-up  surgery Length  9.3 d a y s  surgery  of h o s p i t a l  i n t h e 1980 s t u d y  cost  of  care  for  an 85%  after  group  r a t e was a c k n o w l e d g e d  cause a r e d u c t i o n i n the  stay  f o r a n g i o p l a s t y and  f o r a n g i o p l a s t y done a t t h e Mayo C l i n i c  The i n c r e a s e d s u c c e s s  costs  f o r 25% o f t h e  R e e d e r e t . a l . (1984) e s t i m a t e d  rate reported  a l .  (56.1%) d i f f e r e n c e b e t w e e n t h e  different:  bypass.  bypass  a t t h e Mayo C l i n i c ,  coronary  with  significantly  the success  69%.  much a s  ($7,508)  of  patients  rate  as  a significant  one  cost  f o r coronary  success  a study-  angioplasty  ($13,387)  13.2  one-sixth  In  (1984) h a v e r e p o r t e d  c o s t of a n g i o p l a s t y has been  1984,  was  only  by t h e a u t h o r s the a n g i o p l a s t y  group.  2.10.  Conclusions This  patients treatment coronary The  from t h e C l i n i c a l  Discussion  s e c t i o n has o u t l i n e d t h e c l i n i c a l with  coronary  is  to reduce  heart  intervention  Surgical  of  disease.  the s e v e r i t y  d i s e a s e and  probabilities  summarized.  heart  reduce  success  intervention  (Angioplasty)  offer  The  options f o r  objective  o f each  o f symptoms a s s o c i a t e d  the  as  treatment  risk  well  premature  as t h e r i s k s  (CABG)  a higher  of  and  probability  with  death.  have  been  non-surgical of p a i n  45 reduction  accompanied  treatment  has  a  significantly treatment. decision these  lower lower  Many in  within  the  willingness on  important patient The  society  the  in medical  to bear  risks  and  the  in Table  1.5  to p a r t i c i p a t e i n the  and and  the  patient  "costs'  e c o n o m i c as  Summary o f Treat  well  result  and  limiting  some  factors  these  include  for  outcomes  It  is  this  addressed  identifies  the  opportunities  treat  coronary  are  personal  and  those discussed both  economic  costs  Outcomes  of  rationality  preference  to  a  Some o f  was  as  Coronary Artery  the  However,  represent  Treatments  of  occurrence.  decision  listed  has  that  outcome p r o b a b i l i t i e s the  a  disease.  patient,  of  as  also  diagnostic,  because  the  but  medical  f o r an e f f e c t i v e  heart  and  probability  summary  The  considered  coronary  of  pain  mortality  practice.  prerogative  their  be  patient  study.  TABLE 1.5.  STEP 1  the  preference  disease. section,  early  of  mortality while  reducing  technical  c o n t r i b u t i o n of  patients  of  treatment  inherent  well  depending  risk  of  are  p r o b a b i l i t y of  are  participation  peri-operative  f a c t o r s must  the  factors  limitations  by  in  to  the  the  in  the  for  artery in  this  costs  to  patient.  Decision  to  Disease.  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 t o symptoms: c h e s t p a i n , s h o r t n e s s o f b r e a t h , unwarranted f a t i g u e , or prostration due to a heart attack.  46 b) The patient enters the treatment phase because i d e n t i f i c a t i o n o f s u b c l i n i c a l symptoms by s c r e e n i n g f o l l o w - u p of o t h e r h e a l t h p r o b l e m s .  of or  PATIENT DECISION The patient decides whether to accept e n t r y to the h e a l t h s y s t e m by a d m i t t i n g o r by i g n o r i n g t h e e f f e c t o f symptoms o f h e a r t d i s e a s e .  STEP  2  DIAGNOSIS 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 achieved v i a case h i s t o r y , electrocardiogram, 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 i m a g i n g s u c h as an a n g i o g r a m . 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 t o r e v e a l i n a c a s e h i s t o r y , and d e c i d e s w h e t h e r t h e r i s k s a t t a c h e d t o diagnostic tests are compensated by t h e v a l u e of the diagnostic information in choosing an appropriate treatment.  STEP  3  TREATMENT OPTIONS  PROBABILITIES of  a)medical  60% to 80% chance o f no p a i n , 20% t o 40% c h a n c e o f same symptoms, l i k e l y s i d e e f f e c t s s u c h as n a u s e a .  management  b)coronary  bypass  OUTCOMES  60% c h a n c e o f no p a i n , 80% c h a n c e o f some p a i n r e l i e f , 1% t o 10% risk of death, 15% to 25% c h a n c e of same pain.  c)angioplasty  undetermined long term o u t c o m e , s h o r t t e r m : 60% t o 80% c h a n c e of p a i n r e l i e f , 1% t o 5% r i s k of d e a t h , 15% t o 20% c h a n c e o f no r e l i e f .  d)lifestyle  no  e)do  nothing  change  data  available.  disease l i k e l y to  progresses, remain.  pain  47 PATIENT DECISION The p a t i e n t e v a l u a t e s s e l e c t s the treatment his/her preferences.  t h e p r o b a b i l i t i e s o f o u t c o m e s and whose o u t c o m e most c l o s e l y meets  STEP 4  PHYSICIAN PREFERENCES Physicians benefit 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 options a, b, and c . The health system reimburses physicians f o r d i a g n o s t i c procedures, 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 COST TO PATIENT a) m e d i c a l management - d r u g s $140.00 p e r month - s i d e e f f e c t s of drugs b) c o r o n a r y b y p a s s 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 d a y s ) - r i s k of death c) a n g i o p l a s t y - s m a l l work loss -morbidity (4-10 d a y s ) - r i s k of death d) l i f e s t y l e c h a n g e -personal e f f o r t e) do n o t h i n g - u n c e r t a i n t y about future health  PREFERENCES ECONOMIC IMPACT - p r o f i t s f o r drug companies -costs of p h y s i c i a n care  - c o s t o f s u r g e r y i s $13,000 -costs of p h y s i c i a n care  -treatment  -reduced etc.  cost  tobacco  -premature  i s $7,000  sales,  l o s s of  life  PATIENT DECISION The p a t i e n t d e t e r m i n e s w h e t h e r t h e p e r s o n a l c o s t s of a treatment a l t e r the step 3 choice o f a t r e a t m e n t 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 health. SOCIAL CHOICE Society determines the p r o p o r t i o n 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 coronary artery disease.  of health care f o r treatment of  48 2.11.  The The  patient most  Research research  questions  preferences  patients  developed this  Questions  have  have used  section.  findings  ought  The  i n the  behaviour  is  to  been the  study  were  based  matter.  probabilities  asked  literature  has  influence  over  later  chapters,  introductory The a)  in this but  are  i n which  Patients  size  patient's must  the  and  value  research  literature  a preference,  has this  judgement.  The  v a r i a b l e s h a v e some or  d e f i n e d more here  questions  d e c i s i o n making  This  e r r o r s of  to  outlined in  previous and  that  available  research  a preference  are  i n order  choice.  The  completely  in  to complete  the  chapter.  are: the  information provided  information  make e r r o r s of  of  listed  this  P a t i e n t s ' p e r c e p t i o n of  The  study  of  independent  expression  f u n c t i o n of  between p a i r s c)  that  research questions  t h e manner b)  a l s o shown  4.  to express  i s v u l n e r a b l e t o a number  premise  o u t c o m e s as  3 and  preference  explored  of  the  reporting  in chapters  shown t h a t when p a t i e n t s a r e  questions  and  the  options  of p a t i e n t p r e f e r e n c e s  reviewed  the  The  described  literature  on  is  in judging  is altered  by  presented. the  proportional difference  outcomes. probability of  that  c h o o s e b e t w e e n two  exchange f o r those  of  a potential  gain depending gains  gains.  or  offer  on  gain  influences  whether  something  the  the p a t i e n t s of  value  in  49 d)  A  patient's  influenced  by  or  a  loss.  e)  A  'right'  the f)  patient The  whether  already than a  severity  predicting g)  coronary  patient  the  are  artery  and  by the  chapter,  preferences  treatment the  a patient  willingness  disease,  described.  by  coronary  a  views  h e / s h e may  influenced  and  take  patient  'right'  following  choices  to  possessed  of  are  artery  In  the  a patient's  Preferences  tions  willingness  to  want  treatment  will to  relating  is  age,  health  methods  a  as  a  is  gain  factor  to  severity  care  history.  these  in  risk.  the  developed to  risk  w o r t h more  a treatment  a patient's previous  be  a  possess.  disease take  with  to  research  of  explore ques-  50 CHAPTER 2 MEASURING PATIENT PREFERENCES: M e t h o d o l o g y  1.0.Introduction This use  of  chapter the  deals  of  reflects  settings,  health  care.  include:  with  preferences  patients'  willingness  of health  and  suggest  preference  risk Plott,  that  some  questions  understanding  outcomes.  comes f r o m  Einhorn  laboratory  aversion  preferences f o r  disease.  The m e t h o d o l o g y  those to the  studied  that  to  s u r g i c a l or  f o r treatment  in a variety  r e l a t e d i r e c t l y to  purposes  f o r treatments  t o pay  students have  validity  as  been  1979;  reviewed  accrue  to patients to  Support and of  simulations  subjects.  S l o v i c and  benefits  of d e c i s i o n s  uncertain  external  patient  of  this  and h o s p i t a l treatment  study stays,  r i s k , and  as a measure o f t h e  o f d e c i s i o n m a k i n g and i n d i v i d u a l s '  college  hypothetical  heart  and t h e  care.  Many s t u d i e s  Grether  on  Methods a p p l i c a b l e  eliciting  used  elicit  f o r coronary  emphasis  patients'  have  to  d e c i s i o n making b e h a v i o u r  measuring  value  t h e methodology of t h e study  questionnaire  outcomes o f t r e a t m e n t reviewed  with  Studies  (McNeil  a l . , 1978;  L i c h t e n s t e i n , 1983). to  a  when we w i s h  strategy  costly  for  study  the  asking  treatments of r e a l  (1981,  p. 81)  decision  making  research  problems  of  They  to contribute  initiate  world  o f r e a l and  et.  Hogarth  of r e a l  preferences  who  with  decisions  s t a t e : "The  that  i s low."  t o an  relies  on  51 2.0.  Structure This  sample,  of  chapter comments  the  Chapter  has  four  on  the  administration  of  the  The  of  subjects  discussion  main components: a d i s c u s s i o n choice  questionnaire, in  The  first  section  calibration  of  subjects,  the  and  assurance.  The  I along  with  to  university ethics  the  patient  appropriate  instructions,  pants.  The  Appendix  literature  two  of  that  patient  behaviour.  Section  the  the  letters  debriefing used  to  results.  in  the in  the  ethics  four the  study,  Appendix  application certificate,  materials  assist  of  strategy,  appears  used, the  the  comprised  patient  itself  strategies,  of  sampling  c o m m i t t e e and  chapter  for  subjects  particiappear  to  i t s influence  reduce  statistical  of  three  r e s u l t s comprise  Sampling Patients for  are  and the  and  reviews  response.  procedures  r e v i e w s methods d e s c r i b e d  shown t o  preferences  rates  subjects  covering  aids  acceptable  3.0.  presents  instrument  have been  determining  the  is  the  in  II.  Section  of  analysis  study  r o l e of  and  visual  measurement  and  the  sections.  patient  of  of  produce  demonstrating factors  the  bias  discussed  results  decision  important  Interviewer also  reliable  in  and  in this  component  of  the  the in  making  achieving  steps  taken  section.  rationale for s e n s i t i v i t y  fourth  in  The  analysis  chapter.  Strategy with  this  coronary  heart  s t u d y b e c a u s e , as  disease stated  were  earlier,  selected heart  as  52 disease  is  health  care  patients study  the  are  to  own  Vertinsky  use  life  to  treated  for  Division  of  65  include  medical  care  subjects in a  In  plan  with  was  an  of  involving  opportunity  considerable  to  realism  in  making h y p o t h e t i c a l c h o i c e s .  A  room  involved  subjects:  the  consumer  addition,  provides  classroom  operating  a major  setting  may  demonstrate  than a p a t i e n t  (Knetsch  and  risking  Sinden,  1984;  a complete  ques-  1974).  heart  questionnaire  of  i n the  research  tionnaire  Canada.  and  d e c i s i o n making b e h a v i o u r s  et.al.,  The  death  in a situation  a dollar  different  his/her  to  the  risking  in  seeking  d e c i s i o n making  student  cause of  resources  who  comparison  very  leading  15  healthy  disease  by  Vancouver answered  responses  by  administering  37  and  physicians  General by  adults  50  in  patients the  Hospital.  A  Cardiology more  hospital administrators  a d u l t s who  being  limited in  order  were f r e e f r o m d i s a b l i n g h e a r t  disease. The patients ing  of  questionnaire  was  with  heart  the  evaluated  coronary  questionnaire  the  skills  of  tionnaire.  This  pretest  Altogether,  115  subjects  naire.  From  subjects  and  group.  No  pretested  this 37  and the  four  14  completed 49  health  in  by  care  Ten  patients,  or  in  formed  were u s e d  i n the  the  section  limited  15  pretest-  professionals  completing  detain  a full  administrators  pretest questionnaires  subjects.  p a r t i c i p a t e d i n the  researcher  is discussed  total,  hospital  disease  on  control  final  data  7.0.  question-  healthy the  ques-  study  analysis.  53 The  patients  cardiologists included  the  Even  over  by  with  was e n c o u n t e r e d  patients.  The  over  670  this  patients  group  65,  an a g e r a n g e  subjects roster  were  tion  Alta  included  and s p o r t s .  short  Lake  making  given  September, completed  at  1985.  Some  five  day d u r i n g  as  the From  Pacific an were  with  felt  researcher  D i v i s i o n or i nthe hours,  and t o  heart  disease.  using  t h e membership  The  membership  a lecture  Health  i n outdoor  of  These  of t h i s recrea-  participated in a i n medical  Forum  audience  in  decision  Vancouver  52 a d m i n i s t r a t o r s ,  in 37  received.  who were a p p r o a c h e d  patients  i n the  b e t w e e n t h e a g e s o f 40 a n d  Club.  of  drawn  of the study. the  office  the researcher  part  number o f  a t home.  patients  Sports  considerable  target  months  hospital administrators  questionnaires  Many p a t i e n t s reasons.  of  of patient  appointments  f a m i l i e s who were a c t i v e  The  questionnaire  the  were a d u l t s  r e c r u i t e d by  of the  organization  typical  Active  t o p a r t i c i p a t e were  scheduled  patients  subjects  the  t o be  period. method  i n the Cardiology  p r a c t i s e every  healthy  month the  by s i x  practises  phase of the p r o j e c t ,  present  be a v a i l a b l e t o i n t e r v i e w  their  achieving  during  recruited  participation,  who a g r e e d  collection  t o be  cardiology  The  was  with  practises  data  was r e q u i r e d  doctors  50 p a t i e n t s  cardiologists' During  five  in  were  in  a  physician  difficulty  from  disease  the p a t i e n t s  study  of p a t i e n t s  selection.  heart  who a l l o w e d  in  recruitment  with  declined  t h e y were  fora  too i l l  v a r i e t y of  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 didn't their  like  Several  to  who  agreed  and  was  by  unable  barrier to  The  diagnosed  20  pain  but  coronary into  was  patient  reasons  d i d not  for  complete  unstable  the One  and  angina  questionnaire patient  for others  not  The  The  two  of  whom  unusable  'heart  one  was  language  patient but  was  before  completed,  not  showing the  the  angina  another  the 14  or  study  group  control'  group  heart  disease  symptoms),  t r e a t e d by  medication  patients in this  study,  or  although  group  some  had  pain.  disease  groups:  No  the  heart  coronary  signs  heart)  time of  the  disease  asymptomatic  valve disease.  heart  p a t i e n t s , and  patients,  naire.  one  to p a r t i c i p a t e  above formed  rhythm of  during  experienced  classified 15  willing;  agreeing  p a t i e n t s with  a pacemaker, or w i t h  tained  were  after  during  questions;  questionnaire  (irregular  experienced  15  they  but  to withdraw.  the  categories.  (disease  The  on  patients described  of  previously  no  p a t i e n t with  became a n x i o u s  focus  a  consisted  or  gave  to p a r t i c i p a t e ,  researcher  although  three  arrythmias  great;  recruited.  50  comprising  the  to  If  was  patients  e x a m p l e , one  hospital  commencing. patient  For  to p a r t i c i p a t e  advised  admitted  some  p a t i e n t s agreed  questionnaire.  a  and  too  participate.  the  was  t i m e commitment was  'research';  refusal  mentally  the  the  p a t i e n t s with group with  group w i t h  angina  pain  were  'mild angina'  con-  'severe  angina'  contained  p a t i e n t s completed  a usable  question-  questionnaire  from  this  group  was  not  55 replaced, of  as  the data  reason  for  interviewed Hospital. unit  the researcher  collection  e x c l u s i o n was  of  determined  with  to  expressed  who were  'angina*  the  angina were  level  by  patient  First,  describing  physician  Second,  the researcher  same.  disability  angina' The  acted  whether presence  for  disease  levels  pain  'mild  three  disability subsequent  estimate  using the  the p a t i e n t ' s  Usually, was  patients  of d i s a b i l i t y  and  Finally,  scale  a l l three  disagreement, the disability  angina'  levels  group,  and f o u r were p l a c e d  while i n the  group.  as c o n t r o l s  of  the d i s a b i l i t y  Patients with the  to other  office.  made an  there  General  influence the  relation  assessments  level.  When  g r o u p o f 15 h e a l t h y  the  in  f o r heart  scale.  disability  a s s e s s m e n t was u s e d .  with  could  using  Three  patient  Vancouver  the p a t i e n t selected his/her  and two were e l i g i b l e  'severe  Institute  The  to the intensive care  i n the doctor's  exercise-induced  the  a s s e s s m e n t s were t h e  patients  patient  and t h e d i s a b i l i t y  stated  physician's  attributable  1).  be e x c l u d e d .  of the  v a r i a b l e that  interviewed  the completion  p a t i e n t was t h e o n l y  g r o u p s were d e t e r m i n e d  made.  history  this  this  (see Chapter  disability.  tors  by  after  patient should  Care Unit  be a  Canadian Cardiology  level  one  that  i n the Coronary  preferences  The  this  The p a t i e n t a n x i e t y  was  patients  that  had d e t e r m i n e d  effects symptoms  a d u l t s and 37 h o s p i t a l  so t h a t a d e t e r m i n a t i o n of  diagnosis  influenced  of  heart  could  administrabe made o f  disease  and t h e  d e c i s i o n making b e h a v i o u r .  In  other  words,  nature  of the d e c i s i o n  viour. to  the object  Subjects  those The  their  was t o in  understanding  were t o make c h o i c e s situation.  52 h e a l t h y  s u b j e c t s were  control  had  diagnosed  disease.  They  were  then  imagining  that  they  would  and t h a t  researcher angina  would  described  what  could  u s e d was  limit  taken  Cardiology for  they  Pain  as a F a c t o r  Patients spectrum  of  disease.  Some  moderately order  for  preferences was  pain  to  a  angina  by  1.  of l e v e l s  that heart  i nthe  t h e f u t u r e . The be l i k e  and how  description  of pain  were g i v e n  of  imagine  sometime  might  Subjects  similar  the questionnaire  in  The  beha-  coronary  symptoms  pain  activities.  angina  as  the Canadian a reference  angina.  i n D e c i s i o n Making  selected typical  for of  this  meaningful  f o r morbidity have  analysis  coronary while  p a i n due  accompanied  of coronary  artery  others  to angina.  of the questions  understanding  was due t o t h e symptoms  to represent the  with  no p a i n ,  and t r e a t m e n t s an  study  patients  patients experienced  to  of  answer  o r s e v e r e l y d i s a b l e d by c h e s t  important  patient  were  presence  to  of the  making  situation  asked  r e q u i r e treatment  grading  caused  decision  experience  from Chapter  the d i s a b i l i t y  4.0.  asked  normal  Institute  the  the importance  in a real  i n an h y p o t h e t i c a l  doctor  future,  determine  were In  r e l a t i n g to by r i s k ,  i t  o f how d i s a b l e d e a c h heart  disease.  Each  57 patient  was  asked  current  therapy,  asymptomatic disability disease  caused  In  meaningful subjects  one,  pain two  were a n a l y s e d of  respite periods  the  comparison  at  patients  whose  to  for  pain  compensate f o r t h i s  they  during  felt  periods  Schelling's since The  the  them of  pain.  (1985)  pain  interesting  to  they  This  of  of  was  was  are  would the  strategy  that  asked and  to  responses The  expressed  possi-  during  expressed  expected  best  a  during  (Christensenas  (Schelling,  reflect  a result  of  1985) .  To  their  to  needs  questionnaire  as  well  as  was  because  of  adopted  people discount s u f f e r e d doesn't  angina pain  not  made w i t h i n  severity,  become s u s p e n d e d relief  disease  which  angina.  preferences  during  have a l r e a d y  aspect  heart  p r o b l e m , p a t i e n t s were e n c o u r a g e d  be  finding  o f many  questionnaire  pain  pain,  c h o o s e t r e a t m e n t s whose o u t c o m e s as  the  may  other  any  pain.  preferences  experienced  the Each  P a t i e n t s were  i t s current  without  compared  need  1984).  years  1984). True values  overwhelming  somewhat  pain  five  pain,  towards  or  attribute  patients,  violating  pain,  when t h e y  Szalanski,  an  comparisons  were e x p e r i e n c i n g  from  disease  pain  the  patients  attitudes  avoid  and  Twenty-nine of  bility  is  continuing  of  group.  (Christensen-Szalanski,  visualize  visualize  to  heart  pain  duration  demographic data.  his/her  in this  of  and  limited  coronary  in patients  between  onset  described  by  order  only  the  to provide  experience  states.  to  and  patient  found  The  to d e s c r i b e  i s that  the  past  hurt  highly,  them  now.  p a t i e n t s know i t  58 will ly  be b a c k , and remember w e l l what  true  viour  o f most r e c u r r i n g o r  responses  different extreme,  is  shown t h a t  than  t h e added  then,  pain  self  confusion  there  is  an a d a p t i v e  (Arrow,  to  the  situation  ing  this  take  some  that  caused  study  of  5.0.  Introducing At  collected  in  questionnaire age, type,  a  patients  spent  of  remains  manner  response  to the  of each  contained  sex, health length  adaptive  Subjects  the outset  There  not knowing whether  merely a short-term  a short  symptom  as much  and  make  that  1984).  the pain the  may  However,  i n pain i s by  altering  dilemma  affect-  a patient's preference  is  to pain.  to form  demographic  v a r i a b l e s were  a  history.  patient  (see  Appendix  h i s t o r y , m a r i t a l s t a t u s , number symptoms,  they  Questionnaire  interview, similar  although  1971).  The p e r s o n  action to a l l e v i a t e i t .  which  on  more s e n s i t i v e t o a s t a t e o f  than a s t a t e of non-pain or p l e a s u r e .  motivated  be b a s e d  choices  as a d i s e a s e  to being  beha-  R e s e a r c h has a l s o  (Christensen-Szalanski, value  to  pain,  i n the  of p a i n  i s general-  Understanding  limiting.  not c o n s i s t e n t  This  appears  labour  c a n be c l a s s i f i e d  true preferences  pain.  the case of  people are  alter  patn  angina  i n t e r m i t t e n t and  even w i t h o u t Pain,  chronic  to chronic  criteria  i t is like.  lifestyle  as h a l f an h o u r  risk  I)  The  asking:  of c h i l d r e n , j o b factors.  describing their  Some  history.  59 The taken to  reason  by  the  p h y s i c i a n was  encourage  provide  for asking  the  the p a t i e n t ' s heart with  previous could  seeking  the  care  of  between  from  group w i t h  a l l  identify  It  p a i n . The  was  to  is  also  course  were of  not the  to l i v e .  by  also  important because  important  choices.  The  control  in  g r o u p and  methodologically  asked  a  This question  heart  history to  subject  to have  every  experience.  i n order  to s t a t e  pace-  were a v a i l a b l e  important  to d e s c r i b e  disease)  that  reducing the  for taking  that data  their  treatment  cardiac arrythmias, factor  for  data  d i f f e r e n c e s b e t w e e n p a t i e n t and  However, s u b j e c t s were a s k e d expected  comfortable,  d i s a b i l i t y caused  disease  reason  ensure  already  to  important  disease  a history  r e s e a r c h e r , and  provided  r e c e i v e t h e same q u e s t i o n n a i r e  Patients future  angina  patients  heart  with  an  heart  s i m i l a r i t i e s and  groups. subject  the  the  and  treatment  patients  disparities  to  T h i s h i s t o r y was  in  v a l v e d i s e a s e was  repeat  patient feel  of p a i n  coronary  m a k e r s , and  disease  the  experiences  influence  behaviour  kind  disease.  asymptomatic  health  h a v e an  to h e l p  p a t i e n t to communicate  i n f o r m a t i o n on  patients  p a t i e n t s to  the  their not  prognosis  to cause  number  of  (the  anxiety.  years  d i d c a u s e some a n x i e t y f o r a  they few  patients.  6.0.  The  Subject's  Subjects Potential  are  problems  Role active  participants  that could  develop  in  i n the  any course  experiment. of  adminis-  60 tering  the  subjects what  questionnaire  be  motivated,  cues w i l l I n any  tions  Orne  inquire  Subjects hours this  the  i f not  at  has  the  may  be  asking: this  how  will  the  research,  and  up? type, the  of  certainly subjects  duration  tend  the  of  the  1962,  p.  belief  that  is therefore  For  this  study  offered  a  summary  feedback  on  their  evident In that to  report  present  of  preferences  findings.  were g i v e n  d e c i s i o n making b e h a v i o u r s terms  convey  of  the  eliminate  outset. they  i n the  demand  purpose of bias  by  When s u b j e c t s  appear  1962) . I n  solving  normal  mechanism  meaningful  understand  a d d i t i o n , the the  (Weick,  for  effort  subjects  questions, making  1967).  of  research),  explaining  t o make e v e r y  toward  the  this  which the  and  research  of  important. and  wanting the  responses.  the  (cues  strived  clearly of  study  has  for  Part  experiment  purpose  honest  tasks  researcher  purpose  t o be in  the  do  experiment.  summary o f  i n the  the  the the  often  patients  a verbal  characteristics  place  were d e b r i e f e d  Any  exhibited  the  research  make a c o n t r i b u t i o n t o k n o w l e d g e and subjects  to  156).  may  reason,  expecta-  during  meaningless  (Orne,  by  role  e x p e r i m e n t e r , and  perform  compliant  stimulated  that  or  to  some m u t u a l  outset,  the  purpose  t o be  by  perceive  shown  observed  effort  behaviour  they  this  control  about  have been  i n an  will  of  (1962)  under  explored  patients pick  become d e f i n e d ,  themselves  how  experiment  research.  not  the  were  at  the  research  helpful  (Orne,  actively  worked  been s u g g e s t e d experience  as  a  more  61 A potential patients from  with  the  addition, surgery  source of bias  pain  and p a t i e n t s  treatment  seeking  some p a t i e n t s  which  may h a v e  For  example, a p a t i e n t  of  death  may  anticipating reduce  feel  this  the  with  without  pain,  behaviour angina  had  that  a  may  that  10% r i s k  believe  i t  treatment  reinforced  subjects words  7.0.  McNeil  Interviewer  the  in  of  the researcher's  view  in  a  neutral  researcher's anxious.  Hospital  arisen  pain.  undergone  towards  surgery  risk.  a  10% r i s k  i s 'low', w h i l e  a patient  is  'high*.  To  could  by name.  t r y to  generate, This  choice  a l . ' s (1978) f i n d i n g t h a t  treatment  In  bypass  surgical  with  experience  administration  test  in  have  had  an a v e r s i o n  many  to the  Bias  experienced  questionnaire  r i s k of  therapy".  evaluate  professors  be  et.  i n a study of cancer  "radiation  To  by  could  already  o u t c o m e s o r t r e a t m e n t s were n o t i d e n t i f i e d was  towards  due t o a n g i n a  altered attitudes who h a s s u r v i v e d  risk  bias  i n the a t t i t u d e s  decision ability  manner.  One  an i n t e r v i e w  skills  participated  staff in a  research to conduct social  questions  physician structured  and  assessed  the researcher's  and  answering  patient's  participated a structured  worker  s i t u a t i o n i n order  i n presenting  A senior  of the q u e s t i o n n a i r e ,  skills  questions.  to  inter-  to evaluate  a t t h e Vancouver  at taking  in a  completed the  patients  interview  two  as a  who  the may  General  'patient'  a patient  history  62 The  author  interviews  the  employed.  of  First,  physician  the  employees,  who  and  to  raised,  for  fine."  each  item  on t h e patient  for patient  provided  Patients  were r e m i n d e d  questions each  except  that  aids  8.0.  Assurance  research. patients in  a real  This  study  about  their  the q u e s t i o n n a i r e  phenomenon dealt  with  letter  the of  verbal  standardized  prepared.  The  time a q u e s t i o n of approval  were no r i g h t for  was or  patient  care  (Mooney, 1977, p . 1 3 2 ) .  was  f o r thea i d .  and i n m e d i c a l  anxiety  and a f t e r  answers.  each q u e s t i o n  a need  i n medical  f e e l i n g s before  was  a  t o nod and s a y , " t h a t ' s  there  or not the p a t i e n t expressed  is  of  a memorized  any s i g n s  made, w h e t h e r  Anxiety  always  of h o s p i t a l  those the  questionnaire,  c o n s i s t e n t use of t h e v i s u a l  Patient  were  manner.  d i d n o t show  responses,  to  provided  t h e same e x p l a n a t i o n  the researcher  i n the  t o t h e p a t i e n t by  typical  identical  and  bias  The r e s e a r c h e r  tag  researcher  subject  anticipated  and  Finally,  office  the  each  provided  disapproval  the p a t i e n t .  structured  f o l l o w i n g steps  introduced  delivered in a friendly  for  researcher  an  control  the  identification  used  introduction  was  a l l the  to  questionnaire  and  Second,  Third,  In o r d e r  recruited  physicians.  introduction  conducted  the researcher  wore a w h i t e c o a t  answer  study  (questionnaires).  administration  the  of  by  asking  they p a r t i c i p a t e d  63 Less heart  anxiety  disease  be  real  able  noticed  patients.  (1977) f i n d i n g not  was  that  to  take  i n the  This  was  individuals into  healthy  subjects  expected,  based  in a hypothetical  account  the  anxiety  than on  in  the  Mooney's  situation  associated  may  with  a  risk situation. Patient  A detailed patients  anxiety protocol  that  the  developed  son,  al.,  adapted  also  for  will  f o r use  1984).  by  The  1.  Patients  2.  The  are  i s found  assured  researcher  of  explains  assurance not  the  formal (a  in this  covered  (1984) and  in  listed  i n Appendix  assurances.  letter  i n t e r f e r e with  subjects  items  f r o m Thompson e t . a l .  a s s u r a n c e document  a l l e v i a t e d with  patient  research  ment) was et.  was  telling  their study  the  treat(Thomp-  letter  b e l o w . The  were  patient  I.  a n o n y m i t y and c o n f i d e n t i a l i t y . the  r a t i o n a l e and  importance of  the  research. 3.  The  questions  4.  Any  purely  5.  Props  and  as how  6.  Patients  are  7.  Patients  are  has  close  dice  assured  research  subject  University  of  to  project,  s i t u a t i o n s as  diagrams be  that  debriefed  real  s i t u a t i o n s are  and  t h e y may  to  are  clearly used  to  is feasible.  identified. explain  the  answered. there  and  are  asked  made them more a n x i o u s a b o u t The  was  as  hypothetical  such  questions  are  scrutiny  British  Columbia.  of The  ' r i g h t answers'.  i f answering  their  including  the  no  questions  condition.  the the  the  complete  questionnaire,  E t h i c s Committee of  project  was  also  the  evaluated  64 by  the  the  Cardiology  Vice  Written any  President  and D i r e c t o r  of  from these  three  permission  patients  could  Following give  D i v i s i o n of the Vancouver General for  the hospital.'  s o u r c e s was r e q u i r e d  before  participate.  hospital  written  consent  the  patient's  given  Research  H o s p i t a l and  regulations, patients  to their  physician  name. The  before  consent  form  were r e q u e s t e d the researcher also  to was  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 There  treatment study,  are  many  factors  f o r coronary  these  have  heart  been  hospital  stay,  and  worth measures  net  and h e a l t h  little  influence  ada.1  Choice  disease heart  subset  of  limited  to a patient's  For  Choices  treatment  access  that  b e c a u s e most are  not able  based  because  alter  of this length of  on r e a l  income  they have  to health  could  choice of  the purposes  to pain, morbidity,  outcomes.  treatment  course of progressive Klein  disease.  patient's  has been e x c l u d e d  disease  relevant  have been a v o i d e d  on a  of a  Choice  care  the course  interventions  very  i n Canof t h e  i n coronary  to s i g n i f i c a n t l y  a l t e r the  atherosclerosis.  (1983) has a l l relevant  stated  that  people  think  a t t r i b u t e s when t h e c h o i c e s  about  only a  a r e 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 costs of s u r g i c a l treatment f o r coronary h e a r t d i s e a s e which a r e p a i d by M e d i c a r e , and t h e d r u g costs of medical therapy f o r coronary h e a r t d i s e a s e w h i c h a r e p a i d by t h e p a t i e n t .  65 varied.  For  each  relevant  across  will  evaluated  to  be  heart  attributes  by t h e p h y s i c i a n a c t i n g a s an a g e n t  or a d v i s o r  problems  attributes.  extreme  points.  health,  may  but  in  value  to  for  offer  due  be  of l i m i t s  too d i f f i -  on a b i l i t y t o  hospital  with  choice  severe  of  this  difference  difficulty,  to 'very  pain.  the  c h o i c e s w i t h i n a range of  t o be a 'good o u t c o m e ' , s u c h  disability  be  i s known a s  i n good  b e t w e e n two weeks a s an  i f there  these  isa  two s t a t e s , To compen-  anchors p a t i e n t  b a d ' o u t c o m e s , and i t a t t e m p t s  of a t t r i b u t e s  finding  to  So, even  questionnaire  subjects  considered  two weeks  a n d two  between  near t h e  distinguish  may n o t be p o s s i b l e .  good' and ' v e r y  process  values  distinguishing  from s u r g e r y angina  o f outcome  demonstrate e r r o r s of  p a i n and  The  permanent  may  have d i f f i c u l t y  recovering  home w i t h  this  outcome  the  e x a m p l e , p a t i e n t s may r e a d i l y  comes.  an  to  together  d i f f e r e n c e f o r the patient  measurement  responses  they  hospital  at  arise  close  For in  sate  because  will  d i f f e r e n c e of g r e a t e r magnitude than  b e t w e e n two weeks  real  options.  a number o f a t t r i b u t e s  may  Values  proportional  invalid  few a t t r i b u t e s a r e  information.  Some  weeks  a  Many  f o r some p a t i e n t s t o u t i l i z e  process  only  t h e range o f treatment  the p a t i e n t , while  cult  patient,  of treatment  an outcome c o n s i d e r e d a s no more a n g i n a  a 'bad o u t c o m e ' s u c h 'anchoring'.  out-  by most  p a i n ; and  as death o r  66 10.0.  Measuring Utility  of  one  Merz,  reflects  outcome as 1983).  101).  change example,  life,  if  a  For utility  or  reduction  therapy,  disease,  and  disability,  costs,  and  drugs,  death  the  also  i t s value  cancer  with  value  Raiffa,  1976;  the  "worth of  of  how  preferences change.  of  has  the  capable  o n l y one  lung  of  as  has  a  For  the  living  lung  a  1976,  environment  a  lung  normal  measurable  a p r o p o r t i o n of  d i s e a s e , the  components, both  (or  costs a  outcomes)  outcomes  continued  (Kassirer,  of  firm  1976,  the  of  the p a t i e n t ' s  as  diagnosis  positive  treatment (Berwick  the  or  of  and  drug Wein-  emotional  hospitalization,  o r more s e v e r e p.  and  pain, elimination  i n c l u d e : p h y s i c a l or lengthy  treatment  i n c l u d e : 'cure'  hospital  pain,  side  continuing  155).  f o r a treatment  s u b j e c t i v e value to  heart  f r o m symptoms s u c h  disruption,  preferences  of  to  the  decision (Lindley,  the  coronary  dollar  Negative  only  in  components  family  Stated  and  a description  otherwise  establishing  from  a  a number o f  relief  of  1985).  effects  of  Positive  heart  outcome o r  (Keeny  i s u s u a l l y expressed  with  i s made up  the  an  in perfect health.  patients  negative.  is  of  i s attached  of  with  living  number  living  value  factors  and  Study  another  scale is  worth of This  of  to  outcome  patient  surgically  utility.  stein,  the  various  the  value  or  Heart  desirability  compared  A utility as  removed  the  i n the  Its numerical  consequence" p.  Utility  outcome  treatment  family.  A  to  are  i n d i c e s not  the  patient  number of  the  but  study  67 interviews interest  (10%)  i n the subject's  Von the  an  individual  B  estimation  who  t o o k an a c t i v e  participation. (1944) h a v e  o f an o r d i n a l v a l u e  prefers A to  than  Morgenstern,  to  members  the  o f f e r e d an e x a m p l e  for utility.  50-50  Briefly, " i f  combination  of  p r e f e r i n g C t o A and A t o B) t h e n h i s p r e f e r e n c e  i s greater  and  family  Neumann and M o r g e n s t e r n  of  (while  included  1944, p . 2 0 ) .  C can r e s u l t elicit  the preference  from t h i s  of C  o v e r A"  B  of A over  (Von Neumann and  At l e a s t  an o r d i n a l p l a c e m e n t  choice.  The  patient preferences  uses  this  and C  questionnaire notion  o f A, B  developed  o f measurement o f  utility. Torrance  et.al.  develop  a  states.  Subjects  health the  (1982) h a v e d e s c r i b e d  cardinal  states  ordering  were a s k e d  on a  between listed  the  value  of  of  various  of  patient.  the u t i l i t y  place  on  health  states.  as  In other  state  i f a heart  under  the  threat  threat  will  have a measurable u t i l i t y .  allows  the combination  denominator,  such  of  a  that  independent  words, even  a myocardial  relative  of  to  between  difference  Perfect health  utilities  of the  was  patient will  infarction, Using  life  measure t h e  prognosis  of the  always  l i f e without  a  utility  o f many a t t r i b u t e s o f h e a l t h 'quality  health  zero.  e t . a l . (1982) s u g g e s t e d  the health  the  used t o  corresponding  The s p a c i n g  1  data  they  of various  arrows  thermometer .  a s 100 and d e a t h was l i s t e d  Torrance value  to  'feeling  a r r o w s was t h e s o u r c e  of  a method  years'.  live the  measure  i n t o a common This  measure  68 discounts  years  years  of l i f e  order  to  (1982) years  used  explanation  with  p . 154)  person  utility  is  function  indifferent  the  free  to  but  assign  i s determined  choices  health  absolute  If  et.al. f o r 'x'  a  utility  utilities for  utilities  arbitrary utility  In  The p o i n t o f  yielded  "relative  as f o l l o w s :  disabled  Torrance  i nperfect  noted,  more  o f good h e a l t h .  f o r 'x + y ' y e a r s .  singular  (1968,  As L u s t e d  t o one y e a r  living  i l l health  between t h e s e  so t h a t  of p r o b a b i l i t i e s ,  a t r a d e - o f f between  i n d i v i d u a l a r emeasurable,  The  is  an  and l i v i n g  measure.  or d i s a b i l i t y  a r e then e q u i v a l e n t  avoid  indifference  an  of sickness  are not.  values,  and a  thedecision  maker  b e t w e e n two a l t e r n a t i v e s , t h e e x p e c t e d  u t i l t i y of  a l t e r n a t i v e s i s t h e same." Components  are  actually  prominent examined pain,  of  the a v a i l a b l e  vectors  of  choices  outcomes  in  this  prominent  study: a  of death.  attribute  hospital stay,  Patients  of  the  e x a m p l e , a p a t i e n t may have i d e n t i f i e d  'being  as able  t h e most to play  important  golf  o f such  a vector  by a were  c o n v a l e s c e n c e a t home,  were a s k e d  treatment  not s i n g u l a r , but  may be i d e n t i f i e d  a t t r i b u t e . A number o f c o m p o n e n t s  and r i s k  garden'  that  are  to identify  outcome  'being  able  t h e most  vector. t o work  For i n the  a t t r i b u t e of convalescence; or  a s t h e most  important  outcome  of pain  control.  11.0.  Measurement In  Strategies  the patient  preference  study  simple  measurement  stra-  69 tegies  were  found, less  followed,  p a t i e n t s would  of  how  understand supported tering  they  by  were a s k e d  bar  the  g r a p h s and  with  chance of  four  Subjects  were  outcomes,  with  risk,  asked  capsules,  (see  Appendix  describe  of  o u t c o m e s ) . They were a l s o asked outcomes.  preferences  were  questionnaire shown  to  standard and  chosen  and  be  Several for  because  more  significantly  gamble,  ease  of  time-trade-off  was  adminisand  question  was  representing  a  II) preferences  to of  costs  (or  s t a t e the eliciting  methods  techniques,  risks of  patient  have  T h e s e methods  for  value  administration  complex  better.  patients  questions  each  b e n e f i t s and  methods  (1983) regard-  researcher  their  outcomes w i t h  alternative  attendant  help  c o i n s . One  pill  to  To  subjects'  d i c e and  Barnes  questionnaire  the  alternative negative  and  preferences  the  d i a g r a m s and  empty  treatment  their  answered  probabilities  Beach  to communicate.  of  questionnaire  illustrated  t h a t , as  t r y to d e s c r i b e  probabilities  demonstrated  25%  assuming  of  the  not  been  included:  scenarios,  the  ranking,  ordering.  11.1.  Standard The  ences  Gamble and  'standard  and  asked  to  s t a t e an  in  scenario.  a  g a m b l e ' method  in a situation  Neumann  Comparisons  of  Morgenstern  uncertainty (1944) .  equivalent T h e y may  of  eliciting has  In  this  outcome t o a  a l s o be  asked  been  to  personal  prefer-  attributed  to  Von  method, s u b j e c t s  are  50-50 gamble  described  c h o o s e between a  50-50  70 gamble and  an i n t e r m e d i a t e  S u c h an i n t e r m e d i a t e The b a s i c above  questionnaire. different described  The  first  of  These gambles o f f e r e d number  o f bed  Subjects  rest  in  long  Or a s h o r t  rest  the  days  were a s k e d  bed f o r s u r e  Each  equal  rather  hospital  1  i n more  methods  scenarios The  of  to  outcome c o u p l e d  (Von Neumann and  how  of the present method  with the  Morgenstern,  chances at e i t h e r  to s t a t e  detail  prefer-  alternative  due t o t r e a t m e n t  than  equivalent .  for utility.  two  used  of a p o s i t i v e outcome  certainty.  f o r the development  subjects.  a negative  with  'certainty  scale  useful method  to  a  evaluated  were  the p r o b a b i l i t y  illness.  of  that  alternatives  probability 1944).  (1975)  occurs  were d e s c r i b e d  o f an o r d i n a l  and Wong  measurement  that  is called  p r i n c i p l e s o f t h i s method  Vertinsky  large  outcome  i n the d i s c u s s i o n  ence  outcome  a small  or  o u t c o m e s f o r an  many  days  they would  t a k e a gamble o f f e r i n g  either  a  stay.  subject's  utility  alternative  bed  was rest  calculated days.  from  stated  The f o l l o w i n g  utilities  formula  was  used: u(x) The s m a l l large of  number o f  number  days of  equivalent  u(b)  bed r e s t  was  s e t to one.  generated  set  to zero  I n t h i s way,  a data  point  used  and t h e  each  choice  to create  a  measure.  Subjects standard  u ( a ) + 0.50  (up t o 15) was  a certainty  utility  = 0.50  in  the Vertinsky  gamble method  to  be  and Wong 'easier  (1975) s t u d y  to handle'.  found the  Consequently,  71 this  method was  utility to  adapted  f o r years of  to the p r e s e n t study  life  with c e r t a i n t y  versus  risk  patient's  of death  due  treatment. The  standard  scaling  by  scenarios  higher  gamble t e c h n i q u e has  Llewellyn-Thomas were  evaluated  by  used  raters  values  to  et.al. describe  using  both  method  in  carcinoma The  study  visualizing  for  was  and  developed  et.al.  scales  risk.  Their  good  et.al.  method  or  appeared  t h e y would  they got  the a  used  above.  gamble  technique.  used  a scenario  f o r treatment  assist  Diagrams  were  Consistently  probability to  study,  which  demonstrated  (1978) w e r e u s e d  (1978) u s e d  outcomes  patients  similar  in  for  success.  of  to  in  those  the p r e s e n t  how 25  get  a 50/50 gamble s t r a t e g y e x p r e s s i n g an  involved many years.  t h i n k o f a 50/50 gamble  offered  the  category  this  states  (1978)  with  from  was  for patients  10  lung  to  study  probabilities.  to choose  health:  In  preferences  probabilities.  questions using  utility  and  diagram  by M c N e i l  were a s k e d  health  Pauker  patient  separated  a  the  McNeil  of  the bronchus  scenario  statement  (1984).  were a s s i g n e d u s i n g t h e s t a n d a r d  a of  b e e n compared  techniques  M c N e i l , W e i s c h s e l b a u m , and  to  t o measure  five  a v e r s i o n to  basic  steps.  they  would  years  of a  coin  t h e l o n g terra s u r v i v a l ,  alternative,  c h o i c e between  First, like  Second, these p a t i e n t s  i n terms  death. taking  Third, the  to  gamble o r  surgical patients  to l i v e were  toss. i f tails  these  develop  asked  I f heads appeared  patients stating  in  a  were fixed  72 period  of  certainty patient  life  equivalent  to  e q u i v a l e n t , or guaranteed  example,  the  5 years)  researchers  took  and  the  asked  equivalent  in  survival).  The q u e s t i o n was t h e n  of  before  years  step  1  and  Finally, the  death  f o u r was  One heart  who  than  and  3 years  this,  of  a choice  equivalent  averse  a  equivalent (for using  as  zero  using  t h e new years  b e t w e e n a 50/50  by  from  the p a t i e n t .  t h e 50/50 gamble versus  of  gamble  o f 10 o r 25 y e a r s  selected  of  to  survival  a n d 10 y e a r s  c h a n g e s were  outcomes.  to reduce  causing  of  rather  o f good  a  between  choice of  of s u r g i c a l  than  take  equivalent  of s u r g i c a l  with  adjustment  effects  a  one.  death.  To  sequence of  was made b e c a u s e  certainty  dealing  with  equivalent.  o f an e r r o r i n t h e f i r s t  e r r o r i n a l l t h e answers, each  independent  utility  e t . a l . (1978)  had d i f f i c u l t y  each newly g e n e r a t e d  the p o t e n t i a l  t h e 50-50  was t o m e a s u r e t h e  made t o t h e M c N e i l  This  death,  health.  the r i s k  p r e t e s t group  a compound  w r i t t e n a s an  the r i s k  study  of avoiding  i n the study  substitution  In o r d e r  was  this  more a v e r s e  again,  the choice  repeated  were  patients  probabilities patients  gamble  (written  method b y r e p l a c i n g t h e c e r t a i n t y  answer  the  the c e r t a i n t y  death  purpose of the present  accomplish  the  (The l o w e r  survival.  gamble b e t w e e n d e a t h  to  survival,  e q u i v a l e n t and immediate d e a t h ,  Patients less  of  certainty  step  a guaranteed  place  a  certainty  chose  gamble.  was t o r i s k . )  Fourth,  5  that  Patients  question  experienced  less  73 difficulty  and  principle  behind  altered  11.2.  rather  Ranking  demonstrated  than  and  B e a c h and et.  simple voting. scales  The yield  derived  from  the  authors lowest  certainty  Barnes  an the  expanded  subject  determined  that  that method  method"  (Beach  against  preferences  i n an  Pliskin attempt  an  et.  utility  ted  with  pairs  was  f e a s i b l e i n the (the  decision  function.  of  choices  number o f  v a r i a b l e that  attribute  .89  and  simple .9  with  scale  use  the  because Isen  and  rating  derived  p.423).  The  i t had  the  and  s c a l i n g to  a  ordering  ordering  1983,  method  of  rating,  with the  that  included  seven p o i n t  Barnes,  voting  that  a  choices  in  order  Instead,  the  patient  asked  (1985)  radiographs had  Stillwell  Patrick  demonstrate  risk situation.  and  Pliskin  These  preference  "the  successful  of  work o f  approximate measures  a l . (1985) h a v e s t a t e d  assessment  the  methods s t u d i e d .  hypothetical  attribute  measure  the  p r o b a b i l i t i e s were  preferences.  and  the  c o r r e l a t i o n with other report  on  correlates  ranking  recommended  the  Scaling  (1983)  ordering  the  of  equivalent.  demonstrate s e v e r a l  study  understanding  when  method, a seven p o i n t  points  (1983) a l s o  second  the  in e l i c i t i n g  ranking  better  questions  Preference  a l . (1982) t o  were u s e f u l  from  these  a  rank  study  performed  influence  ( p r o b a b i l i t y of  to  over  a tooth  the  the  patient to  create may  be  pairs.  because per  the  y e a r ) was  probability  lesion).  need  not  a  two  presenRanking outcome also of  a  the  74 11.3.  Time-Trade-Off Time  trade-off  equivalent Torrance asked  t o t h e Von et.al.  been  Neumann and  (1982).  In  to determine a p o i n t of  years) The  has  with  a chronic  interviewer  Since  no  were u s e d ,  attitudes  measure  the  of  standard  Torrance  the  question researchers  mean  empirically gamble  by  p a t i e n t s were  between a l i f e t i m e  a shorter  risk,  be  study,  and  the  toward  population  Morgenstern  indifference  illness  the p a t i e n t  to  the  supplemented  lotteries  considered  (70  but  healthy  life.  with  visual  aids.  could  not  instead  they  evaluate  developed  a  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)  patients  to  scale attributes  one  very  bad  and  the  ordered An  by  life  12.0.  of  the  of with  responses life  with  moderate  table  asking  questions  outcome. by  who  found  angina  of  the  Statistical this  that  asking  subjects  a n a l y s i s of  strategy.  t i m e - t r a d e - o f f s t r a t e g y has  severe  of  h e a l t h outcomes s t a t e d t h a t  15  worth  less  in  reported  a study  was  subjects  been  than  10  years  of  angina.  Administration groups  good  to choices  Administering  chosen over  that  of h e a l t h s t a t e s o f f e r  is simplified  e t . a l . (1984),  physician years  very  preferences  example  Read  one  recommended  so  the  Questionnaire  of  the  questionnaires  that participants  for clarification  and  to  would  offering  individuals  feel  more  additional  was  comfor-  comments.  75 As  stated  doctor's logy  earlier,  office  of  The tured  27%  by  the  of  subject  in  the  researcher  questionnaire  structured Torrance study  of  to  questionnaires understanding  prepared  visual  of  respondents.  to  complete  from  the  not  in a  Cardio-  H o s p i t a l , and  of  health  about 17%  in  from  the  a  an  struc-  states  have  et.al.,  s t a t e s where  e t . a l . , 1982).  help  as  health  (Kaplan  have adequate  1979)  participation to i n d i c a t i o n s  Several  reading  patients  skills  researcher,  to  making  do the  essential.  for health  problems.  i n the  78%  present  of  completed  s t a t e s had  confusion) To  increase  study,  aids.  Usable data  Three p a t i e n t s  interviews  some u s a b l e  when t h e  was  data  interviewer the  the  not  difficulties and  the  from over  95%  (4.4%) w e r e u n a b l e , o r These q u e s t i o n n a i r e s  (they  usable  researcher  collected  in a  did  number o f  patients with  c o n c e p t s were a s s i s t e d by  several questions.  unwilling,  were  excluded  analysis.  Torrance questions  rates  (Torrance  subject  clarify  i n the  essentially  interviews  about  without  preferences no  General  administered  e t . a l . (1982) f o u n d  demonstrated attempt  was  did  interview  room  p r o h i b i t e d were u n u s a b l e due  confusion study  administered  group p r a c t i c e .  confusion  was  was  waiting  Vancouver  interviews  present  large  Structured  subject  of  questionnaire  to a  the  questionnaire  interview.  while  in  of  a cardiology  demonstrated  the  adjacent  Department  office  the  et.al.  were w e l l  (1982) accepted  found by  the  that  patient  general  preference  public. A  random  76 sample o f s u b j e c t s by S a c k e t t  generated  and T o r r a n c e  Although,  preferences in detail,  on m a c r o - c h o i c e d i f f e r e n c e s Cassileth  et.al.  information patients patients  found  wanted wanted  et.al.  that  33% o f  found only  that  confirm being  that  older  involved  questionnaire  was  physician,  willingness  low  rate  study  explored  patients  in  i n choice  the  while  (increasing the to p a r t i c i p a t e  b e h a v i o u r and  older  a n d s p o u s e s and  defer of  decisions to a m b i g u i t y and  treatment  and House are less  (1984)  while also  interested i n  patients.  study,  even  the patient's  convenience was v e r y  Younger  decisions.  ambiguous  than younger  present  administered  to  effect  diabetes  patients.  w h i l e many  make  Pendelton  with  care  wanted  reported  patients.  306 o u t p a t i e n t s  refused  treatment.  older  i n decisions,  the  of the p a t i e n t  has been  in  and l e t d o c t o r s  patients  i n personal  the  of  also  risky  Unfortunately,  their  participate  older  appear  differences  21% o f t h e s u b j e c t s  3% r e f u s e d  some e v i d e n c e  (1984) s t u d i e d  The s t u d y  in a later  on age  younger and o l d e r  to abdicate  Curley  doctors.  between  to  based  that  (1980) f o u n d  seeking  rate  (1984) .  patient  have not been e x p l o r e d  a 75% r e s p o n s e  for  though were  visiting  the p a t i e n t ) ,  l o w . Some o f t h i s  o f r e s p o n s e may h a v e b e e n due t o t h e o l d e r  the  ages  very  o f many  the patients.  13.0.  T h e Use o f P a t i e n t Identifying  patient  Preferences preferences  Over and  Time developing  a  utility  77 scale  for  consuming  patient  effort.  preferences Torrance state  are  identified  preferences  ficients  14.0.  of  Indications  on  This  the  was  treatment  are,  however,  Statistical  formal  that  i n repeated  same  that  demonstrated  by  a time  once  these  over  time.  measures o f  individual,  choices  high  health  remained  correlation  coef-  Analysis  design  and e n v i r o n m e n t a l  constraints  statistical  analysis  i n this  sample s i z e p r e v e n t e d  division  of subjects  with  per  enough s u b j e c t s  stratified  of  statistical  identify  cell  r e s u l t s was  First,  by f a c t o r s  meaningful  and t h e M a n t e i  significant  trends  was a s s e s s e d  using  how  observer  makes  two  underlying  A sensitivity  (Mantel, the  well  Chi  differences  frequencies,  measures  conducted  significance.  significant  responses  for  study.  l i m i t e d the use the small into  groups  m u l t i v a r i a t e or  analysis.  Analysis  account  was  (0.86 t o 0 . 9 4 ) .  Several  for  risks  they demonstrate s t a b i l i t y  e t . a l . (1982) f o u n d  consistent.  of  avoidance  two  chi  square  a number o f t e s t s  tests  were  between o b s e r v e d square  1963).  observers  observations. chance agreement  used  to  This that  test for  variability  ( S p i t z e r , 1967T.  agree  a n a l y s i s was p e r f o r m e d choices  was  used t o  and e x p e c t e d  Intra-observer  Kappa s t a t i s t i c  by s o r t i n g p a t i e n t  using  or  how w e l l  statistic  could  Kappa a single  takes  into  occur.  on s e v e r a l  by a p a t i e n t ' s  questionnaire past  experi-  78 ence  of  artery based  a  bypass on  h a v e on  using  on  risk  the  this  was  coronary  analysis  health  events  was  could  risk.  a v o i d a n c e between rule.  to  diagnostic.groups  The  illustrated  influence by  a  of  figure  life  rather  statistic.  15.0.  Conclusions The  present  study  treatment  outcomes  chapter.  Efforts  to  determine  employed were  the  made t o  reduce subject  and  interviewer  throughout  data  collection.  the  Methods s e l e c t e d i n making  choices.  argument  that  decisions  that  study  exposure  for  treatment  trapezoid  aversion  by  t h e s e major  towards  in risk  and  rationale  influence  attitudes  difference  measured  than a  The  possible  patient  expectancy  infarction  grafting.  the  The was  myocardial  involved The  subjects'  potential expressing  two  responses,  conclusions  drawn  errors a  the  patients  following  of  true  bias,  that  strategy  patients affect  described  and  directly  was  based  to  participate  length  and  q u a l i t y of  chapters analysis the  judgement preference.  condition  on  the in  their  responses,  could  Chapter  patients normative  health  care  lives.  The  only.  of  that  this  consistency  involved  the  analysis.  for  confidentiality,  describe the  in  maintain  ought  in stable  from  methods  preferences  ensure subject  were t h o s e  This  patient  study questions,  Chapter prevent four  a  the  and  clinical  three  explores  patient  evaluates  the  from  impact  79 of  independent  responses  to  variables  risk.  on  treatment  choices  and  patients'  80 CHAPTER THE 1.0.  STUDY OF  PATIENT PREFERENCES: E r r o r s  objectives  questionnaire study  pain  and  heart  used  the  need  disease.  other  of to  patient  previously  elicit  errors  (1983,  and  on  Tversky,  et.al.,  the  p.  need new  the  termed  a  One decision  of  the  598) to  makers  and  error  of  d o m i n a n c e , and  will  be  preferred  to  "preference invariance.  C.  by  coronary  i f several making  decisions  "the  in  i n which  Slovic  and  importance  decision-making  judgement  Thaler, that  utility  expected  i f alternative A  imposed  decision  on  1984;  Kahneman and  a  was  of  subjects."  of  judgement  of  first  in  Kahrieman  1980;  arises  theory  Tversky  has  order"  from also  a  been  theory  is  which  implies  Transistivity  Dominance  McNeil  (1979).  utility  is preferred  has  decision  L i c h t e n s t e i n , 1983;  Sinden,  expected  the  for  were r e a l .  errors  ( S l o v i c and  follow  in  research  of  by  therapy  to d e t e r m i n e  nonstudent  of  Knetsch  bias"  for  of  The  constraints  have r e c o g n i z e d  school  axioms of  development  in medical  death)  test  normative construct  s i t u a t i o n where  then A  An  "decision  transitivity,  choices  judgement  of  influence  1979;  1978).  violation  of  the  the  study sought  risk  making under u n c e r t a i n t y  a  Judgement  preferences.  under  were d e m o n s t r a t e d  A relatively focused  patient  t o make a c t u a l  ( i n c l u d i n g the  motivation  study guided  preferences  observed  Lichtenstein  this  Second, the  contexts  outcomes  and  of  Introduction Two  to  3  t o B,  describes  and  describes  that  B  the  to  C,  clear  81 preference  of  alternatives variations  or  one states.  in  an  1976) .  problem  i s presented,  sed  and  Invariance  chapter  and  reversal,  tency  choice  of  willingness reported most in  are  study  relative  value  when t h e s e  specific they  do  makers  outcome t h a t on  an  judgement  were: the  of  is discusThe  errors  framing,  consis-  asymmetric  choice,  of  effect.  The  studies  to subjects  were  the p a t i e n t q u e s t i o n n a i r e  by  theory  outcome o r  a  Risk  Aversion  probability  does  not  other  level  utility  occur  "certain" with  allow  t h i n g " to  proportionally  i s considered  value  the  "sure  any  Expected  outcome t h a t may  a decision  effect,  s t a t e s t h a t the  i s weighted  place  and  disease.  utility  This  (Keeny  certainty  questions  Example o f  outcomes w i t h  are weighted.  decision  an  outcome.  than  t h e way  described.  endowment  heart  choice  i n wording.  i t are  methods and  of expected  probability  to  e r r o r of  study  the  whose  theory  a high  refer  i n the development  the  small  effect),  The  of  c o n d i t i o n where  substitution  Certainty Effect:  occurrence  other  effect  and  outcome  o r more  formulation  The  o f an  when  the  of p a t i e n t s with  individual  with  to t e s t  one  affect  variations  this  (the  those  as  used  pay,  influential  the  2.0.  to  not  each p o t e n t i a l  tested in  preference  will  over  i s the  does not  such  the questions  described  state  Invariance  outcome  Raiffa,  In t h i s  alternative  of  theory  to of  an  "for  reasonable  the  event  h a v e more probability is violated  greater value or  an  sure"  on  a  than  82 probability.  For  e x a m p l e , when  chance of winning subjects value  1  choose (EV)  Kahneman  the  of  overweighting  of  have  when t h e McNeil  1976).  choice,  of  while  expected  value of  overshadowed  is this  certainty  the  higher  expected  ($320.00).  phenomenon  the  effect".  psychology  and  domination  in  with  expected  value  a  Pauker,  Raiffa  averse  clinical  patients.  has  also  they  an  $3,000  80%  choice the  probability found  These p a t i e n t s  very  bad  (Kahnemen  and  1976; 149)  the  Keeny  and  d e f i n e such  certainty  were  asked  chance of  (EV=$3,000) was  a  of  t o make a  sure. but  getting  by  with  McNeil  demonstrated  et.al. a  a  (EV= The  this  a high p r o b a b i l i t y associated  effect  $4,000  for  higher,  certainty  outcome w i t h  been  a  person".  When  i n f l u e n c e of an  (1976, p .  (1979) t e s t e d f o r  first  lower  and  1978;  chose  of  good  et.al.,  subjects.  the  very  i s t h e same  Tversky  the  a  value  risk  80%  by  outcome  cancer  "the  the s u b j e c t s chose  $3,200)  The  "a  student  20%  though  100%  $400.00, most  expected  Keeny and  maker as  95  even  call  a t a k i n g gamble on  Kahneman and using  of  choice  studies in cognitive  1979;  decision  chance  for sure,  or  c h o o s e between a  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  outcome even  Raiffa,  to  80%  (1979)  certainty,  r a t h e r than  Tversky,  an  alternative  Tversky  A number o f  sure  $300.00  the  and  medicine  $300.00 and  asked  was  $3,000. over  an  higher  (1978) i n  preference for  1 The expected value of an outcome is calculated by m u l t i p l y i n g t h e p r o b a b i l i t i e s and t h e v a l u e s o f e a c h component o f the outcome. An e x p e c t e d v a l u e i s i d e n t i f i e d i n t h e t e x t by t h e notation 'EV.  83 treatment though than  outcomes  the  (radiation) with  expected  for  the  survival  treatment  time  no  for  option  risk  of  these  t h a t had  early  death  even  was  less  patients  a risk  of  early  death  (surgery). Pauker, under  P a u k e r , and  conditions  This  study  included  counselling subjects  that  for  were  McNeil  (1981) s t u d i e d  carried 338  the  risk  prospective  possible  defects  parents'  of a negative  parents  in  outcome.  taking  unborn  choices  genetic  children.  These  asked:  "At what c h a n c e o f a pregnancy's producing a s e v e r e l y deformed c h i l d w o u l d you p r e f e r an e l e c t i v e a b o r t i o n t o t h e r i s k o f h a v i n g 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  deformed  child  abortion. with  The  by  state  the  that  would  encourage  distribution  numerous  influenced  to  peaks,  indicating values  toward  treatment  heart  study  years  of p a i n - f r e e l i f e  death  from In  by  of  that  as w e l l as risk  risk  t o have  an  of  was  wide  these  preferences  were  by  risk  a  levels  risk.  were e x p l o r e d  i n the  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  present level  of  a risk  of  p a t i e n t s were e x p e c t e d  to  t h a t compensated  for bearing  risk  avoidance  question  demonstrate a preference  for a  modest  modest  to  health state that  outcome  preferred  bearing  treatment.  the  between  of  them t o e l e c t  of a c c e p t a b l e  personal  Attitudes  level  perfect the  refers health  intermediate  a  and  complete  outcome, t h e y  outcome  for is  certain.  intermediate  disability. were a s k e d  A  If subjects to  determine  84 the compensation the  risk)  as  effect). asked to The  good  as  Patients  to s t a t e  make  needed  the  to  make t h e a l t e r n a t i v e  the who  modest did  t h e number o f  rejected  q u e s t i o n used  was  not  outcome select  additional  treatment  (with  the  the modest pain-free  certainty  outcome were months  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 d e s c r i b e d as  a treatment  (with  needed option.  choice.  L i s t e d b e l o w a r e two t r e a t m e n t s with different long term outcomes. These t r e a t m e n t s 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 t h e t r e a t m e n t you l i v e as l o n g as you e x p e c t t o l i v e , b u t you w i l l h a v e a n g i n a p a i n . t r e a t m e n t A: T h i s t r e a t m e n t c o m p l e t e l y e l i m i n a t e d a n g i n a p a i n f o r an a v e r a g e o f 6 y e a r s f o r 90% o f 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 . t r e a t m e n t B: T h i s t r e a t m e n t c o m p l e t e l y e l i m i n a t e d a n g i n a an a v e r a g e o f 5 y e a r s f o r a l l p a t i e n t s .  The was  based  'fair'  rationale on  to  the  Patients  that  treatment  who  treatment  asked had B  analysis  risk  outcome was  when  A  treatment  sensitivity  sensitivity  d e t e r m i n a t i o n of  patients  10%.  while  for a  and  known  had  how  much  t h e y were e x p o s e d f o r compensation an 5  expected years  a l l o w e d an the  analysis  'for sure'.  to a  value  risk  not  pain-free of  this  question  compensation  may  the of  seemed  of d e a t h  have  time  pain-free  e s t i m a t e of  positive  of  pain for  of  of  realized 5.4  time.  years This  n e g a t i v e v a l u e of a  treatment  whose  85  2.1.  Results of Questions In  (72%)  the  selected  subjects accept years to  the  the  not  effect  value one  Patients  should,  a preference physician, objective  of  the  to twenty  the  l e n g t h of being  life  offered  a  that  less  effective  treatment  the  in  to  of  4 more  good  health  risky  choice  additional of  These  needed  average  strong  i n f l u e n c e of  a b o v e a number  an  may,  the  t h a t many p a t i e n t s  certainty  t h e r e f o r e , be treatment  subjects  choice. the  the  64  'for sure'.  to p h y s i c i a n s  their  of  compensation  value  certain of  pain  f o r an  years  expected  out  of  of  other  being  alive.  o p p o r t u n i t y to  express  in  the  prolonging  view  life  i s to maximize the w e l f a r e ,  -  or  of if  the the  well-being  the p a t i e n t .  3.0.  Preference Slovic  "Preference  Lichtenstein  reversals  g a m b l e s , one  sum  o f money winning  Reversal  and  two  of  state  suggest  these  for be  of  should  angina  They asked  The  than  no  implications  the  values,  of  risk.  clinical  certainty do  10%  one  q u e s t i o n s , 46  to  treatment.  years, higher  The  with  asked  a range of  the C e r t a i n t y E f f e c t  effect  years  then  risky  with  5.4  five  were  accept  was  certainty  on  occur  featuring  when  p.  individuals  a high p r o b a b i l i t y  (the P b e t ) , the a large  (1983,  amount o f  other money  featuring (the  596) are  stated presented  of winning a  low  $ bet)."  that with  a modest  probability The  typical  86 finding  was  larger  monetary  values  that people  are  the  o f t e n chose  value  to  same.  the  $  the  axiom of p r e f e r e n c e  violated  "due  to  upon  1983,  p.  Lichtenstein  and  Slovic  (1971)  decision  was  a c h o i c e or whether  and  a price  pairs  of  bilities for  (or v a l u e )  Lichtenstein  of  and  a gamble a p p e a r e d  pattern viour  placed  large  while  of  their  by  race  frequently sum,  past  i n which  the  a gamble. 598)  and  losing",  track  may  model" i s  preferences  the  and  wins or  be in  patrons. on  losses.  information  later that  an  whether  a study  paper,  Slovic  "choices  among  by  to a  behaviour  of b e t t i n g beha-  showed shot  Kahneman  i s presented  probaoutcome  that  chance  patrons t o win  t o even-money b e t s  reversal  the  required  attractive  related  a long  the  bid.  Thaler  averse  that preference  on  way  s u b j e c t was  In a  whereas  (1985)  appeared  the  influenced primarily  also  bet  that  depending  observed  t o be  Thaler  they  choice  to encourage a higher  a small  have d e m o n s t r a t e d manner  p.  reversal  described among  on  appeared  winning  Preference  dent  (1983,  gambles  because i t  "preference  argued  information differed  set  interest  expected  597).  processed  to  the  a  considerations" (Slovic  subjects  simply  A  assigned  though  i s of  order.  processing  but  even  s t r o n g dependence of  information  Lichtenstein,  P bet  bet  This behavior  violates  the  the  can  and  Tversky  be  induced  to s u b j e c t s .  a  indepen(1982) by  the  87 The S l o v i c  and L i c h t e n s t e i n  choose between  and  (1971) s t u d y  asked  to b i d f o r the f o l l o w i n g p a i r s  s u b j e c t s to  o f gambles:  P a i r #1: 9/12 t o w i n $1.20 and 3/12 t o l o s e $.10; (P b e t ) P a i r #2: 3/12 t o w i n $9.20 and 9/12 t o l o s e $ 2 . 0 0 . ($ b e t ) EV f o r P a i r #1 = 0.875; EV f o r P a i r #2 = 0.70. Lichtenstein preferred subjects  and  the  Slovic  'P b e t *  set a higher  (1979) f o u n d  (1971)  to the  value  on  found  'dollar  choices of P bets  given  bets.  to  gambles asked  the  in to  following  $  The  the Grether bid  with  pairs  of  only  Grether  subjects 29% o f t h e and  Plott  motivated  by r e a l  money,  reversed  by t h e  prices  were  following  and P l o t t  real  bet'.  were  70% o f t h e i n i t i a l  63%  bet' while  the-'P  t h a t f o r s u b j e c t s who  that  i s one o f t h e p a i r s  (1979) s t u d y .  money f o r , and  Subjects  of  were  t o choose between,  the  o f gambles:  P a i r #1: 35/36 t o w i n $4.00 and 1/36 t o l o s e $1.00; (P b e t ) P a i r #2: 11/36 t o w i n $16.00 and 25/36 t o l o s e $1.50. ($ b e t ) EV f o r P a i r #1 = $3.97; EV f o r P a i r #2 = $3.85. Throughout bet'  is labelled  a short "gain  t h e q u e s t i o n n a i r e used  term  bet"  health and  improvement. because there the h e a r t  a "sure  no  refers  while  in  the  terminology  money b e t s  study,  the  to a high p r o b a b i l i t y '$  t o a low p r o b a b i l i t y  change  were  bet*  is  was  deemed  i n the questions  of  labelled  of a long-term  'P  a  health  necessary  developed  for  study.  The q u e s t i o n s in  improvement  refers  The  b e t " and  i n the present  the present  used  study  to i d e n t i f y  were  adapted  preference  from  research  reversal  behaviour  by S l o v i c  and  88 Lichtenstein Grether the  and P l o t t  preference  treatment graphic the  study  i n order  and  In asked  the p a t i e n t  used  a money  to  'bet'  of r e l i e f assist  and l o s i n g  real  weeks  of  of angina  of  a i d s f o r the  patients  t h e y would  study.)  were  be p r e p a r e d  outcomes s t a t e d  as  preferred  treatment  outcome  asked  (A o r B)  to  from  first  to stay  gambles:  B: 25% c h a n c e o f 8 y e a r s w i t h no a n g i n a p a i n , 75% c h a n c e o f p a i n t h e same a s i t i s now. (EV = 2 y e a r s w i t h no p a i n ) p a t i e n t s were  and  treatment  Outcome  the  The  Grether  A: 98% c h a n c e o f 2 y e a r s w i t h no a n g i n a p a i n , 2% c h a n c e o f p a i n t h e same as i t i s now. (EV = 2 y e a r s w i t h no p a i n )  i n the q u e s t i o n n a i r e ,  by  hospital  pain.  from  probabilities  questions,  the f o l l o w i n g  work  p a t i e n t s i n understanding  II f o r the v i s u a l  o f weeks  this  bet, patients i n  were a d a p t e d  represent  t h e number  of  Outcome  Later was  to  preference  to achieve  replication  asked  t o 'win' y e a r s  (see Appendix  hospital  a  Instead of  were  adjusted to  to state  from  (1979).  demonstrations  outcomes,  of  and  chances of winning  Plott  in  (1971)  state t h e same  which pair  gambles.  An order call  indifference  to reduce  o p t i o n was  included in  b i a s due t o what G r e t h e r  "systematic resolution  these questions i n  and P l o t t  of i n d i f f e r e n c e  (1983, p .  on t h e p a r t o f  626)  89 subjects occurs  forced to record a preference."  when s u b j e c t s who may  same o p t i o n  (e.g. they  really  always  Systematic  be i n d i f f e r e n t  choose  'A')  resolution  choose the  every  time  they  feel  indi fferent. To 100%  identify  and 98% c h a n c e o f t r e a t m e n t  patients of  how much p a t i e n t s v a l u e d  one  who  chose Treatment  year  with  success,  no a n g i n a  pain  changing  a choice.  h e / s h e was o f f e r e d 11  more  months.  subjects  The  overvalued  compared  This  was d e m o n s t r a t e d  less  than  pain. 15  by  Many r e s p o n d e n t s  chance of  patients  and  subjects  t o change,  months up t o  t h a t p a t i e n t s and h e a l t h y one y e a r with  subjects  free  satisfied  with  a  of angina  no a n g i n a  pain.  a c c e p t i n g much  v a l u e o f a 98% c h a n c e o f 2 y e a r s appeared  There  free  from  100% c h a n c e o f  o r 18 m o n t h s .  angina  who  were asked  angina.  selected  at  The s e n s i t i v i t y  the subject's  chance o f 8 y e a r s " 5 years"  t h e 25% c h a n c e o f e i g h t y e a r s  t o c o n s i d e r a 50% c h a n c e o f f i v e analysis  a l l o w i n g the p r o b a b i l i t y  vary  of  showed  A.  healthy  plus additional  98% c h a n c e o f two y e a r s  the expected  Patients  by  to a  p a t i e n t s and  asked  a 100% c h a n c e  i n s t e a d of Treatment  year  results  t h e 100%  pain  choosing  When t h e s u b j e c t d i d n o t a g r e e  the o r i g i n a l  between  the questionnaire  A to consider  was c o n s i d e r a b l e r e s i s t a n c e among to  the d i f f e r e n c e  of  of the  discretion.  i s two y e a r s  i s 2.5 y e a r s .  while  T h o s e who  this  years  q u e s t i o n was  with  no  with  no  conducted  "50% c h a n c e  of 5  years" to  The e x p e c t e d  value  o f a "25%  the expected chose  value  o f "50%  t h e 50% c h a n c e o f f i v e  90 years  may  have  understanding the  "25%  (years) was  The  the  Those  exploration  were a l s o  In  this  able  to  outcomes, s u b j e c t s actually  preference  study  the  i n the  Table  hospital  were  permitted  the  results  'A' and 'B', a s t h e y  in  left  the  cell  reversal cell.  in  (called  table,  on i t s  to b i d the  to choose although  asking  They  between o n l y one  demonstration  for  ' b e t s ' on a  fora l l subjects. are i n  Preference while  The  the questions.  reversal the  an i n c o n s i s t e n t c h o i c e )  Throughout  presence,  treatments.  When a s k e d  of  indifference.  a s *A=B'.  right  of i t s  indifference  f o r both  r e l a x e d by  i s identified  upper  the understanding  indifference,  Indifference  preference  of  s u b j e c t s were  state  summarizes  are labelled  analysis  o f S l o v i c and  d i d . Constraints of the o r i g n i a l  3.1  the lower  on t h e outcome  Questions  makes t o  b i d 'no w e e k s * .  reversal  to choose  sensitivity  the hypothesis  influence  study,  could  to focus  a demonstration  non-money gamble, a n d by a l l o w i n g  the  who c o n t i n u e d  This  Reversal  this  of  may h a v e had an  above.  i s not j u s t  same number o f weeks  choices  50%, o r t h e y  probability.  of Preference  reversal  appearance.  of  value.  (1983) s t a t e d  contribution  preference  subject  the  s t r a t e g y f o r demonstrating  Results  an  on  c h a n c e o f 8 y e a r s " were assumed  Lichtenstein  but  of expected  r a t h e r than  the  3.1.  anchored  appears  opposite of appears i n  a l l d i a g n o s t i c groups,  the high  91 probability of  the  Table  outcome  i s p r e f e r r e d , as  shown  i n the  left  for a l l Subjects,  n-64  hand  cells  table.  3.1  Preference  Reversal  choice  note: A B 3.2.  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%)  represents represents  of  64  results  (17%)  counterbalanced pattern  between of  when  An the  these asked  between t h e he  bet bet  preferred  from a l l s u b j e c t s  exhibited preference by  opposite  choice".  all  sure gain  Discussion When t h e  out  the the  A<B  four subjects to p r e f e r e n c e  additional  reversal.  (6%)  subjects  c h o i c e s when t h e y  b i d weeks  to  identified  choose  one.  o p t i o n s when he * A'  had  when b i d d i n g .  who  reversal,  14  subjects  were t a b u l a t e d ,  were  in hospital  to choose  finding  is  t e r m e d an " i n c o n s i s t e n t (22%)  one  11  exhibited a decision  a preference Only  This  only  indifferent f o r them,  between the  s u b j e c t was between  but  options  indifferent  them,  although  92 The the  results  high  probability  'A' when for  of these  asked  to  questions  outcome.  diagnostic  most s i m i l a r  heart  control  exhibited disease those  preference  controls  angina  pain  the  largest proportion  rence  that  could  When a s k e d angina the  seemed  patients  bypass  'A' o r  realistic in this  stated  a 98%  chance of  that  both  t h e b i d and  pain  relief  long  as t h e i r  35%  This  their  about  their no more  choosing focus  only  was an a t t r a c t i v e expected  the  received  an e i g h t  lifetime.  occur-  size. severe  One-half of artery  t h e b i d and t h e  'certain'  that  with  and a c t u a l l y  a coronary  on b o t h  because  Among  and none o f  patients with  patients  gain  heart  two g r o u p s had  for,  Those  said  while time.  future health.  A>B  (n=15)  7% o f p a t i e n t s  sample  of  and t h e  subjects  reversal  choices,  was on t h e  pain.  the choice  subjects  was an u n a n t i c i p a t e d  their  bids  patterns  time,  of  bidding  g r o u p had a l r e a d y  Patients  choice  the  h a v e b e e n due t o t h e s m a l l about  the  (n=14) d i d . T h e s e  'B'.  (66%) c h o s e  1 week t o 52 w e e k s ) .  preference  angina  toward  the i n i t i a l  healthy  of  i t  of s u b j e c t s  to talk  graft.  The  and d i s a b i l i t y ,  severe  either  (from  20%  (n=15) d e m o n s t r a t e d  patients with  although  the healthy  patients.  a trend  42 s u b j e c t s  compared,  between  reversal  the  choosing,  were  (n=20) e x h i b i t e d  patients with  mild  dispersed  groups  r e s p o n s e were disease  In a l l ,  choose a treatment,  'A' and *B' w e r e w i d e l y When  demonstrated  q u a l i t i e s of  choosing year  i t would  B>A on  period of  likely  be a s  93 Several who  healthy  demonstrated  making a  relief,  high  probability  were  reminded  of  Framing: Research  demonstrated because  "A  the  ...  by  McNeil  e t . al.(1982)  years  merely  of  life  a l . (1982) u s e d  424  radiologists  subjects  could the  for  "mortality  a  framing has  'A'  with  These  the  subjects  available  of  framing  the  under  graduate test.  potential  to  (1984, p .  16)  occurs alter  a  suggest  made by  the  contingencies."  the  of  effects treatment and  i n an  students is  framing  The  as  study  ambulatory i n business  the  with  outcomes:  second,  treatment.  Here  have  o u t c o m e s and  mortality,  male p a t i e n t s  making  This bias  the d e c i s i o n  d e s c r i p t i o n s of  491  decision  bias.  influence  after  of  Tversky  demonstrated  238  and  frame".  fields  framing  survival  et.  to b i d  i f i t didn't  take  not  for  Effect  a question  percent  of  because  was  reasons  were w i l l i n g  relief.  position  patients  question.  s c e n a r i o s and  i n terms of  *B'  pain  Kahneman and  patient  described their that they  with  i n f l u e n c e of  ...  disease control  subsequently  studies in several  physician  first,  years  Formulation  response.  different  would  fall-back  the wording of  subject's that  The  reversal  f o r treatment  two  the  heart  stating  they  that a  c o n s t r a i n t s of  4.0.  choice  in hospital  provide pain  the  preference  treatment  more weeks  s u b j e c t s and  question  average  by  McNeil  setting, school  as  from  the  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 t r e a t m e n t , 32 w i l l h a v e d i e d by 1 y e a r , and 66 w i l l h a v e d i e d by 5 years. Of 100 people having radiation therapy, none will d i e during t r e a t m e n t , 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 years. Which t r e a t m e n t would you p r e f e r ? The  alternative  "survival surgery  frame", offered  radiation Radiation and  way  asked an  offered was  cancer  of  an  that  this  subjects  to  choose  life  average 42%  in  life  violate  (1984,  invariance  treatment  (years of elected  when  o f 6.1 y e a r s and of  4.7 y e a r s .  i n the m o r t a l i t y life)  frame,  frame.  The  surgery.  No l u n g  described  framing  study.  p . 343) h a v e as  a  expectancy  cases  in this  question, c a l l e d the  expectancy  of t h e time  both  participated  Kahneman and T v e r s k y questions  of  i n the survival  subjects  patients  framing  average  preferred  25% o f t h e t i m e  majority  of  follows:  I m a g i n e t h a t t h e U.S. i s p r e p a r i n g f o r t h e o u t b r e a k o f an u n u s u a l Asian d i s e a s e , which i s expected to k i l l 600 people. Two a l t e r n a t i v e programs t o combat the disease h a v e been p r o p o s e d . Assume t h a t t h e e x a c t s c i e n t i f i c e s t i m a t e s o f t h e c o n s e q u e n c e s o f the programs a r e : P r o b l e m 1: (152 s u b j e c t s ) I f P r o g r a m A i s a d o p t e d , 200 p e o p l e w i l l I f Program 600 p e o p l e people w i l l  be s a v e d .  [72% chose  A]  B i s adopted, there i s a one-third p r o b a b i l i t y that w i l l be s a v e d and a two-thirds p r o b a b i l i t y t h a t no be s a v e d . [28% c h o s e B]  ..The same c o v e r 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 t h e p r o s p e c t s a s s o c i a t e d w i t h t h e two p r o g r a m s : P r o b l e m 2 (155 s u b j e c t s ) : I f P r o g r a m C i s a d o p t e d 400 p e o p l e w i l l  d e s c r i p t i o n of  d i e . [22% chose  C]  I f Program D i s adopted, t h e r e is a one-third probability n o b o d y 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 p e o p l e die. [ 7 8 % c h o s e D]  that will  95 Several strating terms  that  could  these  induce  reported techniques  McNeil  particular  terms.  et.al. fear  The r e a s o n  (1978)  to  outcomes  preferred  were  treatment. possible,  altering  encouraged  described  used  f o r both  formulation variation treatment.  as  the  c o u l d cause  were n o t u s e d  with kept  by  The  may  even an as  from  have a  and a l l o w  behaviour  patient  outcome.  were  c h a n g e was drawn  radiation  were  medical  patients  patients  the question implied  their  i f the  unidentified similar  as  Patients  were  using visual  aids  same v i s u a l  a i d was  (see Appendix I I ) .  f o r such  a  simple  question  was  test  of  the  to determine  subjects to a l t e r  The f r a m i n g q u e s t i o n s were a s  (a) The " w e l l n e s s  in  o n l y t h e o r d e r of t h e outcomes.  questions  of  the  questions  the treatment  reason  such  that  avoidance  by  the  t o s e e what  that  The  generate  Second,  for this  o f demon-  First,  and a n g i o p l a s t y  finding  of treatment  preconceptions  study.  preconceptions  The w o r d s s u r g e r y , d r u g s ,  identifying  the  from  f r a m i n g were made i n t h e p r e s e n t  avoided. as  departures  their  effect  of the  whether  a small  preferences  fora  follows:  frame".  After a t r e a t m e n t f o r a n g i n a , some p a t i e n t s h a v e no p a i n w h i l e some p a t i e n t s h a v e p a i n t w i c e a s o f t e n a s before the treatment. The numbers below a r e chances t h a t t h e t r e a t m e n t w i l l e l i m i n a t e angina pain f o r 2 years. Which o f t h e s e groups would be a c c e p t a b l e t o you?  96 chance of A. 90% B. 70% C. 50% D. 30% E. 10% If A would If  E  (b)  no  pain 10% 30% 50% 70% 90%  i s not a good be a c c e p t a b l e ?  The  "illness  often  'chance' f o r  lower  chance  yes  /  no  i m p r o v e m e n t , what  i s not  chance  acceptable?  frame".  pain  Framing  twice  his/her  choice  as  often  no p a i n 90% 70% 50% 30% 10%  considered of  a  present  treatment  i s , i f a more c o n s e r v a t i v e  preferred  in  the  "illness"  Subjects  were  question  did  considered  "wellness"  frame),  be  to  influence present  by  one  be  was  the  /  no  patient  level  in either  was  chosen  level  A was  considered  to  c o n s i s t e n t i f the  their if  when  treatment  f r a m e and  framing  considered not  to  yes  Effects  F r a m i n g was  the  as  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 t w i c e as as b e f o r e the t r e a t m e n t , w h i l e some p a t i e n t s h a v e no more The numbers b e l o w a r e c h a n c e s t h a t t h e t r e a t m e n t w i l l c a u s e twice as o f t e n f o r some p a t i e n t s . Which of these groups be a c c e p t a b l e t o you?  chance of A. 10% B. 30% C. 50% D. 70% E . 90%  That  twice  enough  i s a c c e p t a b l e , what  After often pain. pain would  4.1.  pain  the  choice. illness  changed  direction.  (level  B  was  preferred in be  present.  framing  Framing  of  was  frame caused  a  the also less  97 conservative permitted  choice  "good  and  to extend  an  additional  by  the  (offered range  from  other  alternatives  Table  treatment of  framing  3.2.  stating  that  probability  of  Framing  Effects  framing more less  f o r A l l Heart  same  4  8  15  heart  9  3  8  20  6  3  6  15  6  5  3  14  24  15  25  64  Note:  would  stating be  with they  they  offered  by  as  good heart  allowed  reached  a  determined  subjects  two  control  angina angina  Study  S u b j e c t s , n=64  total  3  TOTAL  until  of p a i n r e l i e f ,  healthy  severe  because  treatment  only.  diagnos i s / outcome  mild  that  also  improvement),  of p a t i e n t s  studies  have  no  offered  relief  treatments  studies  S u b j e c t s were  outcomes  pain  probabilities Other  frame.  i n the study  to continue choosing  patient.  by  a high  probability  of u n a c c e p t a b l e  the  of  q u e s t i o n s used  differ  patients level  enough"  The  disease  the w e l l n e s s  to a v o i d making a c h o i c e  was  enough.  than  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 t o t a k e any t r e a t m e n t .  98 4.3.  D i s c u s s i o n of Framing Table  3.2  vulnerability with  an  accepted  shows  to framing:  "illness a less  A detailed  "I  take  can't In  subjects of  4.4.  decide  treatment  a "wellness under  treatment  frame" w h i l e  15  t h e same c o n d i t i o n s .  here  p a t i e n t s made comments  my  I don't  r e p o r t s of  found  conservative  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  doctor  w a n t e d me  like:  to take."  "I Or,  h a v e any a d v i c e . "  studies  c o n s t r a i n e d by  probing  two c h o i c e s  the  framing  bias,  and e v a l u a t i o n o f some  c o u l d n o t be made.  D i s c u s s i o n o f D i a g n o s t i c Groups appeared  similar  extent.  framing  effects.  (60%) mild  exhibited angina  of  14  power  to  Seven  (79%)  patients  15  a l l diagnostic  framing  were  while i t .  nine  patients,  p a t i e n t s o u t o f 15  For p a t i e n t s with  i n f l u e n c e d by t h e f r a m i n g  were n o t s t a t i s t i c a l l y  with  groups  to a  (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  Among h e a r t d i s e a s e c o n t r o l  to detect a d i f f e r e n c e The  affect  of  demonstrated  These d i f f e r e n c e s  the  more  with  that these  because  previous  Framing  out  a  c o n s e r v a t i v e treatment  whichever  the e f f e c t s  o u t o f 64 p a t i e n t s d e m o n s t r a t e d  took  than  e v a l u a t i o n of  were  39  24  frame"  m a k i n g a c h o i c e showed would  that  was  severe  12 o f 20 (60%) w i t h angina,  11  of the q u e s t i o n .  significant  although  the  low.  t h e most s e r i o u s p a i n and d i s a b i l i t y  g r o u p most v u l n e r a b l e t o t h e d e c i s i o n  bias.  were  Of c o n s i d e r a b l e  99 interest  was  appeared  t h e number  not  subjects, patients  to  eight who  consistent  be of  o f p a t i e n t s who  influenced 15  were h e a r t  members.  (53%)  two  (14%) were c o n s i s t e n t .  were  i n f l u e n c e d by f r a m i n g . with  decision  severe bias  pain  more  Among  consistent.  with  of those  only  this  were  Patients  c o n s i s t e n t and  framing.  disease controls  members c o n s i s t e n t w h i l e  patients  by  remained  had  mild  The g r o u p o f  seven  angina  of  i t was  difficult  (35%)  s i x o f 15  severe  The m a j o r i t y o f t h i s  Again,  20  had  14 p a t i e n t s w i t h  healthy  angina,  last  group  t o deny t h a t  and d i s a b i l i t y were n o t i n f l u e n c e d by than  healthy  or  only  moderately i l l  persons.  4.4.  Conclusions The  to  of the framing  demonstrate  effects the  focus  of  format  framing  alone,  the formulation used  a  induced  to change t h e i r  severe  number  40%  drawn  r e s e a r c h was n o t  but to demonstrate  other p e r i p h e r a l  of a q u e s t i o n .  varied  that  effects.  than  clinical from  with  significance  the  fact  that  of  of the q u e s t i o n  f o r a treatment 20%?  Only  outcome  wording  'illness  (with of the  framing'  framing'.  this  almost  whose  one p a t i e n t  by t h e  outcome w i t h  'wellness  p o s s i b l e with  p a t i e n t s and s u b j e c t s be  so s t r o n g l y i n f l u e n c e d  t h a t he c h o s e a t r e a t m e n t  I t was  the wording  Would  preference  by more  above the treatment The  is  of  a n g i n a ) was  question  in this  to demonstrate  caused  probabilities  questions  demonstration  twice  of  framing  a s many s u b j e c t s were  100 vulnerable had  a  framing  visual  improved Further the  to  health  or  understanding  The The  choice  into last  of  (A)  of  in preference  both  the risk  to  preferences  for  the  to  illness  anchor  says  would  on  of  either  improve  the  communication.  theory choice  equally should  states that (B), then  not  if  death  as  present  study  effect  held  an  of  any  change  i n f l u e n c e the  choice  attempted for  outcome.  The  the McNeil  p a t i e n t s with  by  of  and a 5%  the  cancer  an risk  outcome of  to  determine  clinical  decisions  first  et.al.  of  the  added  to both  other  outcomes  (pain r e l i e f ,  level  i n order  to maintain  The  actual  with  death.  substitution  s e t s of  one  B.  replication  death  influence  of  frame.  question  (1978)  lung.  study  Heart  To  effect,  outcomes w h i l e or  the  results  no  t r y to a  10%  pain  risk  change)  to  90%  of  probability  rounded  to  the  of of  of  no  reduction  demonstrate  simultaneously  total were  greater  was  disease  were o f f e r e d a c h o i c e b e t w e e n a m o d e r a t e outcome w i t h  accompanied  100%.  probabilities  patients  utility  to a second  i n the  of  a  risk  how  a barrier  substitution  essentially  patients  f r a m e and  physician  axiom of  choices  questions  involving  as  is preferred  affects  whether  a  the  also  Substitution Effect  substitution  Two  identifying thing  These s u b j e c t s  representing  the w e l l n e s s  framing  that A  were c o n s i s t e n t .  clearly  i n both  research  first  5.0.  aid  as  the  death  was  reducing  the  their  former  outcomes  nearest  5%,  at to  101 reduce  subject confusion.  problems with substitution sets  efforts  first pair given  effect  in its strictest  o f two  were o f f e r e d  sets.  pair  predicts  that  of c h o i c e s ,  of choices  (Savage,  sense.  to  The r e a s o n  t o make t h e d e c i s i o n  Theory  small p r o b a b i l i t i e s  can cause  t h e f o r m u l a t i o n o f an a c c u r a t e d e m o n s t r a t i o n  of p r o b a b i l i t i e s  common u s e  Rounding  a  f o r this  1954).  rather  than t h e  c h o i c e was due t o  treatment  treatment  The two  three  as p o s s i b l e .  choosing  should choose  In a d d i t i o n ,  subjects,  as r e a l i s t i c person  1  of the  series  A  i n the  A* i n t h e s e c o n d of  choices are  below.  Substitution  effect,  p a r t one:  Listed below a r e some hypothetical b e n e f i t s l i s t e d ; w h i c h one w o u l d you cannot have both t r e a t m e n t s .  treatment treatment  choice:  A  A B  no a n g i n a 80% 60%  or B  p r o c e d u r e s w i t h r i s k s and choose? Assume t h a t you  same p a i n 15% 40%  risk 5% 0%  of death  o r no p r e f e r e n c e  I f y o u c h o s e A, what o u t c o m e s w o u l d much t o e n c o u r a g e y o u t o c h o o s e B?  need  t o be a l t e r e d  and by how  I f y o u c h o s e B, what o u t c o m e s w o u l d much t o e n c o u r a g e y o u t o c h o o s e A?  need  t o be a l t e r e d  and by how  1 The r o u n d i n g o f t h e p r o b a b i l i t i e s i n t h i s example c a u s e d the u t i l i t i e s o f t h e outcomes i n t h e examples chosen t o v a r y by .05. Clinical significance and p a t i e n t understanding 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 Substitution  effect,  These treatment you choose? treatment treatment choice: What  state  those  the  first  death  pair  o u t c o m e s , w h i c h one w o u l d  same p a i n 15% 35%  which  outcome  Treatment  swing  their  was  risk  the likely  probably  have  omitted. felt  A is a fairly  A  significant  (risk  the  B*.  presence  Some  influence  by p a t i e n t s  who  pair  of  select  of choices patients to  the c e r t a i n t y choice B  close  approximation  of  the s t a t i s t i c a l  s u r g e r y a s r e p o r t e d i n t h e CASS S t u d y  Option B i s a close  medical  therapy f o r coronary a r t e r y disease. these  since  zero.  of  healthy  the r i s k of  I n t h e q u e s t i o n n a i r e , t h e A*  1.  from  of  encouraging  Chapter  data  attraction  averse patients) i n  in  The  of the choice of  o p t i o n s of t h e second  A to  h e r e was  of bypass  while  asking the patient  determinant  the pain r e l i e f ,  c h o i c e from  of death  Option outcome  choice, i n both  B* m a r k i n g s were  effect  was  B would  t h e f o c u s onto  of d e a t h  choice?  f o l l o w e d by  subjects choosing treatment treatment  risk 15% 10%  o r no p r e f e r e n c e  o f c h o i c e s was  a s an outcome  alter  the  different  o r B*  second  for  and  have  no a n g i n a 70% 55%  A*  treatment.  may  groups  two  a s p e c t s d i d y o u f o c u s on t o make y o u r  The to  A* B*  part  approximation  q u e s t i o n s were a n a l y s e d  s u b j e c t s f o r whom t h e d e c i s i o n  of  reviewed  t h e outcome  i n two  groups:  was h y p o t h e t i c a l , and  103 patients Those fied  subjects in  Subjects the  with heart  a  B.  Patients  (in  terms  it.  This  a modest  Table  free  analysis  3.3.  cell  employed  was  f o r patients  also  used  had b e e n  f irst  notes:  diagonal.  are identified i n table. analysis  to  treatment  t r e a t m e n t A needed  t o be  f o r them t o c h o o s e  t o i d e n t i f y whether t o assuming  a  there  'risk'  was  after  chosen.  E f f e c t : A l l Respondents, second  are i d e n t i -  who s e l e c t e d  i n order  among p a t i e n t s  'for sure'  axiom  sensitivity  how much b e t t e r  Substitution  choice  a  realistic.  on t h e main  o f each  f r o m symptoms)  resistance  outcome  left  was  their choices  substitution  point  were a s k e d  o f time  considerable  the  question  tradeoff  in  and t h e B,B* c e l l s  i n the lower  second  determine  cells  violated  B,A* c e l l s The  f o r whom t h e d e c i s i o n  who were c o n s i s t e n t  t h e A,A* who  disease,  n=100  choice  A*  B*  A  47  8  B  # 19  26  (a)percents e q u a l c o u n t s when c o u n t e q u a l s 100. (b) # i d e n t i f i e s v i o l a t i o n o f t h e s u b s t i t u t i o n a x i o m (c) Kappa o f .44 i n d i c a t e s p o o r i n t r a s u b j e c t a g r e e m e n t .  104 Table  3.4. S u b s t i t u t i o n E f f e c t :  Heart Disease Groups,  second  choice  notes:  Table  choice  A*  first  # identifies  B*  A  29 (59 .2%)  B  #13 (20 .6%)  violation  n=49  1 (2.0%)  12(19.0%)  of the s u b s t i t u t i o n axiom  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 and H o s p i t a l A d m i n i s t r a t o r s , second  Subjects n=51  choice  A*  B*  A  18 (34 .6%)  7 (13.5%)  B  # 9 ( 1 7 .3%)  first  choice  note:  5.1.  # identifies  violation  o f t h e s u b s t i t u t i o n axiom.  Discussion It  is  interesting to  note that  more c o n s i s t e n t l y r i s k - s e e k i n g and  17 (32.7%)  hospital administrators.  same r a t e o f v i o l a t i o n patients, making  and  17% f o r  a consistent  of  than  disease  the group  patients  of healthy  were  adults  Both groups demonstrated almost the  the  substitution  the healthy  choice  heart  were  subjects.  compared  by  axiom:  21%  f o rthe  When t h e s u b j e c t s health  s t a t u s , no  105 significant and  heart  d i f f e r e n c e (p=.64) was  found  healthy  direction of  s u b j e c t s made an  to v i o l a t i o n  the p a t i e n t s with Comments responses.  heart  disease  outcome was  of  A*,  was  comments  and  B and  they  distracted  on  by  both  Some  they  T h e s e comments  of  risk  death  interest  claimed  explained on  pain  from s u b j e c t s support t o make  risk  of  the  risk  the  choices  that  chose A  of  chose to  (10%  and were  death  t o make  be was  levels of  and  death  death  a s s e r t i o n of by  Analysis  a x i o m seemed risk  the  second  when t h e y  two  i n order  with  suggests  these  when  relief  the  when t h e y  in avoiding  that  in  patients  a  2%  of  because  unacceptable."  substitution  that  A*  exclusively  having  only  patient  question  choose  and  of  opposite  understanding  from a  first  was  i n the  14%  choice.  to the  exclusively  the  treatments  focused  not  subjects  risk  (1974) t h a t s u b j e c t s t e n d attributes.  of  violated  patients They  could  that  axiom, w h i l e  response  i n the  relief  so when t h e i r  added  verbal  level  pain  focused  "similar". similar,  on  T h o s e who  drawn t o do  group  I  healthy  focused  B*.  15%).  the  of  substitution  chose A  b e t t e r , but  g r o u p s was  d i s e a s e made t h i s  this  "I  these  inconsistent choice  the  A typical  because  subjects  of  heart  from  these  question  subjects  disease patients.  A n o t i c e a b l e d i f f e r e n c e between the  between h e a l t h y  a  was  choice.  MacCrimmon  comparing  pairs  of  106 6.0.  Asymmetric Utility  study, final the  theory  health) state  of  474)  trait  do  is  determined  h e a l t h , not  maker  not  may  is  decision  always  be  the  value  by  the  support  "risk  of wealth  final  the p a r t i c u l a r of the  t a k i n g may  v e r y dependent  in." maker  by  i n t h e Domain o f G a i n s  Observations  states that  but  Choices  states that  individual.  behaviour p.  Choice:  Therefore,  in a situation  life  theory.  on  be  the  (or i n  this  in  risk  of  decision  making  MacCrimmon  (1974,  situation  facing  or  circumstance  a general  actually which  Losses  asset position,  actual  not  or  a  personality the  loss  decision  may  place  taking behaviour  a is  demonstrated. An been  alternative  called  hypothesis changes  value of for  In  a  loss  associated  studies losses. observed This the  other  (1980,  words, The  gains, than  p.  42)  has  f o l l o w s : "...  f o r losses while  generalization f o l l o w i n g two  the  One  observation that  reference point  a gain  are  the  more  determine  intense  f o r the the  aversion from  findings  treated  Kahneman and  feelings  of  the  differently risk  i s observed  a number o f  steeper  same m a g n i t u d e .  small p r o b a b i l i t i e s ,  from  1979).  f u n c t i o n appears  gains  risk  has  utility  summarized  i s drawn  examples  Tversky,  choice  makers h a v e a s u b j e c t i v e  with  very  risky  decision  describing  loss  for  addresses  some a r b i t r a r y  a  Except  understanding  (Kahneman and  theory  a gain.  than with  as  from  or  for  theory'  prospect  i n wealth  losses  Thaler  'prospect of  decisions.  proposal  than  seeking  is  for gains."  results  Tversky  above  including  (1979).  107 Both  examples o f f e r  identical  final  states  P r o b l e m 1: In a d d i t i o n to whatever $1,000. You a r e now a s k e d t o c h o o s e A: B:  a 50% c h a n c e o f $500 f o r s u r e  In t h i s p r o b l e m , c h o s e B.  70  s u b j e c t s were  a 50% c h a n c e o f l o s i n g l o s i n g $500 f o r s u r e .  In t h i s p r o b l e m , c h o s e D.  To or  test  whether  patients  68  whether  the  c o u l d cause  The  questions  subjective health  present in  study asset  different used  in  given  chose  you own, you between:  A  and  have been  84%  given  tested;  69%  chose  position were position  were asked  more t o make  over  either  study  to t e s t  C  and  31%  behaviour, important, treatment gains  or  behaviour. the  heart  losses  in  relation  to  patient's states  of  below.  (a) C h o o s i n g b e t w e e n g a i n s . Choose between the f o l l o w i n g treatment exercise, treatment  16%  theory described choice  asset  v a l u e of gains or  a r e s e t out  have been  $1,000  utility in  c h o i c e s where c h a n g e s losses  you own you between:  tested;  s u b j e c t s were  changes  in  wealth.  $1,000  P r o b l e m 2: In a d d i t i o n to whatever $2,000. You a r e now a s k e d t o c h o o s e C: 0:  of  two  treatments:  A: A 50% c h a n c e o f no a n g i n a p a i n a f t e r any amount o f and a 50% c h a n c e o f p a i n t h e same as i t i s now; B: T w i c e as much e x e r c i s e f o r s u r e w i t h no a n g i n a p a i n .  108 (b) C h o o s i n g b e t w e e n l o s s e s . C h o o s e b e t w e e n t h e f o l l o w i n g two  treatments.  treatment exercise,  a n g i n a p a i n a f t e r any amount o f being a b l e to e x e r c i s e at a l l ;  A: A 50% and a 50%  chance o f no chance of not  t r e a t m e n t B: A c e r t a i n b e f o r e angina p a i n the Patients How How  were a l s o  study  choice  similar  states  that  in  improving status  quo  subjects study  demonstrate  than  would  the  Tversky  gamble p o s e d  loss  loss  of  a  theory  gain i n the  or  tests  not  was  study  the  theory  biased  theory  by  of  the  (1979)  loss.  Should  losses,  utility  were r i s k  was  (and  Tversky  a  of  a  prefer a  the  theory  seeking  n e c e s s a r i l y be  heart of  but  domain of  If subjects would  This  50/50 c h a n c e  demonstration  i n the  i n the  question  Kahneman and  a  eliciting  theory.  gains  from a  aversion  theory.  50/50 gamble  The  of  outcome f o r s u r e  domain of  i n the  chance  suggest  prospect  the  (as  risk  domain, p r o s p e c t  because  the  loss  in prospect  i n the  losses.  t o a 50/50  results  rather  a  i n favour  p r e f e r a modest  'gamble' o f or  time  angina pain? angina?  biased  described  averse)  domain of  the  questions),  than  to those  were  subjects w i l l  the  current exercise  asked:  questions  therefore risk  risk  this  1/2 o f y o u r i t i s now.  l o n g c a n you e x e r c i s e now b e f o r e many b l o c k s c a n you w a l k w i t h o u t  The  are  l o s s of same as  in  supported  somewhat b e t t e r by  Kahneman  and  (1979).  Patients consecutive  and  healthy  c h o i c e s , one  subjects  replicating  were the  asked  domain of  to gains  make and  two the  109 other  replicating  the  losses.  of  subjects  were  one-half  hour.  and  some p a t i e n t s , n o n e x i s t a n t .  influence of  on  asked  to  For  very  the  patients with The  the  choices  In T a b l e s the  number o f  number each  i s the  cell.  Table  3.6.  of  This  factor  responses  first  the  c h o i c e s made on  the  'lossbid'  3.6  and  3.7,  the  question  first  and  the  total  column  Choice  number  combined  totals  are  f o r A l l Heart  B' total  total  found  minimal,  h a v e had i n the  an  group  were r e p r e s e n t e d the  second  listed  by  question  A  5 10.2%  9 18.4%  14 28.6%  B  9 18.4%  26 53.1%  35 71.5%  14 28.6%  35 71.5%  49 100.0%  i n each  choice.  number o f  lossbid  gainbid  may  was  of  columns.  s u b j e c t s making the  A'  healthy  exercise tolerance  the  by  Asymmetric  of  while  angina.  made i n  totals  symptoms  level  unique p a t t e r n of severe  A l l p a t i e n t s were  i l l p a t i e n t s , e x e r c i s e time  p r o p o r t i o n of Row  level  imagine a  ' g a i n b i d ' rows, w h i l e  were r e p r e s e n t e d  is  current  of  reminded  for  their  domain  The  cell  second  s u b j e c t s found  in  labelled.  Study  P a t i e n t s , n=49  110 Table  3.7. A s y m m e t r i c  Choice  f o r A l l Healthy  Subjects,  n=51  lossbid A'  B' total  A  14 27.5%  8 15.7%  22 43.2%  B  15 29.4%  14 27.5%  29 56.9%  29 56.9%  22 43.2%  51 100.0%  gainbid  total  6.1.  Discussion Across  on  a l l  the f i r s t  averse.  choice  When a  B,B' c h o i c e ) disease,  risk  while  would  The  significant  subjects  subjects  were  43%  be e x p e c t e d  found relating  Three  averse  with  from  very  First,  choices (the  patients  to a loss  prospect this  risk  with  heart  different  situation,  57% were  risk-seeking, less  of the theory  situation.  same  nature.  i s t h e 57% o f In  fact,  40%  questions.  interesting  t h e upper  were  t o be s i g n i f i c a n t l y  a money q u e s t i o n  departure  i n both  and  64%,  averse  o f t h e s u b j e c t s were  who a r e r i s k - a v e r s e i n  were r i s k  data.  healthy  groups  than  the majority,  c o m p a r i s o n was made o f r i s k  On t h e q u e s t i o n  averse  36% o f s u b j e c t s were r i s k - s e e k i n g  (gains), while  among  the  (p=.016).  100 s u b j e c t s ,  trends  right-hand  cell  were  e s t a b l i s h e d i n these  o f each  table  presents  Ill the  responses  theory. cell and  The  have  responded  predicted.  in  the gain  in  mild  the heart angina  severe  n=14), o n l y  posed  decision  strategies  half the  a s many v e r y pattern  asymmetric young,  istics  with  especially The  ces.  This  Tables this  3.6  that  subjects  that  choice and  is  has  choice pattern while  and t h e  in  (those  to  the  disability  subjects  theory. been  with  conducted  other  initial  influence Less  than  demonstrated  Previous  bets.  theory  the loss  as p r e d i c t e d by p r o s p e c t support  money  finding  r e s e a r c h on primarily  The  heart  demographic  on  study  character-  may n o t be g e n e r a l i z a b l e  i s that a d i f f e r e n t  p a t i e n t s were r i s k  displayed  3.7.  pattern  are hypothetical.  interesting  s u b j e c t s and  (n=20)  i l l patients  as h e a l t h y  the accepted  question  the  e r r o r s o f judgement.  using  used  in  choice  p a i n and  prospect  behaviour  this  Of t h e h e a l t h y  controls  some  - including  i f choices  second  healthy  study  by  20% made a r i s k - a v e r s e c h o i c e  subjects demonstrating  suggests  responded  t h e 14 v e r y  i l l patients  choice  question.  14% r e s p o n d e d  p r e d i c t e d by  healthy  evidence  of  by t h e  represented  risk-seeking  offers  prospect  way t o t h e f i r s t  disease  a  of  evidence  question  averse  (n=15),  and  However,  This  and p a t i e n t s  one-third  question.  theory.  a s p r e d i c t e d by  way t o t h e s e c o n d  question  angina,  questions  a risk  (n=15),  In both  with  two  subjects  seeking  subjects  patients  the  healthy  in a risk  adult  to  in  averse  t h e lower  Among h e a l t h y 53% o f h e a r t  per cent  on b o t h  right-hand  choi-  cell in  s u b j e c t s , 28% d e m o n s t r a t e d disease  patients exhibited  112 it.  The  third  patients  are  choices. while  interesting the  This  the  group  other  (healthy  and  most  angina),  To  understand  pattern,  an  a n a l y s i s of  conducted.  A  choose the  50/50 gamble  is  now  short  Similar tion. able  to  pain." the on  patient  that  reasons One  e x e r c i s e at choice  groups  was  question  this  by  time  the  time  at  a l l (heart disease  con-  severe  processes  angina  in question  twice  apparent "I  a l l for that risk  healthy  (a)  nothing  glad  chance of  created  the  seeking  c h o i c e by  the  biggest  complete  subjects.  This  the  to  "I  was  would  exercise  really  on  this  question  commented:  for choices  a 50%  this  still  be  of  underlying  b e c a u s e my  is  would  7%  of  both  the  p a t i e n t ' s comments on  ( a ) . I t i s almost  demonstrated  not  ill  over  outcome 29%  outcomes o n l y  thought  with  were  risk-seeking  risky  or  the  patient replied:  The  the  groups chose these mild  i s t h a t t h e most s e v e r e l y  consistently chose  trols) .  so  finding  time  nothing."  second  risk  ques-  not  freedom  being  from  this  d i f f e r e n c e between  severely reverse  ill  of  patients  the  pattern  i s a t r e n d worth f u r t h e r  investigation.  6.2.  Conclusions The  hospital the Only  data  collected  administrators  observations 24%  domain of  from  of gains  of  a l l and  the  in this  asymmetric  heart  study  seeking  study  did  c h o i c e as  respondents risk  64  (n=100) i n the  not  i t has  s u b j e c t s and strongly been  were r i s k domain of  36  support  described.  averse  in  the  losses.  At  113 least risk  half  of  averse over  this  pattern.  modest good  every  group except  both  choices;  The  heart  outcome f o r s u r e and  a  very  20% o f a d m i n i s t r a t o r s  study  rather  poor  hospital administrators  patients  were  demonstrated  generally  preferred  t h a n a 50/50 gamble b e t w e e n a  outcome  or a very  good  a  very  outcome and t h e  s t a t u s quo. The gains  exception  and  choices  losses  status  by  may h a v e  experienced  to t h i s  general  patients  been  with  by p a t i e n t s  with  Further  because  i t  discussion  patients  appears  Physicians  is  and  on  other  patient that  patients.  Although  were t h e most patient  7.0.  applying  strategies  have  pain  even t h e i s a poor  and d i s a b i l i t y . of  professionals choice  can best  the very  t h e most s e r i o u s l y i l l risk-seeking,  treating  ill  those  meet t h e needs  s i m i l a r to those  risk-seeking  g r o u p s was n o t s t a t i s t i c a l l y  Efforts  question)  behaviour  strategies  differentiate  consistently  Willingness  first  current  health  of  described  and d i s a b i l i t y  4.  who must make a t r e a t m e n t by  pain  over  Risk-seeking  F o r many p a t i e n t s ,  seeking  patients the  the  i n the  of the r i s k  i n Chapter  by  angina.  based  seeking  severe angina.  encouraged  quo ( a s i t i s d e s c r i b e d  outcome  f i n d i n g was r i s k  and  patients the  just  risk-averse in this  difference  study  between  significant.  t o Pay been  to understand  made the  by value  economists to  to  adapt  consumers o f  market  health  care  114 consumption at  the  in  point  stated  that  reduce  risks  have  of  service delivery.  " i n a market  application to-pay'  a s i t u a t i o n where t h e r e  that of  these e f f o r t s  for health  been  paid  care  to  the  valuations  of  by  may  be  is  c o n s u m e r s may  that  health  care  therefore, doctor's) not  exist  they  is  not  value  Problems with that  "valuations  life  appears  to  this the  best  dependent  of  the  health  not  individual's l i f e  an  Generally, of  income o r  net  to  uni-dimensional  a  One  services insurance.  1984, least  what and  of  the  p.  255).  of  which  how  much  Consumption, (usually  for care  also 1984,  short do  to h i s / h e r  a means o f  face."  the  which  may  patient.  are  and  willingness-to-pay w o r t h as  the  to  "individual  1984).  need  has  more  value  agent's  (Evans,  that  the  of  the  575)  'willingness-  the  the  patient  pay  exploring  (Evans,  care  are  to  public  judges of  on  p.  not  (Evans,  patient's  linear"  have l e s s v a l u e  or  of  the  when t h o s e  measure, not  consume  of  do  a measure of  death"  t h e s e measures value  they  private  willingness-to-pay are  people  been a measure of  as  of  be  should  usually  the  risks  a technique  with  determination  reflect  has  viewed  probabilities  problems  expect  than  either  consumer o r  Several  we  to  (1983,  services, especially  for  Willingness-to-pay service  face  cost  Mendeloff  context  t h e y do  i s no  due p.  to  fact  A  long  256).  one.  not  the  take  family  measures u t i l i z e e s t a b l i s h i n g the  In  addition,  into and a  account friends.  proportion value  of  a  115 health  care  service.3  asking  what  people  questions  asking  answers.  ought  people  The p r e s e n t  method t o  Medeloff  t r y to  (1983)  to  pay  what  they  study  for  a  will  has a d o p t e d  q u a n t i f y how  cautions  that  health  program and  pay l e a d  the l a t t e r  much p a t i e n t s  questions  to  different  strategy  value a  as a  treatment  program. Thompson arthritis a very  et.  al.  patients  low r e s p o n s e  rate  (27%)  to  patients  posed  researchers  suspected  patients  offer  only  to  that  findings  that  the  seemed personal framing  with less  pain  than  patient to  be  concept  affected  because  disability.  by  s u c h as  interviewer  may  issue  to  the  what income.  technique  First,  of  d i f f i c u l t one  al.  (1984)  limited They  were  more  statistical  'fair'  that  i n f l u e n c e d by study  willingness-to-pay  seemed  could  concluded  The a r t h r i t i s  In  in  a r t h r i t i s . The  be a  Thompson e t .  severe a r t h r i t i s by  chronic  of r e g r e s s i o n s .  responses  variables and  this  the w i l l i n g n e s s - t o - p a y  with  Second,  s i g n i f i c a n c e of the r e s u l t s  arthritic  explored  a p p l i e d to  this  grasp.  tentative  many p a t i e n t s  have  a n d i d e n t i f i e d a number o f c o n s t r a i n t s .  questions  for  (1984)  rather  found  measure than by  a d d i t i o n , problems  impaired the  with  v a l i d i t y of the  questionnaire. Berwick willing  to  and W e i n s t e i n pay f o r  just  for its role  found  3 Other research i n Acton (1973,  (1985)  diagnostic  reported  that  patients  i n f o r m a t i o n f o r i t s own s a k e ,  i n medical d e c i s i o n making.  on t h e v a l u e o f h e a l t h 1976).  Sixty-two  care  services  were not  patients  may be  116 in  this  about  the  majority and  study  were  status  of  of  their  in this  sound d i a g n o s i s  during  wealthy p a t i e n t s per  patient  to  Tversky  asked  to  ment. the  nearly  and  effect  on  skewing  of  know w h e t h e r normal.  the  baby was  to  eligible  keep t h e  found  behaviour.  In  selling  the  asked  their  selling  p r i c e was  for  For ultra-  of  the  level  with  four  very  t o pay  from  $430  transactions Tversky  willing  income  study  p r i c e f o r a gamble  were a l s o  normal  gender  that  average w i l l i n g n e s s  The  withheld.  willingness-to-pay,  explored  fetus.  T h e y were a l s o  Weinstein  has  lowest  the  women  of  information  their  50%  (1967)  g a m b l e . The  that  information  patient.  Subjects  items of  to have  $709 p e r  state a  seven  pregnancy wished  Berwick  willingness-to-pay  and  to  h e a l t h was  study,  significant  value  health  wished  own  baby a s u r p r i s e . a  to  i n some c i r c u m s t a n c e s ,  example,  had  their  patients  whether  to pay,  asked  similar subjects i n an  maximum b u y i n g  u s u a l l y higher  to were  experi-  price  than  the  for  buying  price. The avoided by  patient the  asking  heart  problems of  patients  money f o r for  one  to  year  surgery.  i s s u e would of  preference  be  should  not  be  In  biased  this and  value. by  a  per  retirement  resolved  similar relative  monetary  trade of  questionnaire  way,  in  the  present  trade-offs for health cent  of  f o r an  i t was  a l l patients Evans argued  a  services  reasonable  altered waiting  hoped could  that  of  status  fairness  a  commodity  trade  they  sum  the  (1984) t h a t  i n d i v i d u a l wealth while  study  valuations maintain  117 an  individual  approach.  for  this  question,  to  pay  was  retirement  used.  of  period.  percent This  a  5%  chance  the  a n a l y s i s of  results  sum  the  p a t i e n t was  willing  the  of  offered having  P a t i e n t s were a s k e d  to  pay  f o r e l i m i n a t i n g the  day.  the  reduced  p a t i e n t s were  pay  1  of  in  bias  of  l a r g e and  small  'needs*.  Initially, out"  the  Therefore,  get  rid  The  ess-to-pay  of  the  5%  risk  risk  following three and  hypothetical  compensation  waiting  how  list  the  a heart  much  f o r 3 months, questions  for  attack  they  (gamble).  demanded  opportunity over  would  be  to a  "buy  6 month  willing  to  P a t i e n t s were a s k e d  to  5 months,  evaluated  and  patient  f o r changing  a l l but  willingn-  p o s i t i o n s on  a  treatment:  To d e t e r m i n e how many d o l l a r s you how much money you need f o r 1 y e a r your a n n u a l income. Income = $  have f o r t h i s q u e s t i o n , s t a t e of r e t i r e m e n t , and make t h a t  You a r e on a 6 month waiting l i s t for heart surgery. If other p o s i t i o n s on t h e l i s t were a v a i l a b l e , how much o f y o u r income f o r one year would you be willing 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 w a i t t h e r e i s a 5% c h a n c e you c o u l d have a heart attack. To  wait  only  3 months  To  wait  only  1 month I w o u l d  To  not  wait  at  I w o u l d pay pay  a l l I w o u l d pay  $ $  $  118  7.1.  Results Table  prepared  Table  of W i l l i n g n e s s  3.8  summarizes  t o pay  to  to  the  r e d u c e a 5%  Pay  number risk  of of  subjects a heart  who  were  attack.  3.8.  Willingness  to  Pay  time  for A l l Patients  frame:  and  3 mo.  Healthy  Subjects,  5mo.  a l l but  1  n=64  day  number who would not pay:  20  13  8  number who w o u l d pay (%  44 (39.9%)  51 (46.1%)  56 (56.2%)  7.2.  income)  Discussion Subjects  reducing  the  eliminated pay  to  refused  sooner  were  risk  a  than  5%  5%  risk  a  This  process  they  how  over be  for  were  attack  later.  a period similar  when t h e  bear  only  thought one  willing  to  day of to  f o r three  until  about  be  refused  to  months  risk,  not  months m i g h t Tversky's  a  likely affect  (1974)  for  could  tomorrow.  this  would  pay  risk  More s u b j e c t s  would last  they  risk  may  study  heart  would  a  them, w h i l e thought  of  risk  asked  that  present  rather a  when t h e  was  the  risk  reduce  patients reply  in  than When  typical affect them.  119 finding while  7.3.  that  subjects  underestimating large  study  probabilities  ones.  with previous studies produced  no  a patient. prefer  The  30%  treatment  data  treatment  would  did  not  reduce feel  the  i n the  8.0.  Endowment  Thaler describe  be  when s u b j e c t s  goods  not  they  when  reducing  However,  anything  significant  to take  or  can  risk)  a  12%  treatment  because  they  to  patients  between  of a h e a r t a t t a c k , e i t h e r  of  the  term  people The  are asked  to  had  they little  they  compensation  demanded by  have  not  i n order  who  effect'  part  with  things  effect  appears  to s t a t e and  been  (1985) d e m o n s t r a t e d renters  'endowment  endowment  already possess  McNeil  accept  technique  a trend that  later.  pay  already possess.  Kahneman and  they would  indicated  than  was  reluctance  rights  (as a method o f  introduced  they  goods o r  this  present  Effect  positions) strong  that  the  treatment.  (1980)  the  risk risk  confidence  The  rather  would  the  evidence  certainly  sooner  of p a t i e n t s  that  of w i l l i n g n e s s - t o - p a y ,  conclusive  measure t h e v a l u e of  same  to overestimate small  Conclusions As  and  tend  selling  buying  prices  prices  owned b e f o r e . this  effect  were a s k e d  t o move t o a n o t h e r  what  to (or to for  f o r the Knetsch,  i n a study  of  compensation  apartment.  For  an  120 average  rent  $1,000.00 In their  the  proxy  for  would  The  be  renters  asked  f o r compensations  of  $10,000.00. patient preference  list.  'endowed*.  the  $443.00,  willingness  waiting  for  to  of  The  the  to  'sell*  compensation  value  I f the  of  the  study, top  the  a p o s i t i o n when t h e  p a t i e n t s were  positions  demanded  for a  position  endowment e f f e c t  l a r g e r than  heart  was  top  that  a  hypothetical  p o s i t i o n was  had  already  in operation,  p r i c e a p a t i e n t would  p a t i e n t was  on  told  he  was  asked  this  be  willing  on  the  a  been value  to  pay  bottom  of  list. questions  were as  follows:  You a r e 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 t h e l i s t . You h a v e already waited 6 months. Waiting l o n g e r has a 5% c h a n c e t h a t you c o u l d h a v e 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 t o e v e r y o n e on t h e l i s t as is available f o r you. No one i s s i c k e r t h a n y o u . Would you g i v e up y o u r p l a c e t o w a i t 1 more week? How much c o m p e n s a t i o n w o u l d you want? $  w o u l d you g i v e up y o u r p l a c e t o w a i t 3 more m o n t h s ? How much c o m p e n s a t i o n w o u l d you w a n t ? $ Would you g i v e up y o u r p l a c e t o w a i t 6 more m o n t h s ? How much c o m p e n s a t i o n w o u l d you want? $  8.1.  Results Subjects  of  the  were  Endowment expected  Effect  t o ask  Questions  f o r more c o m p e n s a t i o n  to  sell  121 what was to  v i e w e d as a p o s i t i v e s t a t e  acquire  relinquish  i t . a  attack.  place  on  give  were  p o s i t i o n that  heart  indicates  They  list  they  also  expected  would  expose  V e r y few s u b j e c t s  the waiting  than  for  were w i l l i n g to  them t o  were w i l l i n g a n y amount  t h e c o m p e n s a t i o n demanded  be  by t h o s e  r e l u c t a n t to the r i s k  to give  o f money. who  t o pay  were  up  of a first  Table  3.9  willing  to  up t h e i r p o s i t i o n .  Table  3.9.  Compensation  Demanded,  n=64  give  up one week  53 s u b j e c t s (83%) w o u l d n o t s e l l o r trade their p o s i t i o n s . 11 s u b j e c t s w o u l d g i v e them up f o r 38% more i n c o m e .  give  up t h r e e  58 s u b j e c t s (91%) w o u l d n o t s e l l o r trade their p o s i t i o n s . 6 s u b j e c t s w o u l d g i v e them up f o r 57% more i n c o m e .  give  up s i x months  notes: stated  months  60 s u b j e c t s (94%) w o u l d n o t s e l l o r trade their p o s i t i o n s . 4 s u b j e c t s w o u l d g i v e them up f o r 53% more i n c o m e .  ( i ) Compensation i s l i s t e d as an a d d i t i o n a l p e r c e n t o f a a n n u a l income. ( i i ) F o r s u b j e c t s who w o u l d not accept compensation, the r e s e a r c h e r c o n f i r m e d w i t h e a c h s u b j e c t t h a t e v e n 100% more income w o u l d n o t e n c o u r a g e t h e p a t i e n t t o r e l e n q u i s h t h e p o s i t i o n on t h e waiting l i s t . Most subjects said t h e y w o u l d n o t g i v e up t h e i r p o s i t i o n s f o r a n y amount o f money.  122 When of  i t came t o c o m p e n s a t i o n  64, o r 83%) o f p a t i e n t s w o u l d  take  on  a  position  5%  risk  of  on t h e w a i t i n g  a  wanted  were w i l l i n g  t o pay t o a v o i d  among  patients  compensation  from  the w a i t i n g  list.  5%  risk  annual to  another  Those  Patient  to take  angina,  of  patient risk,  his #3  annual  wanting  they  he  an  while  to accept  a lower  12% o f  an a d d i t i o n a l  than  they  Patient  to accept  p o s i t i o n on  to get r i d of a  additional  6%  #2 a l s o  he w a n t e d such  to take  i t . F o r example,  t h r e e were w i l l i n g  wanted  t o pay  up t h e i r t o p  a risk  #1, w o u l d p a y n o t h i n g  income  i n return  had  (53 o u t money t o  agreed  accept  on t h e same r i s k .  was w i l l i n g  sum o f  who  to accept  p a y t o g e t r i d o f t h e 5% r i s k ,  100%  few  money t o  patient  any  a t t a c k by g i v i n g  i t once  mild  f o r 3 months, b u t income  heart  much more  with  not accept  list.  compensation  demanded, t h e m a j o r i t y  of h i s refused  an a d d i t i o n a l  a risk.  h i s income  Similarly, to avoid the  75% o f h i s income t o t a k e  it. Again, with  patients  willing these  t h e most  to  noticeable difference  who had  pay t o  patients  reduce  were asked  response  was: " I w a i t e d  risk  of  a heart  risk  (a 5% r i s k )  h a v e had in  Chapter  risk,  especially  f o r 3 months  i s worth  5%.  for  feelings  3 months.  t o pay, a  f o r my b y p a s s w i t h  I don't  v e r y much."  occured  T h i s g r o u p was t h e l e a s t  why t h e y d i d n ' t want  a t t a c k than  some n e g a t i v e 4.  severe angina.  between groups  typical  a greater  think eliminating  These  When  p a t i e n t s may  that also  towards h e a r t s u r g e r y , as noted  However, t h e y were t h e l e a s t  willing  to  g i v e up a  123 position  on  the  established the  risk  waiting  across  many p a t i e n t s  to  the  prevented  number o f to  the  8.2.  well  as  healthy  position.  health  endowment  the  pay  tomorrow.  100% The  of  i n the  pay  to  was  pay  their  constraints  could  they would  trend  as  i s i n t e r e s t i n g to  said  a l l they  income of  the  although  f  a  in  addition  patients  question.  studies  than  and  present  study  that  a t t r i b u t e greater  value  to  and  to wait than  its  can  be  this so  influence  counselled or  when a  i f other  expected.  one  aware  with can  strong.  t o be  of  relating  fully  the  treatment  health  are  a  to  examined  of  patients  force  such  understood.  chosen  system.  i l l u m i n a t e the  be  strength  decisions,  lists  a position  acquire  should  circumstances  Waiting the  are  on  to  questions  demanded  preferences are  t o pay  on  compensation  frustration  s u c h as  willing  choices  professionals effect,  i n the  they are  i f patient  longer  sentiment  data  Subjects'  patient  public  the  subjects  more e f f e c t i v e l y  to wait of  It  100%  c u r r e n t l y hold  simultaneously  be  willingness  them f r o m o f f e r i n g more t h a n  i s c l e a r from  willingness-to-pay  If  to  A clear  Conclusions  they a  patients  i t .  certainty.  were w i l l i n g  eliminated  income a l l o w e d  It as  risk  t h e y had  in increased  approaches  note t h a t  question  once  a l l groups  reduction  have  list  may  requires  the  common  patient source  Findings  r e a s o n s why  the  from  public  124 9.0.  Summary o f F i n d i n g s This  which  chapter  the study  based.  from  previous  preference  study  The  and c o m p e n s a t i o n  demonstrated  purpose  has been  chapter  of independent of  the  degree of d i s a b i l i t y , determine chapter  and  improved  making by a  of  by  judgement  were  the  certainty  substitution  choice  in  health  effect, effect,  Fewer s u b j e c t s i n i n t h e domain o f  other  studies  of this  used.  on  questions  exploring  the  subjects'  choices.  The  such  variables  previous  treatment  o f judgement  as p a t i e n t ' s a g e , history,  was t o  demonstrated  in this  i n some g r o u p s o f p a t i e n t s .  sensitivity  o f judgement.  upon  of  demanded.  presents  the errors  were compounded  decision  errors  whether  were  foundations  have s u p p l i e d e v i d e n c e t o  the  found  variables  analysis  errors  asymmetric  b i a s when money b e t s following  influence  to  of  framing,  and l o s s e s than  judgement  the research  s u b j e c t responses  reversal,  present  gains  relating  demonstrations  willingness-to-pay, the  presented  questions  Data  support  has  Cooperative  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 toward  patients  most  vulnerable to  125 CHAPTER  MEDICAL DECISION  MAKING: P a t i e n t  Characteristics,  1.0  and  s t u d y of  the  Quality  attempted  care  p o l i c y is addressing  treatment  among  considerable ageing  of  (Evans,  the  of  (1984,  the  of  Demographic  Life  Issues.  The  patients  with  substantially  persons  groups  has  been  of  on  have  the  on  needs  for  funding  years  stated  i t i s that changing, relative  of  that  in  utilization  of  drawn  f o r p a r t i c u l a r types  to  the  of  care  due  to  the  the  increasing population.  actual  as  to  for  ageing  cessation  rates  increase  elderly."  actual preferences or  i n Canada  utilization  way  the  utilization  i n the the  for  example,  care  around  specific a  patterns For  health  age)  such  health  influence that  i t i s not  "age-sex  disease  current  patients.  centred  65  issues  heart  preference  has  p.309) has  been  the  focused  will  e l d e r l y (over  the  some o f  debate  greater  themselves  of  identifying  population  population,  attention  by  a t t e n t i o n has  and  proportion  illuminate  specific  1984).  patterns  Evans  to  preferences  has  are  Preferences,  Introduction This  of  4  Limited of  of  older heroic  interventions. The  approach the  of  variables  to  selected  were  hospital  experience.  the  patients'  diagnosis,  study  has  treatment age,  been to  link  choices.  previous  health  independent  The  variables  history,  and  126 The asking  influence  patients  required  some  some r i s k  of  of  to  express  death  directly  these  patients  were w i l l i n g  averseness  of  f o r m and  summarize  patient  are  each  one  the  and  healthy  discussed.  Data when  treatment.  The  the  are  and  this,  Three  the  life  the  risk  is displayed  also  treatment  investment  health.  years,  subjects  that bear  as  Following  by  to  future  five  explored  patient  with  own  year,  patient.  choices  asked  was  f o r outcomes  presented  t o make i n t h e i r  patients  graphical  or  associated  questions  by  choices  preferences  morbidity,  were e x p l o r e d :  expected  patient  their  of  of  years  on  period  results  time p e r i o d s  angina  presented  carried  no  in  that  risk  of  age  on  death. Two  questions  guided  treatment  choices.  different  preferences  second,  are  judgement  these  discussion  of  of  coronary  three  for  did  older  of  new  other  of  angina  data  more  on  on  on  age  choice  of 65  have  patients?  prone  to  And  errors  of  patients? older  v a r i a b l e s : the  g r a f t i n g on  choice  over  regarding  independent  infarctions  in Future  emphasis  of  influence  than younger  patients  analysis  the  patients  treatment  a r t e r y bypass  Investment A  the  myocardial  influence  2.0  First,  analysis  i n d e c i s i o n making than younger  Following  previous  the  patterns, choice  patients  is a  influence the  patterns,  of  influence and  the  patterns.  Health  preventive  health  s t r a t e g i e s and  lifestyle  127 modification  motivated  willingness  to  questions future  invest  asked  how  consumption,  health without pants  indicated  spend  in  a number o f q u e s t i o n s in much where  symptoms  future  subjects  now  younger p a t i e n t s  and  relate  to  question  offered  t o them, o l d e r s u b j e c t s and  years  of  this  when  a  d i d not  address.  Patients with  arrythmia  the  outcomes w i t h  The  following  willingness  question  angina was  relief  this  or valve  pain  i t  to  partici-  Although  difficult  question  less  to  some  o f good h e a l t h  to was  than t e n  difficult  to  d i s e a s e were o f f e r e d  r e p l a c e d by  used  as good  be p r e p a r e d  patients with  find  study  t o spend f o r  The  later.  found  'your  symptoms'.  determine  patients'  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 questions you have 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 later. while i n the h o s p i t a l . To a) b) c)  would  lifetime  The  described  disease.  they  subjects  life  same  expected  healthy  was  heart  o f weeks f o r pain  health.  were p r e p a r e d  consumption  of coronary  t h e number  the h o s p i t a l  their  to explore patients'  to t r a d e weeks i n t h e You will have p a i n  completely e l i m i n a t e angina p a i n : f o r 1 y e a r , I would spend weeks i n t h e h o s p i t a l . f o r 5 y e a r s , I would spend weeks i n t h e h o s p i t a l . t o e l i m i n a t e p a i n f o r t h e r e s t o f my l i f e , I w o u l d s p e n d weeks i n t h e h o s p i t a l .  What  would  you be g i v i n g  up t o s p e n d  these  weeks  i n the h o s p i t a l ?  128 Table standard of  4.1  summarizes  deviation  of each  investments.  "Investment relating spend  The  in  the  to achieve  group  graphic  Future  number  the findings  time  without  of  t h e group.  diagnostic  g r o u p was c a l c u l a t e d  statements  of t h e i r  life  4.1 I n v e s t m e n t  GROUP  to indicate  indicates patient  symptoms,  The a v e r a g e using  the group  to  life the  in  F i g u r e 4.1,  was w i l l i n g t o  the  average  patients'  subjective  expectancy.  i n F u t u r e H e a l t h by P a t i e n t  Groups  (number o f weeks b i d ) p e r c e i ved 5 years life l i f e expectancy (in years)  M SD Med.  2.7 2.0 3.0  10.3 11.8 8.0  21.5 24.4 10.0  33.7 13.2 35.0  other heart  M SD Med.  6.1 11.2 2.5  13.1 22.6 4.0  28.7 28.1 24.0  19.5 11.5 15.0  angina mild  M SD Med.  3.7 5.9 2.0  8.7 13.3 4.0  20.4 25.6 12.0  18.7 8.8 20.0  angina severe  M SD Med.  6.6 13.4 2.0  13.9 25.3 5.5  31.1 38.8 10.0  13.1 6.9 12.5  SD=standard  deviation;  life  expectancy f o r each  healthy  M=mean;  t h e range  importance o f  TIME PERIOD 1 year  Notes:  group, w i t h t h e  representation  weeks e a c h  expectancy  Table  included  Health",  of  from each  Med.=median  Figure  4.1.  130 4.1  Discussion Healthy  future  subjects  h e a l t h when t h e  g r o u p b i d an  average  good h e a l t h . those  had  The  with  hospital  to  I t was  seriously  i l l  investment  of  2.7  forms  f o r a year  health.  least  weeks  of  of  was  also  31  to  ensure  interesting  weeks  healthy  i n the h o s p i t a l s u b j e c t s b i d 21  Several be  prepared  they  should  patients  that  patients to stay  less  one  they  year had  that,  than  half  the  an  no  invest  year  years  of  52  to weeks angina  u p p e r bound t o f o c u s on  stated  would pain.  of  though  that  their  preference be  an  When  tolerance  a personally  the  average life  they doctor  h e a l t h outcome.  a  good  of  of  while  good h e a l t h .  l o n g as  state  of  o n e - t h i r d more  weeks f o r 33  a good  and  expectancy  of expected  as  weeks  of  angina  years  groups  year  severe  f o r o n l y 13  to a c h i e v e  if  to  This  i n the  even  life  in  weeks  T h e s e p a t i e n t s b i d an  i n the h o s p i t a l  with  t h e y were p r e p a r e d time.  life.  encouraged  asked  f o r one  weeks f o r one note  invest  stay.  b i d 3.7  to  i n the study  i n order  were  interviewer achieve  pain free  hospital  Patients with  t h e h e a l t h y s u b j e c t s , t h e y were p r e p a r e d time  to  h e a r t d i s e a s e b i d 6.1  t h e m o s t : 6.6  p a t i e n t s had  a  m i l d angina  good h e a l t h .  invest  willingness  i n the h o s p i t a l  patients with  other  were p r e p a r e d  the  would said These  when  the  acceptable stay patients  to  realized  for a hospital  stay  a c c e p t a b l e l e n g t h of  131 2.2.  Conclusions The  belief  results  of  the  in  these  physicians  whose stated  study.  These  physicians  willing  to alter  lifestyle  had In  recently  that  t h e momentum o f  approach  of  medical  behaviour  as n o t e d  education  and  health  patients  i n the  were t h e most  as s m o k i n g  when  heart a t t a c k or severe anagina  seemed most w i l l i n g ill.  the 'curative'  care  in  participated  such  a t a t i m e when h e / s h e was most  explain  questions supported the  patients  behaviours  experienced a  o t h e r words, a p a t i e n t  health  investment  most  Chapter  rather  It may  also  often  pain.  i n future  This finding  prevalent  1.  promotion  to invest  they  helps to  than 'preventive'  in  some  explains  appear  physician why  to f a l l  health on d e a f  ears.  3.0  Value The  of Risk  risk  different  Avoidance  avoidance  degrees  to the r i s k  patients  with  pain  continuing develop  Arrow  associated  coronary heart  relief pain  a utility  tested  whether  of d i s a b i l i t y demonstrated  aversion  of  questions  accompanied with  no  with  patients  different  treatment.  In  with  amounts o f the case of  disease, the r e l a t i v e  desirability  by  compared  risk  treatment formed  the  risk  trade-offs  to  used t o  function.1  1 A comprehensive d i s c u s s i o n of (1958, 1963, 1965, 1967, 1971)  utilities  may  be f o u n d i n  132 Chapter  2  included a  (1978) o f  using  scale  describe risk  to  Pauker  of  Quality  was  angina  and  bypass  one  asked  of  the  with  "determined by  the  by  1976,  Pauker  incorporating quality using only  ability  l e n g t h of  as  offered  to speak  questions  used  cancer  life  on  a  patients. by  analysis  and  quality  or  suffering  n e c e s s i t a t e d by  p.8).  absence  In  a  of  life  life.  a longer  was  Subjects or  life  radiation  utility  of  of of  two  life.  disabling coronary  subsequent  (1981) d e m o n s t r a t e d  et.al.  Earlier,  presence  that a  study, utiltiy  d i s p l a c e d downward in this  radiation expectancy  study  were  for laryngeal at  the  expense  offered  shorter  survival  patients'  utility  for  intact.  in determining  were d e v e l o p e d  of M c N e i l  points  functions  for surgery  to speak w h i l e  the a b i l i t y  avoidance  the  p a i n and  (Pauker,  Surgery  The  equivalents  utility  to g i v e p r e f e r e n c e s  cancer.  t h e method  aversion for  W e s c h e l b a u m and  function  of  p r e f e r e n c e : q u a n t i t y of  surgery"  McNeil,  from  certainty  (1976) d e v e l o p e d  dimensions  review  from  the  three  studies described  risk  above.  T h e y were as f o l l o w s :  For t h i s q u e s t i o n use t h e number o f y e a r s you e x p e c t t o l i v e as the years f r e e of angina p a i n . S t a t e how many y e a r s o f l i f e you would take (with angina like you have now) i n o r d e r t o 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 complete recovery yes  to from no  take your  a p i l l t h a t o f f e r e d a 98% h e a r t d i s e a s e and a 2% r i s k  chance of of death?  133 Would heart  you a g r e e t o e x c h a n g e a l l t h e y e a r s you e x p e c t d i s e a s e f o r one y e a r o f p e r f e c t h e a l t h ? yes  pill?  yes y e a r s of  life  no for  Take t h e p i l l ? yes Take years of  life  no for  Take the p i l l ? yes Take y e a r s of  q u e s t i o n was  25%  chance of  subject, asked In  and  offer? helped  treatment  the  years  words,  Was  administered empty  pill  failure.  he/she  subjects  probabilities  of  f o r sure  would  the  indifferent deal  outcomes.  with  a 50% lifetime  chance of and a 50%  that has f o r your  a 75% lifetime  chance of and a 25%  that has f o r your  a 25% lifetime  chance of and a 75%  with  a s s i s t a n c e of  sure.  the  c a p s u l e s , each Indifference  f o r e a c h answer o f f e r e d  whether  other  no l i f e for  coloured,  that has f o r your  sure.  C h o i c e #3: T h i s t r e a t m e n t i s a p i l l completely eliminating angina pain chance of immediate d e a t h .  differently  with  sure.  C h o i c e #2: T h i s t r e a t m e n t i s a p i l l completely eliminating angina pain chance of immediate d e a t h .  This  live  no  C h o i c e #1: T h i s t r e a t m e n t i s a p i l l completely eliminating angina pain chance of immediate death. Take the Take  to  by  representing a  was  explained  a s u b j e c t , the  were e q u i v a l e n t  s u b j e c t be between t h e  prepared two?  indifference  and  four  to  researcher  to the  gamble.  to take  either  This  technique  the  changing  134 Patients shorter risk to  life  who with  of death.  certainty  risk  proportionally. et.al.  aversion  3.1.  averse  than  a  longer  of s u r v i v a l  expectation  (1978) who f o u n d of e a r l y  that death  expected  life  a v e r s i o n was e x p e c t e d  This  to the risk  were  was  to based  cancer  to take a  accompanied decreased  by a  f r o m 75%  i n c r e a s e more  than  on t h e r e s u l t s o f  patients  demonstrated  due t o s u r g e r y .  R e s u l t s and D i s c u s s i o n In  with  risk  As t h e p r o b a b i l i t y  50% t o 25%,  McNeil  were  Table  4.2 t h e  the average  TABLE 4.2.  perceived l i f e  Value  GROUP  results  PER  50%  10.9 5.7  M SD  2.9 2.5  other heart  M SD  4.4 4.5  a n g i na mild  M SD  angina severe  M SD  group  are listed  of t h e group.  Risk  CENT CHANCE OF SURVIVAL  25%  healthy  M=mean;  expectancy  of Avoiding L i f e  (years accepted  Notes:  f o r each  with  certainty) perceived 75% life in years) 18.3 10.7  33.7 13.2  8.3 6.1  14.0 10.7  19.5 11.6  4.1 2.3  7.9 3.4  13.4 6.8  18.7 8.8  2.4 1.9  6.6 3.9  9.4 4.5  13.1 6.0  SD=standard  deviation.  along  135 A comparison presented risk  to  i n Figure  averse  seeking  of the  responses  4.2. T h i s  preferences  preferences  of  figure  of  each d i a g n o s t i c group i s  dedmonstrates  healthy  of patients with  subjects  heart  the r e l a t i v e l y  a n d t h e more  disease.  Figures  4.6 i l l u s t r a t e t h e b i d s made by e a c h d i a g n o s t i c g r o u p .  averse  individual  gamble  for  survival  demonstrated diagonal right the  4.4)  risk  between  rather  levels  patients  than Data  of p a i n  with  would  subjects  (Figure  the forms those  with  by  this  by i n d i c a t i n g their  angina  of previous  by t h i s  question  disability  reduced  disease.  survival. the McNeil  understanding  of  can respond t o  e x p e c t a n c y as t h e anchor  generated  heart  angina  indifferent  of  that patients  standard  coronary  of the  ( F i g u r e 4.6)  and c e r t a i n  a derived  and  on t h e  ( F i g u r e 4.5) were  adaptation  own l i f e  t o any  t h e upper  mild  T h e s e s u b j e c t s were a l m o s t  made  with  with  disease  severe  A risk  4.3) d e m o n s t r a t e d  Patients  of heart  4.3  subject  fall  of the graph with  i s the extension  questions  researcher. high  bids  a  origin.  contribution  preference  If  from  neutral.  preferences  years  a s i s shown by t h e s t e e p n e s s  while  (1978) s t u d y  patient  point,  origin  Y.  t h e gamble o f f e r e d i n t h e q u e s t i o n  The et.al.  his/her  of Y  aversion  and o t h e r  risk  survival  expectation  the  Healthy  risk  averse,  were a l m o s t  with  joining  as i t d e p a r t s  (Figure  certain  neutrality,  corner.  strongest  curve  less  risk  line  hand  prefers a  risk  life  expectancy also risk  s e t by t h e  indicated that avoidance i n  Figure  4.2.  RISK AVERSION IN HEART STUDY GROUPS 120-1  20 H 0  • i  5  1 10  ,  r  15  20  25  Y E A R S OF LIFE ACCEPTED FOR SURE  30  35  F i g u r e 4.3.  UTILITY OF RISK AVERSION IN HEALTHY SUBJECTS 120  - i  Y E A R S OF LIFE ACCEPTED FOR SURE  Figure  4.4.  UTILITY OF RISK AVERSION IN HEART DISEASE CONTROL PATIENTS 120 n  100 H  >  or ZD GO  O >CD < CD  o  cr:  CL  5  ..  10  15  Y E A R S OF LIFE ACCEPTED FOR SURE  Figure  4.5.  UTILITY OF RISK AVERSION FOR PATIENTS WITH MILD ANGINA 120  -i  Y E A R S 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 preferences stood  are  a  was  elicited.  the  question  interviewer  risk.  of  plausible  First,  or  of  years  been  they  reasons  p a t i e n t s may implicitly  t o s t a t e a number o f y e a r s  minimum number the  number  would  S e c o n d , some p a t i e n t s  may  this  set  not  have  under-  encouraged  higher  accept  why  or  lower  of  by  the  than  the  in return for avoiding  have  preferred  the  risky  choice. Since which  p a t i e n t s and  they  agreed  to p a r t i c i p a t e  the  first  alternative  all  groups  equally.  a  s u b j e c t s were  would  The  r a t h e r than  apply  second  by  i n the  order  d i a g n o s t i c group,  a l l p a t i e n t s thus risk  in  biasing  preference,  remains  possibility.  the  heart  figures) in  to  reason,  When e a c h p a t i e n t ' s r e s p o n s e s in  interviewed  any  pill.  e l e c t e d to  other These  prefer death  a 75% over  healthy with  disease  take  the  risk  patients  were  saying,  chance of  complete  angina  wanted  nineteen  the  pill,  p r e f e r r e d the  pill.  i l l n e s s were p r e p a r e d of  symptoms.  in  and heart  pill,  while  the  effect,  with  f o r the  by  two  three  to accept was  in  'pill')  the than  preferred that  a  they  25%  the  would  chance  of  disease.  Among  15  out  patients  of  I t appeared  This behaviour  heart'  (26.3%)  recovery  expectancy  more p a t i e n t s  'other  (identified  of  angina  alleviation  (shown as  Five  a known l i f e  more s e v e r e  group  group.  s u b j e c t s , none a s k e d  mild  severe  control  were e v a l u a t e d ,  of  14  15  patients  with  that patients with  greater  risk  reasonable,  for  the  142 considering  the  effect  of  live  a normal  3.2.  A n a l y s i s of  Utility  The  curves  the  Trapezoidal  method of  this  analysis, "the  score,  the  group to  lower  zero,  negative  score  to  a  the  Table  4.3.  to  determine  order  to  under  results  of  the  score".  The  g r o u p was imply  risk.  risk  would artery  Scores  If as  seeking. to accept the  angina  severe  angina  This Rule  is a  the  the  66. 25  31. 35  have  p a t i e n t or score  risk In t h e  present  whatever pain  was  neutral  and  of D i a g n o s t i c Groups  63. 75  purposes  value  disease.  498. 75  disease controls  the the  SCORE  healthy  real  For  larger  using a  calculations  of  reduce  GROUP  heart  whether  a curve.  identified  prepared  coronary  were a n a l y s e d  the d i a g n o s t i c groups.  the area  Risk Aversion  mild  Aversion  in  treatment  that  with  f o r Risk  the w i l l i n g n e s s  would  treatment  associated  a patient's ability  t o 4.3  n e u t r a l p a t i e n t was a  on  i n F i g u r e s 4.3  aversion was  accept  to  risk  the  risk  Curves  between  determining  termed  close  Rule  existed  for  angina  life.  utility  difference  severe  risk  of  been this  subject zero,  or  while  a  study  a  applied  disability  143 The s c o r e s curve  i n Table  as w e l l as  expectancy The h i g h  perceived of  angina.  Patients  The c l i n i c a l  by  than  subjects  was  with  mild  angina level  receive radiation et.al.  (1978).  score"  i s that  i t allows  treatment  risk  and t h e  patient's l i f e  one s c o r e  willing  The r i s k method  t h a t c o u l d be u s e d  to take  of  considered  a treatment  as  a useful  4.0.  two  treatments no l i f e  This  heart  with  disease  cancer  have been  a t t i t u d e s toward  expectancy  t o be c o m b i n e d  those  p a t i e n t s most  uncertain.  a b o v e i s n o t an Before  should  be  comparison  "risk  orthodox  i t  may  be  compared t o o t h e r was  n o t made i n t h e  study.  Preferences In  f o r lung  utility. i t  greater  measure t o d e t e r m i n e  a patient's  described  measure  more e s t a b l i s h e d t e c h n i q u e s . present  life  of a v e r s i o n .  to identify  expected  a  by p a t i e n t s  and  whose o u t c o m e was  aversion score  describing  utility  The c o n t r i b u t i o n o f a  aversion  into  indicates  i m p l i c a t i o n s of a u t i l i t y  McNeil  of each  the average  demonstrated  an i n t e r m e d i a t e  which p a t i e n t s should described  c o n t r i b u t e d by  healthy  risk  demonstrated  the slope  by t h e members o f e a c h d i a g n o s t i c g r o u p .  the  to treatment  controls  reflect  the weighting  score  aversion severe  as  4.3  f o r Morbidity with  questions  patients  when t h e p r o b a b i l i t y  risks  attached  no  Risk  were a s k e d of success  to the treatment.  to i n d i c a t e p r e f e r r e d v a r i e d but  As was  there  discussed  were  i n the  144 section  on  exerted  by f r a m i n g  the q u e s t i o n groups  'framing' is  in  powerful  previous enough  to a c c u r a t e l y determine  i n w i l l i n g n e s s to  question  the  tolerate  chapter,  the i n f l u e n c e  to impair  the a b i l i t y of  a difference  between p a t i e n t  morbidity  with  no  risk.  The  was a s f o l l o w s :  Would y o u a g r e e t o 2 months o f m a n d a t o r y bed r e s t a t home i f y o u r chances o f c o m p l e t e l y e l i m i n a t i n g a n g i n a p a i n f o r 2 y e a r s were: (answer y e s o r no) yes/no 90% 70% 50% 30% 10% 1% I f you have not a c c e p t e d not a c c e p t bed r e s t ?  4.1.  any of t h e chances  question  did  not s i g n i f i c a n t l y  t h e p a t i e n t and h e a l t h y s u b j e c t g r o u p s . that  angina. with  why w o u l d y o u  R e s u l t s and D i s c u s s i o n This  only  above,  a  groups.  a trend These  appeared  Of t h o s e  of  success  willing  acceptable p r o b a b i l i t i e s  less  willing  to accept  b e l o w 50% t h a n  to take  treatments  of success  between  I t i s p o s s i b l e to report  i n t h e group of p a t i e n t s with  p a t i e n t s were  probability  differentiate  severe  treatments  were o t h e r p a t i e n t  a t home, t h e a v e r a g e  were a s f o l l o w s : h e a l t h y  145 subjects,  53%;  heart  control  angina,  44%, and p a t i e n t s  suggest  that  a  probability  non-invasive  (such  subjects  refused,  four  patients  factors  with  other  rest  included family,  refused,  four  severe by  the  angina  level  treatments  availability  of  mild  These  data  treatments  with  the  treatment i s  t h a n do l e s s  and l i m i t e d  i l l or  explore  age  the  analysed  by  the  of  control  refused, An  indicated  that  he h a d l e f t  and one o f  a  do  These  a job or  'whatever t h e  (the patient  resting  of  contributors  demands o f to  of  number  two m o n t h s .  the r e s u l t s  patient  patients  evaluation  were s i g n i f i c a n t  expectancy  sections  r e s t : one o f 15  refused.  willingness  The  following  angina  a t home f o r  life  life  bed  heart  a caregiver,  of r e s t l e s s n e s s ,  wants',  20  with mild  respondents  to take  level  of  little  d i d not  i n bed).  of the  questions  and t h e p r e v i o u s  health  of the p a t i e n t .  Patient Data  Age a s an I n d e p e n d e n t  from p a t i e n t  d e t e r m i n e whether Patient  i f  to accept  t o w a s t e what  history  even  with  70%.  to take  a t home),  were w i l l i n g  than d i s a b i l i t y  to w i l l i n g n e s s  5.0  bed  patients  angina,  want  success,  o f 15 p a t i e n t s  comments p r o v i d e d  want  of  as  a l l patients  healthy  doctor  severe  51%;  subjects.  Not  14  with  seriously i l l patients  higher  healthy  patients,  age was  not  and  Variable  subject  histories  s e v e r i t y of disease found  to  be  a  was  were  linked  predictor  analysed  to patient of  to  age.  s e v e r i t y of  146 coronary age  or o t h e r  of p a t i e n t s w i t h  while  the  average  59.1  years.  call  that  The  at  age  55.3  was  the  participate When  the  patients h a v e an  with  shown  age  difference  in  it  noted  suggest  be  of  56.7.  that  average  39  that the  as  framing  has  to  the d e s c r i p t i o n  Previous fear,  of  Health  the  a  less  to  average  age  was  artery  bypass  similar  Bias  exerts  than  by  influence, change  powerful  w i l l i n g n e s s to  certain by  framing  found  a  outcome.  age, were  the  23  found  to  demonstrated  t o be  54.7.  significant,  were s m a l l .  of p a t i e n t s w i l l  u n c e r t a i n t y , and  Re-  p a t i e n t s who  groups  as  among g r o u p s .  years, very  statistically  a universal  Experience  was  patient  classified  24  treatment  years,  average  expressed  the  study  56.4  angina  the Framing  framing  not  average  study.  were  was  73  The  severe  coronary  to  Of  age  o n e - t h i r d to one-half  The  with  responses  as  6.0.  that  and  was  where t h e  exhibited a vulnerability  average  of  I n f l u e n c e of  i n a treatment  who  Institute  patient preferences  patient  groups.  similar  study  a range of  to the  has  also  i n the present  c o n s i s t e n t c h o i c e , the  must  a g e s was  reported a  years  over  study  groups w i t h m i l d  Ottawa Heart  study  influence  a  2  Vulnerability This  of  range of  the p a t i e n t groups  5.1.  i n the  v a l v e d i s e a s e or a r r y t h m i a s  age  Chapter  grafting  to  heart disease  and  The but  These  data  t h a t as  many  their  choice  due  outcome.  an  Independent V a r i a b l e  pain associated with  a  myocardial  147 infarction clearly, Since of  even  Zook  health  had  an  feelings that i f the  and care  frequently previous  are  patients  e x p e r i e n c e had  Moore's  that  hospitalized,  the  influence  occurred  (1977) d e s c r i p t i o n o f  suggested  h i s t o r y of  i n the  a heart on  a  patients study  attack  and  patient's  with  sought  study  could  many the  years high  heart to  describe before.  cost  users  disease  determine  were  whether  subsequent h o s p i t a l i z a t i o n attitude  toward  future  hospitalization. The current  research attitudes  question  asked  was:  Would p a s t  towards h o s p i t a l i z a t i o n ?  experience  Patients  were  bias asked  to:  Choose between the following Assume t h a t the treatment has a n o t h e r f o r a t l e a s t two y e a r s . r i s k of h a v i n g a h e a r t attack. H o s p i t a l A: W a i t i n g time f o r 6 months), a f t e r the angina f o r 4 years.  hospitals offering treatment. side e f f e c t s that prevent t r y i n g While you w a i t you b e a r a 5%  is 6 months ( a l l p a t i e n t s h a v e a n g i n a treatment a l l patients are f r e e of  Hospital B: No waiting time, a f t e r the f r e e of a n g i n a f o r 3 y e a r s . A: B:  treatment  patients  are  w a i t 6 months no w a i t  I f you c h o s e h o s p i t a l A, how l o n g would angina pain have to e l i m i n a t e d a t h o s p i t a l B t o g e t you t o c h o o s e h o s p i t a l B?  be  I f you chose h o s p i t a l B, how e l i m i n a t e d at h o s p i t a l A to get  be  l o n g would a n g i n a p a i n have to you t o c h o o s e h o s p i t a l A?  148 6.1.  Results Of  and D i s c u s s i o n  t h e 64 s u b j e c t s  infarction choices  and 43 had  of these  TABLE 4.4.  interviewed, not.  21 had s u f f e r e d a  Table  4.6  Myocardial  Infarction  and W a i t i n g  no w a i t  10  (47 .6%)  11  (52 .4%)  21  no h e a r t attack  16  (37 .2%)  27  (62 .8%)  43  total  26  38  64  p=0.42  Table  4.4  shows t h a t  h a v e had a h e a r t treatment  than  (48%  versus  This  question  attack those,  a greater are  including  37%) , a l t h o u g h  this  of w i l l i n g n e s s  for  survive a  diagnostic  a heart  attack.  more s e n s i t i v e  willing waiting.  to  wait  from  to wait  could  six  subjects, not  of the and  who  have not  significant.  possibility  surgery  signifiof long  for patients may  who  months f o r  has c o n s i d e r a b l e  administrators  approach  of p a t i e n t s  wait  d i f f e r e n c e was  Health  those  to  healthy  procedures  some ex a n t e d e t e r m i n a t i o n  proportion  willing  i n the h o s p i t a l - system because  waits  offer  Choices  total  heart attack  cance  the waiting  subjects.  wait  Notes:  summarizes  myocardial  be  who  able to  to p a t i e n t s r e q u i r e d to wait i f be  whose  used  to  anxiety  differentiate was  those  i n c r e a s e d by  149 7.0.  The The  I n f l u e n c e of waiting  to determine altered  wait  26  for  these dent  q u e s t i o n s were  i f previous  willingness  overall,  a Coronary  Choices  also  by  bypass  to wait  analysed with  hospital  care.  Table  s u b j e c t s when b y p a s s  surgical  f o r treatment.  s u b j e c t s p r e f e r r e d to wait 4.5  while  summarizes  experience  is  intervention  In the 38  study  d i d not the  history  group  want  to  preferences  of  considered  an  indepen-  variable.  bypass  7  no  19  bypass  total  no  (58.3%) (36.5%)  Fisher's  The  months  to wait  who  When t h e s e  (41.7%)  33  12  (63.5%)  52  64  p=.14  of a n o t i c e a b l e , but  the p r o p o r t i o n for hospital d i d not  surgical  total  38  appearance  ence between  wait  5  26  Notes:  with  on  experience  wait  six  A r t e r y Bypass  of  bypass  c a r e , compared  have a bypass,  treatment  increased  p a t i e n t s were a s k e d  not  significant  differ-  patients willing  to  to  willing  the  suggested the  proportion that  an  wait  experience  tolerance for waiting.  t o d e s c r i b e why  t h e y were  willing  150 were w i l l i n g nearly heart "I  to wait,  s i x months f o r attack  found  always  having  want a n o t h e r One  too  is  hospital  risk  p r e s e n t ; s i x months  isn't  a  that  really  could  people  have been  considerations, identified  availability  with  were:  a  unpleasant  by  be  with  c a r e a r e more a n x i o u s  problems to  bypass  replies  "I  of  had  to  having  a bad  wait  another  wait."  and,  experience, I  don't  soon."  that  t h a n p e o p l e who policy  my  a bypass  conclusion  findings  t h e common  in  little  system  constraints  may  be  to  before. that  exaggerated  identified  by  available  In  the  these  intensive  immediately  could suggest  non-users  drawn f r o m  exposure  to have c a r e the  one  tentatively  terms  of  availability when  t h o s e who  compared have  used  hospitals.  8.0.  H e a l t h E x p e r i e n c e and How  does a  infarction  that  to  of  accept in  Chapter  option of  risk  pain  6 years  carries death  in  a risk  of death?  The  3 i n the d i s c u s s i o n  d e s c r i b e d i n T a b l e 4.6 w i t h no  of p a i n r e l i e f  risk  with  influence  the past  i n the f u t u r e .  relief  Avoidance  experience  or a c o r o n a r y bypass  treatment risk  personal  Risk  either  a patient's I t appears  the  of death. by  has  certainty  i s a treatment  accompanied  myocardial c h o i c e of  that  i n c r e a s e s a person's  q u e s t i o n used of  a  The a 10%  ability  The  offered  second risk  exposure to  been d e s c r i b e d  effect.  that  a  option  of d e a t h .  5  first years  offered The  151 expected longer  value  than  of  the  the f i r s t  second  treatment  o p t i o n was  0.4  years  option.  8.1. R e s u l t s and D i s c u s s i o n Table cations  4.6  summarizes  the  o f s u b j e c t s by p r e v i o u s  TABLE 4.6.  Health  Experience  past history  findings health  and R i s k  across  five  experience.  Avoidance  choice take  5 f o r sure  take  6 with  risk  total  no MI & no b y p a s s  39  (92.9%)  3  (7.1%)  42  h a v e had MI  16  (76.2%)  5  (23.8%)  21  h a v e had bypass  10  (76.9%)  3  (23.1%)  13  b o t h MI & bypass  6  (66.6%)  3  (33.3%)  9  all subjects  58  (90.6%)  8  (9.4%)  notes:  classifi-  (a) MI = m y o c a r d i a l (b)  In t h e Mantel  What became a significant patients  apparent  trend  infarction  test from  f o r trend d i f f e r e n c e s , the r e s u l t s  i n the r e s u l t s  were e x p o s e d  64  to the s t r e s s  of  p=.027  of the Mantel  Table  4.6,  of myocardial  was  test for t h a t as  infarction  and  152 bypass  surgery,  proportion 10%  risk  of death with  i s three  (7%) .  value  i s higher  by  a 10%  option  certainty,  analysis  experience  with  a predictor of  death  risk  of death  the  classified this  vast  the  10%.  higher  expected was  not  t o note  expected  patients with is  but  compare  increase  to is  years.  acting  angina  who  only  a  as  risk were  included i n In T a b l e  of angina  bear  year  a patient's  current angina.  willingness  significant.  no p a i n  carried  p a t i e n t s were  the  of subjects  variable  s u m m a r i z e d by l e v e l  the  than f o r  with  v a l u e o f 5.4  to  a  past  that although  (90.6%)  previous  control  with  i t i s f o r the f i v e  majority  with  increases  gain,  (23%)  c h o i c e when a t r e a t m e n t  disease  choice  that angina  or bypass  than  conducted  Patients  along with  risky  treatment  The  f o r patients with  p a i n as an i n d e p e n d e n t  heart  showing  difference  also  angina  as  analysis,  4.7,  was  increased.  f o r the o p t i o n of s i x years  of treatment of  larger  infarction  were n o t i n f l u e n c e d by t h e h i g h e r An  risk  f o r the  I t i s of i n t e r e s t  accompanied with  to opt times  a myocardial  without  expected  w i l l i n g n e s s t o assume  of p a t i e n t s w i l l i n g  experience those  their  risk 10%.  pain, for a This  153 TABLE 4.7.  Angina 6  years  P a i n and with  Risky 5  risk  Choice  years  for  total  sure  angina  4  (21.1%)  15  (78.9%)  19  no  4  (11.4%)  31  (88.6%)  35  angina  Notes:  9.0.  T h e r e was  Health Study  words the  subjects  " s u r g e r y " or  offered  no  by  "drug  matched  these  two  question  treated  surgically  probabilities  coronary  artery  (n=20), t h e question. had  one Among  of  treatments,  optimal  treatment.  severe  angina  Of  (n=14)  outcomes  described  in  Chapter  patients  who  the  least In who  two while some  All  one  heart  selected  three selected  had  already  of  heart  received a group i n the  (n=15), f i v e p a t i e n t s  surgery  interest,  had  been  outcome  chose s u r g e r y  angina  The  already  disease control  a bypass mild  1.  groups  who  the  outcomes  whose  three  patient  the  had  had  treatment  use  described in  treatment  surgery?  who  the  Treatment  of  would  p a t i e n t s with only  but  groups.  t h a t d i d not  probabilities  bypass.  a bypass but  choice  the  between  Surgical  a question  prefer  patient  of  therapy",  asked:  at  difference  Choice  methods as  matched  contained  and  were g i v e n  research  patients  significant  Experience  question  54  46  8  total  a l l had  as drug six  their  optimal  therapy  as  the  p a t i e n t s with  a bypass  selected  154 surgery  again  It  is  of  preferences  may  their  important  discussion  treatment  as  here  preference for  based  place  p r e f e r r e d treatment  the  the  or  ability  p a t i e n t s who  the q u e s t i o n  asked  of  of  the  for  3 and  the  above d i s c u s s i o n of  treatment,  p a t i e n t s chose a  outcomes.  The  shown t o be  bid  to Chapter  participants  were n o t  for a  back In  drug  probability  d e m o n s t r a t e c o n s i s t e n c y was number o f  reflect  reversal.  surgical on  on  to  outcome.  in  misplaced  reliance  a d e c i s i o n to because  consistent in their an  outcome  one  of  the  c h o i c e when  versus  a  direct  choice. If  some p o l i c y  interpretation might  focus  patient  who  of  suggestions  patient preferences  on  making  demonstrated  surgery a  outcomes.  In  patients  with  mild  angina  for  drug  therapy.  Recall  the  preferences encourage An  discussion of  analysis  question  asked  influence  on  who  in  r a t h e r than  was of  also  study  whether  available  present  p h y s i c i a n s and  treatment  classification  the  treament,  they  severely  ill  consistent preference  for  sixty  a  bypass  T h i s may  be  an  Chapter  1  the  the t e n t a t i v e  f o r the  study,  had  per  cent  of  demonstrated  over-treated  that  economic  group.  identified  incentives that  a  the could  non-treatment.  conducted groups symptoms  patient choices.  drawn f r o m  for surgical  s t r o n g and  surgical  preference  c o u l d be  by  on  treatment  diagnosis.  such  as  pain  choices The acted  using  research as  an  155 TABLE 4.8.  Diagnosis surgical  as a n I n d e p e n d e n t V a r i a b l e  choice  drug  choice  total  healthy subjects  8 (55.3%)  other heart  10  mi I d angina  8 (55.3%)  7 (46.7%)  15  severe angina  12  2 (14.3%)  14  Notes:  (50%)  (85.7%)  7*  (46.7%)  15  10  (50%)  20  (a) One p a t i e n t i n t h e * g r o u p 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 b e t w e e n g r o u p s was n o t 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 severe  angina  chose s u r g e r y significant  on t r e a t m e n t over  drug  difference  i n the  for  disease  or p a t i e n t s with  of  this  disability to  treat  10.0.  a s 85%  T h e r e was a l s o  rate  of  suggest  o f symptoms and  mild angina.  should  that  except  for  therefore  implications  preferences with  be e l i c i t e d  medical  forms o f h e a r t  The c l i n i c a l  those  group  statistically versus  other  patient  i n f l u e n c e of of this  no  surgical  healthy subjects, patients with  finding  independent  c h o i c e appeared  therapy.  choices  significant  severe  before  may  be  pain or  the d e c i s i o n  i s made.  Summary This  predictor services  chapter of  h a s shown t h a t  interest  in  associated with  patient  age  or w i l l i n g n e s s  coronary  artery  is  not  a strong  t o consume h e a l t h  disease.  P a i n has  care  156 appeared  as  a  variable  capable  willingness  t o seek  be  to the p a t i e n t .  of value  lengthened the  had  No p a t i e n t s treatment.  h o s p i t a l system acted  to increase  as t h e a v e r s i o n a  bypass  surgery  to surgery  (CABG).  Patients  a p p e a r e d more a n x i o u s  The  r e s u l t s reported  disability  may  preferences  f o r treatment  11.0.  be  Limitations The  limited  2,  response  in  the  gists  and o n l y  partial  who  the tolerance  Patients  who  had  as  already major  treated. suggest  that  pain  determining  heart  and  patient  disease.  of t h i s  study  has b e e n  including selection bias,  replication  of other  patients  small  studies.  In  identified  the  receiving  treatment  of the Vancouver General  Hospital.  response  et.al.,  willing  patients rates  by  as h i g h  hospital cardioloas t h o s e  i n other  1982). to  t o be more l i t e r a t e  interested  with  of waiting  had no e x p e r i e n c e w i t h  chapter  ambulatory  Division  not produce  (Torrance  a cure or a  experience  of s e l e c t i o n of subjects  among  Cardiology  did  appeared  Previous  of coronary  r e c r u i t i n g of preselected  studies  tive,  rate  deemed t o  variables  of f a c t o r s  a discussion  low  f o r treatment  of the Study  a number  sample s i z e ,  Direct  important  increased  among p a t i e n t s  t o be  in this  an  were o f f e r e d  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 by  Chapter  influencing  and t o w a i t  by t a k i n g  well  life  treatment  of  i n medical  participate than  in  the  questionnaire  the average p a t i e n t /  d e c i s i o n making, had s t a b l e  introspecangina or  157 other  heart  once.  This  number  disease, group of  of  errors  biased  by  tion,  it  recent  myocardial  ment  less  of  appears  who  a  be  that  more reduce  the  patients  for a  structured,  was  from a s p o r t s The  medical and  Almost  factors  need  method  was  the  a  was  func-  angina,  even  a  treat-  more  so.  will  also  more  pain; a l l  than of  have  decision ambulatory  expressing  'heavier have  development recreational  lifestyle  healthy  although  or  than  been and  had  due  to  s e l e c t i o n of  c l u b whose members were p r o b a b l y risk  some s t a t e d with  shown  should to  ' s e v e r i t y of  a t h l e t e s was  No  a  that  their  play  a  coronary  considered  jobs  severe  significant  t o be  a  in  the  between  the  smoked  or  were s t r e s s heart  disease  many a d m i t t e d  Since  heart  healthier  subject  s m o k e r s and be'.  healthy  identified  healthy  moderate or  been heavy they  factors  noticeably different  subjects.  a l l patients  were c u r r e n t l y being  of  rational  sequential  h i s t o r y were  the  overweight,  ful.  or  of  have a g r e a t e r  level  a prompt  probably  likelihood  sample b i a s  average.  patients  vulnerable,  to  sample  unstable  t o make  and  than  preference.  A related  subject's  as  study  average'  a need  anxiety,  p a t i e n t s may  than  the  h a v e been h o s p i t a l i z e d f o r t r e a t m e n t  These  subjects  Although than  more  vulnerability  p a t i e n t s with  or  just  cardiologist  demonstrated  that  making.  treatment  their  'better  likely  will  seen  judgement.  infarction,  confidence,  variables  had  patients  patients with  choice  Patients  and  lifestyle role  disease,  the  justifiable  to risk  in  the  use  of  choice.  158 A second to  replicate  studies  in  et.al.,  1982;  previous  for  Slovic,  1971)  choices,  and  presence  of  and  errors  money.  to  terms  preference  reversal was  influence  a  making  in cases  nature state  of  prepared the  where  per to  used,  cent  of  were  the  o n l y as  had a 5%  For  been  a strategy  not  the  to  demonstrated  by  'new  currency',  judgement the  such  as  purpose  of  that  a true units  to  the  p r o v i d e d an decision  measure.  hypothetical  subjects  were  asked  to  income'  they would  be  p o s i t i o n on a w a i t i n g  heart  could  preference.  appropriate  due  example,  assigned. of  the  u n d e r s t a n d i n g of  'retirement  a better  risk  of  s t u d y was  their  exchange f o r  carried  not  dollars  questions.  p o s i t i o n they  waiting  scope  general  treatment  test  judgement  express  and  for  However, of  w i t h more  the  l i m i t a t i o n of  to  of  the  questions  for  to  using a  errors  as  Lichtenstein  created  of  errors  ability  increase  the  the  identify  no  McNeil  d e v e l o p e d by  appropriate  misplaced.  s u c h an e r r o r  to  A third  to  patient's  Demonstrating opportunity  identifying  but  previously  As a r e s u l t  may be  served  1984;  was  important  1981)  questions  1979,  judgement  and  attempt  1978;  questions,  not  d i d not  et.al.,  and M c N e i l ,  were  it  acclaimed  (McNeil  'currency'  of  that  addition,  Tversky,  a different  involving  study  In  u s i n g money b e t s  reference  the  making  preference  replicated.  (Kahneman  Several  Pauker,  a number o f  others  s t u d y was  studies.  and P a u k e r ,  actually  choices  the  medical decision  foundation were  l i m i t a t i o n of  Subjects  attack.  probe w a i t i n g ,  were This  but  list  than  told  that  question as  a  was  strategy  159 to  try  to  patients  understand  f o r whom t r e a t m e n t  measured  by  Patients  demonstrated  completely this  risk  these bear be  response  their  had a low o r  willingness  deterred  very  to  some p a t i e n t s  questions risk,  to  negative  responses:  from w a i t i n g , As a r e s u l t  nature  identified value  'pay' t o be t r e a t e d  differentiate  the h y p o t h e t i c a l  The s t u d y  even  different  t o be i n c o n s e q u e n t i a l .  patients of  the  while  sooner. 5%  risk  others  of the  as  felt  a b i l i t y of  who were w i l l i n g t o  the questions  was f e l t  to  justified. Finally,  participant  the in  role  medical  limitation  the  d e c i s i o n makers.  usual  physicians  do  of  i n the  patients  developed  neither  nor  nature  of the  Division of  of Cardiology  British  constrained than  present  Columbia. about  they d i d with  not  informed  had  previously not  patient's  making  a  Patients  role  this  that  'making a  used  to  regarding confirm  preferences  treatment. any  f o r future  of a  treatment.  threatening  supported  many  to  was  treatments.  the but  less  person  deliberately  the physician  decisions,  felt  a para-medical  Thus  by t h e  of the U n i v e r s i t y  patients  The r e s e a r c h e r  i n advance o f any d e c i s i o n s made  1 h a s shown, some  was  was  mistake' with  a physician.  a  and p h y s i c i a n s a r e  Committee  addition,  as  Due t o t h e p r e l i m i n a r y  role  and t h e E t h i c s In  perceived  i n the choice  the physician.  study  as a non-medical  was  However, a s C h a p t e r  not involve  patient  researcher  study.  Thus, t h e r e s e a r c h e r the  the  decision  potential  was  to risk.  or p a t i e n t  questionnaire  to explore  the  160 11.0.  Conclusions Several  study.  trends  First,  subjects  making  disease.  These  choice  and by  selected  a second  pattern  of  disease. accrue  heart  disease  the  there  factor  results  who  as  judgement  i f  they  (the  by  is  a chance axiom  of  the have  healthy  had  heart  wording  reversal  a competing  of  the  (whether  the  asymmetric  to g a i n  or  to  (when a  choice  was  choice  i t was  not  life)  risks  For  risk a heart  heart  with  serious  in a realistic  previously  and  merit  may  environment time  consumpatients  a  treatment  example, p a t i e n t s w i t h  diagnosed  to  choice  than  attack. a  the  The  faced  heart  by  averse  disease,  different  considerable  more d i f f i c u l t  relationship  were more by  that  making  be  exhibited a  subjects  suggest  decision  a positive  accompanied  were h e a l t h y  than  s t u d i e s may  (and  bypass.  of  and  framing  preference  results  disease  'as  substitution  aversion  were p a t i e n t s w i t h coronary  heart  choice  when  u n c e r t a i n outcome.  disease  errors  the  for influenced preference),  study  studying  demonstrated  by  time).  These  Health  an  of  same  i n the  though such  ing.  choice), or b i d  risk  to  with  included  differ  the  Subjects  patients treatment  violation  identifed  identified  errors  chosen  changed  with  a  (choices  lose),  even  by  influenced  outcome was  been  previously  been demonstrated  question  have  of  patients greatest  previous  heart  with risk  heart  seekers  attack  and  a  161 Several  expected  subjects  did  younger  subjects.  women, no  not  did less  coronary  bypass  preferred  errors  a of  13.0.  in  the  create be  the  of  the  who  than  subjects  future  patients on  preferences  identified.  influence  i t (based  has  for  were  Previous  choices. had  For  received  a  o u t c o m e p r o b a b i l i t i e s ) as  a  demonstrated  treatment.  and  assist  that  As  professionals  with patients  physicians present of  such  who study  the  patients  for Further  patients  more  can  patients  i s known  can about  i m p r o v e methods  of  to p a r t i c i p a t e i n  express  a tool,  permitted have  refinement  Ambulatory  need  participate in  patients  in this  their  as  patients  expressed  an  to p a r t i c i p a t e  interest  into a t o o l capable  a preference  involving patients  the'physician  Research  questionnaire  angina.  of  be  Older  decisions.  required  to  treatment  could  to  judgement, h e a l t h  development helping  demonstrated.  one-fifth  sex  of  study  preference  Opportunities The  to  not  treatment.  the  communicating treatment  half  selected  future  only  appear  than  Finally,  due  were  different  Since  not  example,  express  exhibit  differences  treatment  trends  of  for  treatment.  questions with  well  and  in  of  actually  In  order  techniques  unstable  as  as  in hospital  those  well  testing e x i s t i n g questions. d e c i s i o n would  add  to  the  the  as  to  would stable would  Involvement understanding  162 of  such  a  decision  tool  a  participation in  medical  making.  Further would  in furthering patient  also  testing  be  higher  of  of  the  value.  response  In  rate  questionnaire  addition, among  one  the  with  would  larger  hope t o  patients  in  groups  encourage  a  cardiology  practice. The pose  role  a  of  threat  Evaluating  the  para-medical patients  of  ability  errors  field  about  health  to  of  a  of  is  a  the  underway  in  of  errors  interest.  of  The  towards  to  judgement avoid  expression the  of  would  situations a  patient's  t h e o r e t i c a l development  psychology  significant.  every  of  other  person.  professionals  most o f  is  be  to  physicians.  positive feelings  understanding  endanger  medicine  also  indicated  health  the  nurse p r a c t i t i o n e r or  would  'neutral'  nor  developed  provincial  and  One  has  budget  economics, i t s only is  to  recall  devoted  to  care.  influence  of  analysis  t h e o r y may setting  to  t h i s s t u d y was  patients  Although  one-third  Finally,  and  study  could  preferences.  application  role  work t o w a r d  the  this  that  present  in  the  professional  preferences  where s u c h true  neither  health  Further increase  to  researcher  potential  i n the  expressing  the  be  out  it  is  research of  important bias  data.  more l i k e l y to  i n the  find  A to  to  acknowledge  d e l i v e r y of  researcher find  such  contradictions  the  the  s e t t i n g out evidence to  potential  questionnaire to  than a  established  support  a  researcher theory.  163 Efforts bias,  must be  and  i n the  objective for  case  Final As  broad  from  understand been based  produce not  general  evidence  paradigms,  of each  without  to s t r i v e  paradigm  to o f f e r  to  be  a model  behaviour.  decision  a s m a l l sample s i z e of data  patient on  preferences  conclusion  these questions useful  with  each  did,  may  larger  those samples.  for this  subject.  with  Efforts  a to  c o n d i t i o n s have  making as w e l l  as  on  of o c c a s i o n s ,  drawn  specific. as  research  the  a  results.  be  this  differentiate  previous reports  that  as w e l l  on  to  significant  are s i t u a t i o n  compensates  i n medical decision  groups  support  making,  under d i f f i c u l t  Attempts  of p a t i e n t  always  but  collected  p r e v i o u s work  statistically  preferences  be  competing  of m e d i c a l  disciplines.  preferences  would  human  study  spectrum  other  of  interpret  Comments  a case  suffers  r e s e a r c h e r s to  r e g a r d i n g the a b i l i t y  understanding  14.0  did  made by  number Although i n the from  the  findings  literature,  the study  However, with  treatment  i s that  replication  non-significant  a  of  findings  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 R e s e a r c h S e r v i c e s  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:  MacCrimmon, K.R.  UBC DEPT:  COMM & BUSINESS ADMIN  TITLE:  P a t i e n t p a r t i c i p a t i o n i n the d e c i s i o n of c o r o n a r y bypass s u r g e r y  NUMBER:  B85-081  CO-INVEST:  Vertinsky, I.  APPROVED:  F u l t o n , M.J.  MAY 2 7 1985  The p r o t o c o l d e s c r i b i n g t h e above-named p r o j e c t has been reviewed by the Committee and the e x p e r i m e n t a l p r o c e d u r e s were found t o be a c c e p t a b l e on e t h i c a l grounds f o r r e s e a r c h i n v o l v i n g human s u b j e c t s .  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 O F MEDICINE, Heather Street, ouver, B . C . V5Z 3J5  June 6, 1985  M a r i a n Jane F u l t o n Doctoral Candidate i n t o D i s c i p l i n a r y Studies F a c u l t y o f M e d i c i n e and F a c u l t y o f Commerce and B u s i n e s s A d m i n i s t r a t i o n The U n i v e r s i t y o f B r i t i s h Columbia Vancouver, B.C.  Dear Ms F u l t o n : Dr. K e r r has s u b m i t t e d t o me d o c u m e n t a t i o n r e l a t i n g t o y o u r p r o j e c t e n t i t l e d " P a t i e n t P a r t i c i p a t i o n i n the D e c i s i o n of Coronary Bypass S u r g e r y " . I h e r e b y g r a n t you f u l l a u t h o r i z a t i o n t o c a r r y o u t t h i s p r o j e c t among o u t p a t i e n t s s e e i n g members of t h e D i v i s i o n o f C a r d i o l o g y on t h e 3 r d F l o o r o f t h e D o c t o r s ' R e s i d e n c e . This approval w i l l be s u b j e c t t o o b t a i n i n g w r i t t e n a p p r o v a l from the UBC E t h i c s Committee, as w e l l as from t h e Vancouver G e n e r a l H o s p i t a l R e s e a r c h Committee. I have i n d i c a t e d t o Dr. K e r r 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 w i t h o u t f u r t h e r d e l a y i n g t h e s t a r t - u p o f your p r o j e c t . I t w i l l be o u r p l e a s u r e t o c o - o p e r a t e w i t h 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 l o o k f o r w a r d t o s e e i n g the r e s u l t s . Yours s i n c e r e l y ,  c . c . Dr. C. R. K e r r  166 INTRODUCTION TO THIS QUESTIONNAIRE A note  to p a r t i c i p a n t s :  The purpose of this research p r o j e c t i s to gather that w i l l help doctors to understand how p a t i e n t ' s can i n f l u e n c e t h e k i n d o f t r e a t m e n t chosen.  information preferences  This choice c a n be very important to heart p a t i e n t s because d i f f e r e n t t r e a t m e n t s have v e r y d i f f e r e n t e f f e c t s . We a r e a s k i n g y o u t o a n s w e r t h e q u e s t i o n s we h a v e given you. A researcher w i l l h e l p you w i t h t h e q u e s t i o n s i f y o u w i s h . I f you do n o t w i s h t o c o m p l e t e the questionnaire, or there a r e some q u e s t i o n s y o u do n o t want t o a n s w e r , t h a t ' s a l l r i g h t . Since the answers are completely anonymous, no one w i l l know. This confidentiality also allows you t o be c o m p l e t e l y c a n d i d a b o u t your p r e f e r e n c e s . Some q u e s t i o n s ask you t o answer y e s o r no, some a s k y o u f o r "how much" of something, and some a s k y o u t o c h o o s e b e t w e e n two gambles. These questions relate to heart disease generally, they do not a p p l y t o you d i r e c t l y . There a r e no ' r i g h t * a n s w e r s . We assume t h a t i f y o u a n s w e r t h e q u e s t i o n s your consent. We w i l l keep your answers you n o t t o w r i t e y o u r name on t h e p a p e r .  t h a t y o u have g i v e n us c o n f i d e n t i a l by a s k i n g  When y o u h a v e f i n i s h e d t h e q u e s t i o n s , t h e r e s e a r c h e r w i l l t a l k t o you a b o u t them. I t i s n o t uncommon f o r a few p e o p l e t o f e e l some a n x i e t y a b o u t t h e i r own i l l n e s s a f t e r they think about b e i n g i n h o s p i t a l o r b e i n g an i n v a l i d f o r some t i m e . The r e s e a r c h e r w i l l answer y o u r q u e s t i o n s a b o u t t h i s a l s o .  16 7  CONSENT FORM  I,  , authorize (name of  Dr. that  patient) to inform Jane F u l t o n ,  I have heart d i s e a s e .  I understand  M.Sc. that my  i n the U n i v e r s i t y of B r i t i s h Columbia r e s e a r c h "Patient P a r t i c i p a t i o n  i n the D e c i s i o n to T r e a t  Heart D i s e a s e " i s v o l u n t a r y . ( s i g n a t u r e of  patient)  participation  project Coronary  16 8 page 1  PARTICIPATING IN DECISIONS  INSTRUCTIONS: Please v i s u a l aids a v a i l a b l e . any q u e s t i o n s .  answer the f o l l o w i n g q u e s t i o n s u s i n g the The r e s e a r c h e r i s here to h e l p you w i t h  HISTORY: age  sex  date  Doctor's  name  Doctor's  diagnosis  Angina p r e s e n t  not present  D e s c r i p t i o n of symptoms: -duration -onset  after exercise  - d u r a t i o n of r e l i e f Working s t a t u s : health status: -other c h r o n i c i l l n e s s -other h o s p i t a l  stays  -other f a m i l y i l l n e s s  Family s t a t u s : -mar i t a l -children Lifestyle  risk  factors:  -smoking h i s t o r y  -weight -stress  number of years smoked do you s t i l l smoke when d i d you q u i t  169  page 2  THE  QUESTIONNAIRE  NOTES: 1. In some q u e s t i o n s you by a number such as 30%. of 100 p e o p l e .  w i l l see the word 'chance' accompanied T h i s can be thought of as 30 people out  2. Some q u e s t i o n s s t a t e that angina p a i n may be years. These 2 years are p a r t of the t o t a l number you expect to l i v e .  reduced f o r 2 of years that  3. When you are asked to make a c h o i c e , t r y to t h i n k of i t as being a f i n a l c h o i c e . I f 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 ?  2. P l e a s e identify h o s p i t a l care are to statement. a) There very  how you.  i s no w a i t i n g l i s t  important\  b) Treatment  \  the following aspects of 'X' on the l i n e below each  f o r treatment. \  \  \  \not  important  i n h o s p i t a l takes l o n g e r than 2 weeks.  very important\ c) Angina  important Mark an  years  \  \  pain i s controlled  very important\  \  \  \ by  \  \not  important  \not  important  treatment. \  \  3. 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 pain for 2 years were: (answer yes or no) Chance of r e d u c i n g angina p a i n f o r 2 y e a r s : yes/no 90% 70% 50% 30% 10% 1%  170 page  3  4. After 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 h a v e p a i n t w i c e as o f t e n as b e f o r e t h e t r e a t ment.The numbers below a r e chances that the treatment will e l i m i n a t e angina pain f o r 2 years. Which of t h e s e groups would be a c c e p t a b l e t o you? c h a n c e o f no p a i n A. B. C. D. E.  pain  90% 70% 50% 30% 10%  twice  as o f t e n  yes/no  10% 30% 50% 70% 90%  If A i s n o t a good enough ' c h a n c e ' f o r i m p r o v e m e n t , what w o u l d 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 l o w e r c h a n c e i s n o t a c c e p t a b l e ?  chance  5. I n e a c h o f t h e s e q u e s t i o n s you h a v e t o s p e n d 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 a r e in the h o s p i t a l . To  completely  e l i m i n a t e angina  for  1 year,  for  5 years,  I would  for  the r e s t  o f my  What w o u l d hospital?  I would  you be  pain:  spend  weeks  spend  life, giving  weeks  I would up  spend  i n order  weeks t o spend  6. S t a t e how many weeks you w o u l d be p r e p a r e d to a c h i e v e t h e f o l l o w i n g outcomes: Outcome A: 98% c h a n c e o f no a n g i n a 2% c h a n c e o f p a i n A  pain  t h e same  these  to stay  weeks i n  in hospital  f o r 2 years as i t i s now  for 2  years  weeks  Outcome B: 25% c h a n c e o f no a n g i n a p a i n f o r 8 y e a r s 75% c h a n c e o f p a i n t h e same as i t i s now f o r 8 y e a r s B weeks  171 page 4 7. L i s t e d b e l o w a r e some h y p o t h e t i c a l p r o c e d u r e s w i t h r i s k s and b e n e f i t s l i s t e d , w h i c h one would you choose? Assume t h a t you cannot have b o t h t r e a t m e n t s . treatment group A: T h i s treatment completely e l i m i n a t e d angina p a i n f o r 2 y e a r s f o r 80% o f p a t i e n t s ; 15% s t i l l had p a i n , and 5% died i n h o s p i t a l . treatment group B; T h i s treatment completely e l i m i n a t e d angina p a i n f o r 2 y e a r s f o r 60% o f p a t i e n t s , 40% had t h e same p a i n they had before the treatment, no patients died because of the treatment. no treatment treatment  A  A B  angina  80% 60%  or B  y o u c h o s e A, what % o f g r o u p g e t you t o j o i n t h e group?  If to  y o u c h o s e B, what w o u l d j o i n the group?  8. T h e s e t r e a t m e n t you p r e f e r ?  groups  no  angina  A What  A B or B  risk  15% 40%  5% 0%  of d e a t h  o r no p r e f e r e n c e  If to  treatment treatment  same p a i n  70% 55%  B  would %  t h e outcome  have t o have p a i n  relief  i n A h a v e t o be t o g e t y o u  have d i f f e r e n t  outcomes, which  same p a i n  risk  15% 35%  15% 10%  o r no p r e f e r e n c e  o u t c o m e s d i d you f o c u s on i n m a k i n g  your  choice?  group  of death  do  172 page 5 9. L i s t e d ' 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 risks. Choose one. Assume t h a t i f you s u r v i v e the treatment you w i l l l i v e as long as you e x p e c t , but you w i l l have angina p a i n . treatment group A: T h i s treatment completely e l i m i n a t e d angina pain f. 6 years f o r 90% of p a t i e n t s ; 10% of the p a t i e n t s s u f f e r e d c o m p l i c a t i o n s of treatment and d i e d . o r  treatment group B: T h i s treatment p a i n f o r 5 years f o r a l l p a t i e n t s . A  or B  completely  e l i m i n a t e d angina  or no p r e f e r e n c e  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? \ I f you chose B, how many more months would A need to choose A? 1 month 2 months 3 months 4 months 5 months 6 months , more than 6 months?  get you to  10. How l o n g can you e x e r c i s e b e f o r e angina pain? How many b l o c k s can you walk without angina? 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 pain after 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: pain.  twice as much  A: 50/50 chance B: twice as much f o r sure  exercise  for  sure  with  no angina  173 page 6 11.  Choose between  treatment exercise,  the f o l l o w i n g  treatments:  A: 50% chance of no a n g i n a pain after 50% c h a n c e o f n o t b e i n g a b l e t o e x e r c i s e  t r e a t m e n t B: a c e r t a i n l o s s o f b e f o r e a n g i n a p a i n t h e same as A: B:  two  1/2 your i t i s now.  any amount at a l l ;  current  exercise  of  time  50/50 c h a n c e 1/2 l o s s f o r s u r e  12. F o r t h i s q u e s t i o n use t h e number o f y e a r s you e x p e c t t o l i v e as t h e y e a r s f r e e o f a n g i n a p a i n . S t a t e how many y e a r s o f l i f e you w o u l d t a k e ( w i t h a n g i n a l i k e you have now) in order to be i n d i f f e r e n t between the y e a r s w i t h a n g i n a and t h e f o l l o w i n g g a m b l e s . Would you agree to take complete r e c o v e r y from your death? yes no Would heart  a  pill heart  that offered disease and  a 98% c h a n c e a 2% risk  you a g r e e t o e x c h a n g e a l l t h e y e a r s you e x p e c t d i s e a s e f o r one y e a r o f p e r f e c t h e a l t h ? yes no  to l i v e  of of  with  C h o i c e #1: T h i s t r e a t m e n t 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 completely eliminating angina pain f o r your l i f e t i m e and a 50% c h a n c e o f i m m e d i a t e d e a t h . Take  years  of  life  f o r sure  instead  C h o i c e #2: T h i s p i l l has a 75% chance of y o u r l i f e t i m e and a 25% c h a n c e o f d e a t h . Take  y e a r s of  C h o i c e #3: This p i l l y o u r l i f e t i m e and a 75% Take  years  of  life  f o r sure  has a 25% chance of  life  f o r sure  instead  the  complete  instead  chance of death.  of  of  the  complete  of  the  pill.  recovery for pill.  recovery f o r  pill.  174 page  7  13. Please c h o o s e between t h e f o l l o w i n g o u t c o m e s o f a t r e a t m e n t for your a n g i n a . When you f i n i s h t h e t r e a t m e n t assume t h a t you must l i v e y o u r e x p e c t e d l i f e w i t h a n g i n a . Treatment  A:  98% 2%  c h a n c e o f 2 y e a r s w i t h no a n g i n a p a i n , c h a n c e o f p a i n t h e same as i t i s now.  and a  Treatment  B:  25% 75%  c h a n c e o f 8 y e a r s w i t h no a n g i n a p a i n , c h a n c e o f p a i n t h e same a s i t i s now.  and a  A  If  or B  of I n d i f f e r e n t  you c h o s e A,  Treatment  C:  choose A  consider  100%  to A or B  the f o l l o w i n g  c h a n c e o f no p a i n  offer:  f o r 12  months,  or C  I f you c h o s e A, how many months need t o be a d d e d t o C t o g e t you to c h o o s e C? months I f you c h o s e C, how many months l e s s t h a n 12 w o u l d you accept to r e t a i n C? months If  you c h o s e B,  Treatment  choose B  D:  50% 50%  consider  the f o l l o w i n g  offer:  c h a n c e o f 5 y e a r s w i t h no a n g i n a p a i n , c h a n c e o f p a i n t h e same as i t i s now.  or D  I f you c h o s e B, what w o u l d t h e c h a n c e s i n D h a v e t o be t o g e t you to c h o o s e D? % I f you c h o s e D, how w o u l d t h e c h a n c e s i n D have t o change t o g e t you t o c h o o s e B?  14.To determine how many dollars you h a v e 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 y e a r o f r e t i r e m e n t , and make t h a t y o u r a n n u a l i n c o m e . Income = $ You a r e 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 . If other p o s i t i o n s on t h e l i s t were a v a i l a b l e , how much money w o u l d 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 w a i t t h e r e i s a 5% c h a n c e you m i g h t h a v e a h e a r t a t t a c k .  175 page 8 To  wait  3 months  To  wait  1 month  To  not w a i t  I would I would  trade trade  a t a l l I would  $  %)  $  %)  trade $  %)  15. You a r e 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 1 s t on t h e l i s t . W a i t i n g l o n g e r has a 5% c h a n c e 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 is available for everyone on t h e 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 t h a n you a r e .  How much money w o u l d you want f r o m t h e i f you w e r e t o w a i t 1 week? $ would If  you $  waited  3 months?  If  you $  waited  6 months?  person you  taking  your  place  trade?  16. C h o o s e b e t w e e n t h e 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 t r e a t m e n t : (Assume t h a t the treatment has s i d e e f f e c t s t h a t p r e v e n t t r y i n g another f o r at l e a s t 2 years) W h i l e you w a i t you b e a r 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 for 6 months), a f t e r pain for 4 years; Hospital years. A: B:  B:  No  time i s 6 months the treatment a l l  waiting  time,  ( a l l p a t i e n t s have p a t i e n t s have no  patients  h a v e no  angina  angina angina for 3  w a i t 6 months no w a i t  I f you c h o s e h o s p i t a l e l i m i n a t e d t o g e t you  A, how l o n g would t o c h o o s e B?  I f you chose h o s p i t a l B, how e l i m i n a t e d t o g e t you t o c h o o s e  l o n g would A?  angina  angina  pain  have to  be  p a i n have to  be  176 page 9 17. A f t e r a t r e a t m e n t f o r a n g i n a , some p a t i e n t s have p a i n t w i c e as o f t e n a s b e f o r e t h e t r e a t m e n t w h i l e some p a t i e n t s have no more p a i n . The numbers below a r e c h a n c e s t h a t t h e t r e a t m e n t w i l l c a u s e a n g i n a p a i n t o o c c u r t w i c e as o f t e n . W h i c h o f t h e s e g r o u p s would be a c c e p t a b l e t o you? pain  twice  as o f t e n  10% 30% 50% 70% 90%  PATIENT'S  c h a n c e o f no p a i n 90% 70% 50% 30% 10%  COMMENTS:  yes/no / / / / /  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%  10% ~§U%~  CHANCE OF SYMPTOMS OCCURING TWICE AS OFTEN AND CHANCE OF NO MORE SYMPTOMS  30% "75%"  50% "5W  70% 30%  180 Question  6 & 13  25% CHANCE OF 8 YEARS FREE FROM SYMPTOMS  181  Sensitivity  Analysis  for  Question  13  182  FOR 5 Y E A R S  183 Question  7 TREATMENT  A  TREATMENT  B  no symptoms  no symptoms  same symptoms  same symptoms die in hospital  80%  15%  TREATMENT  OVERLAY  5%  B.  60%  40%  184  estion  8 TREATMENT  A  TREATMENT  B  no symptoms  no symptoms  same symptoms  same symptoms die in hospital  75%  15%  TREATMENT  OVERLAY  15%  B.  die in hospital 55%  35%  10%  185  Question 9  TREATMENT A  TREATMENT B  10% Risk of Death  NO MORE SYMPTOMS FOR 6 YEARS  NO MORE SYMPTOMS FOR 5 YEARS  186  50% chance of complete freedom from symptoms.  50% chance of symptoms the same as now.  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