UBC Theses and Dissertations
Assessment of the appropriate treatment of coronary artery disease and dyslipidaemia in an angiographically defined patient population Francis, Michelle Catherine
Cardiovascular disease is the leading cause of death in British Columbia and Canada, with the majority of cases being the result of coronary artery disease (CAD). CAD is a result of the interaction between genetic background and environmental influence. Several modifiable and non-modifiable risk factors contribute to the development and progression of atherosclerosis - the major cause of CAD. Numerous studies have shown that treatment of CAD risk factors, and dyslipidaemia in particular, reduces the incidence of CAD morbidity and mortality. Based on this evidence, national guidelines have been published for the treatment of dyslipidaemia and management of other risk factors of CAD. However, examination o f treatment practices in Canada, the US, and Europe has shown sub-optimal adherence to these guidelines. This thesis describes a questionnaire-based follow-up of consecutive patients referred for selective coronary angiography (SCA) between 1993 and 1995 at two tertiary Vancouver hospitals. Lipid measurements, risk factor prevalence, and medication use at the time of SCA were available for all patients. The follow-up assessed changes in risk factors and medications, incidence of CAD morbidity, access to risk factor counseling, patient awareness of risk factors, and, in the case of deceased patients, cause of death. The 1988 Canadian Consensus Conference on Cholesterol (CCCC) and 1993 National Cholesterol Education Program (NCEP) guidelines were used to determine the appropriate treatment of dyslipidaemia in those who responded to the questionnaire. Respondents were more likely to have CAD, less likely to smoke, and more likely to live in rural areas than non-respondents. The prevalence of most risk factors was comparable to previous reports, however respondents were more obese and had a greater number of risk factors than the Canadian population. Between 1993 and 1997, 150 patients died, with cause of death available for 102. Of these, 70% died of cardiovascular causes. Awareness of risk factors was less than ideal among respondents. Only half were able to correctly judge their change in weight and exercise. Just over half knew their blood pressure, while only two-fifths could report their cholesterol level. Counseling for lifestyle risk factors was under-utilised in general, although appeared well targeted to patients requiring intervention. While the number of patients who would have required cholesterol monitoring, dietary therapy, or drug intervention differed between guidelines, the prevalence of appropriate dyslipidaemia treatment was equivalent regardless of the guideline employed. Three-quarters of respondents requiring cholesterol monitoring had their lipids checked during the follow-up period. Dietary therapy was appropriately administered in approximately 70% of patients requiring treatment. However, counseling by dieticians, which is explicitly required by CCCC guidelines, was seen in only 38%. Lipid lowering drugs (LLD) were not prescribed for over 40% of respondents requiring drug therapy. While the number of patients being treated appropriately for their dyslipidaemia was found to be slightly higher in the study population than in other studies published in the literature, the level of treatment was still sub-optimal, particularly with respect to utilisation of allied health professionals. With cardiovascular disease being the leading cause of death in British Columbia, more effort must be made to follow established guidelines using well-proven methods of treatment.
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