PCV5 Pharmaceutical Costs of Patient Non-Adherence to Lipid-Lowering Drug Therapy

Lipid-lowering (LL) drugs decrease morbidity and mortality due to coronary heart disease (CHD). Among CHD patients, some LL drugs also decrease overall mortality. To realize the therapeutic benefits, LL drugs must be used for at least two years. A previous study in Saskatchewan showed that patient adherence to LL drugs is poor. OBJECTIVES: The objective of this study is to quantify the direct costs of non-adherence to LL drug therapy. The first phase will focus on pharmaceutical costs. Subsequent analyses will include physician services and hospitalization costs. METHODS: The government of Saskatchewan maintains comprehensive, linkable databases on health services provided to the population of approximately one million residents. Eligible beneficiaries with one or more outpatient prescriptions for LL drugs between 1989 and 1996 were identified. Exposure time was calculated for each subject. Cost analyses were conducted from the societal perspective. RESULTS: LL drugs were commonly used in Saskatchewan during the study period: 629,728 prescriptions for LL drugs were dispensed to 32,758 people (approximately 3% of the population). Statins were the most widely used LL drugs, followed by gemfibrozil and cholestyramine. On average, subjects were exposed to LL drugs for 1.7 years. Only 35% of LL drug users were exposed for two years or longer. The total cost of LL prescriptions during the study period was $44.6 million CAN. However, $6.9 million (15%) of these costs were for prescriptions dispensed to people who used LL drugs for less than two years. DISCUSSION: Poor patient adherence to LL drugs results in substantial wastage of pharmaceutical expenditures. Future analyses will focus on outcomes associated with non-adherence and their impact on overall physician service, hospitalization and drug costs.