Prevalence and treatment of dyslipidemia in Canadian primary care: a retrospective cohort analysis

Abstract

Background: Dyslipidemia is an important modifiable risk factor for cardiovascular disease (CVD). Studies suggest that dyslipidemia is underdiagnosed and undertreated in Canada.

Objective: The objective of this study was to describe dyslipidemia prevalence, patient characteristics, and lipid-lowering treatment (LLT) patterns in a cohort representing Canadian primary care practice.

Methods: In this retrospective cohort analysis, the Southwestern Ontario database (which comprises data from >150,000 adult patients in rural and urban primary care practices) was used as the data source. Male and female patients with data available from 4 physician visits were included; data were captured quarterly between April 2000 and December 2003 and included demographic and lifestyle information, CVD risk factors, and cardiovascular drug treatments. Data gathered included clinical diagnoses at each visit, symptoms corroborating the diagnoses, clinical data (eg, blood pressure, smoking status, height, weight, fitness level), medications (including name, dose, duration, and quantity prescribed), and diagnostic test results and laboratory analyses. For the purposes of this study, a patient was considered to have dyslipidemia if >/=1 of the following conditions was met: (1) physician-diagnosed hyperlipidemia or hypercholes terolemia; (2) at least 1 measurement of low-density lipoprotein cholesterol (LDL-C) or total cholesterol: high-density lipoprotein cholesterol (TC:HDL-C) ratio greater than the recommended targets based on 10-year coronary artery disease (CAD) risk; and/or (3) at least 1 prescription for a lipid-lowering drug.

Results: A total of 49,667 patients were included in the study cohort. Dyslipidemia was identified in 6961 (14.0%) patients. Of patients with dyslipidemia, more were untreated (63.2%) than treated (36.7%) with LLTs, with women receiving treatment less often than men (P < 0.001). Of those treated, 47.2% had disease that was not adequately controlled, with fewer treated women having controlled disease than treated men (P < 0.017). Patients with dyslipidemia fell mostly into very-high-risk (45.7%) or low-risk (31.1 %) categories for CAD. A total of 73.0% of treated patients were prescribed monotherapy with a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin); of starin prescriptions, most were for atorvastatin (51.8%) or simvastatin (29.4%). Initial LDL-C levels and initial TC:HDL-C ratios were statistically similar between patients prescribed atorvastatin and those prescribed simvastatin.

Conclusion: Based on the results of this retrospective cohort analysis, dyslipidemia prevalence in Canadian primary care is high, and despite clinical evidence and treatment guidelines, dyslipidemia is largely untreated in family practice, suggesting a gap in care.