Background: We conducted an historical cohort study to evaluate the relative effectiveness of niacin and lovastatin in the treatment of dyslipidemias in patients enrolled in a health maintenance organization (HMO).
Methods: To be eligible for this study, adults aged 18 years and older who were initially treated with either niacin or lovastatin between January 1, 1992, and December 31, 1993, were identified from pharmacy databases. Each potentially eligible member with a fasting lipid panel prior to initiation of drug therapy and with a second fasting lipid panel between 9 and 15 months after initiation of drug therapy was included in the study. A total of 244 patients treated with niacin and 160 patients treated with lovastatin had complete data and are subjects of this report.
Results: Patients initially treated with lovastatin had higher baseline mean cholesterol and low-density lipoprotein (LDL) levels as well as higher rates of diabetes mellitus and heart disease than did patients initially treated with niacin. Lovastatin use was associated with a mean 25.8% decrease in LDL cholesterol, while niacin use was associated with a mean 17.5% drop in LDL cholesterol (t = 3.19, P < .002). Niacin use was associated with a 16.3% improvement in high-density lipoprotein (HDL) cholesterol, while HDL-cholesterol levels in the lovastatin group improved 1.5% (t = 4.74, P < .001). Niacin use was associated with an 18.4% improvement in triglycerides, while lovastatin use was associated with an 8% improvement in triglyceride levels (t = 2.81, P = .005). Differences in LDL/HDL ratio from before treatment to follow-up were no different in the two groups of patients (t = -1.21, P = .22). A total of 46% of patients initially treated with either drug reached their treatment goals in accordance with those set by the National Cholesterol Education Program. Drug discontinuation rates were 73% for niacin and 52% for lovastatin at follow-up, which averaged 10.7 months in each group.
Conclusions: These results suggest that both niacin and lovastatin are effective in treating dyslipidemic patients in this care system, and that physicians appropriately use lovastatin more often for patients with higher baseline LDL levels and more comorbidity. The data also strongly suggest that establishing an organized, population-based approach to systematically identify, treat, and monitor patients with dyslipidemias may be the single most important intervention HMOs should consider for improving control of dyslipidemias on a population basis.