A Retrospective Cohort Study of Correlates of Response to Pharmacologic Therapy for Hyperlipidemia in Members of a Managed Care Organization

Background: Few studies have examined the effectiveness of statins in a managed care setting. Objective: The aim of this study was to identify demographic, clinical, and pharmacotherapy-related factors associated with response to drug therapy for hyperlipidemia among members of a managed care organization. Methods: Claims data from a large US managed care organization from July 1, 1998, through June 30, 2000, were analyzed for adult members with continuous enrollment, ≥1 prescription drug claim, ≥2 sets of fasting low-density lipoprotein cholesterol (LDL-C) laboratory results, and no lipid-lowering prescription claims at any time ≤12 months before the date of the first set of LDL-C laboratory results. Relative lipid-lowering regimen efficacy categories were created based on percentage reduction in LDL-C listed in product package inserts (low, ≤30%; moderate, 31%-40%; high, ≥41%). Multiple regression and logistic regression models were developed to identify significant predictors of percentage change in LDL-C from baseline and of ≥10% reduction in LDL-C. Results: A total of 6247 members met the inclusion criteria. The mean (SD) age was 59.6 (12.4) years (range, 21-93 years), and 3003 individuals (48.1%) were women. Furthermore, 337 members (5.4%) received high-efficacy statins, 2633 (42.1%) received moderate-efficacy statins, 934 (15.0%) received low-efficacy statins, and 86 (1.4%) received low-efficacy lipid-lowering drugs from other therapeutic classes during the study period. Compliance with therapy was high (range, 85%-92%), and upward titration of therapy was found in only 160 members (2.6%). Multiple regression analysis indicated that receiving statin therapy compared with other lipid-lowering therapy was a significant predictor of percentage reduction in LDL-C (P < 0.001). Logistic regression analysis indicated that compared with high-efficacy statin regimens, low-efficacy statin regimens (odds ratio [OR] = 0.619; 95% CI, 0.436-0.877) and low-efficacy regimens from other therapeutic classes (OR = 0.171; 95% CI, 0.099-0.295) were less effective in lowering LDL-C by ≥10%. Similar results were observed for subanalyses of subjects with diabetes mellitus or coronary heart disease (CHD); individuals who received more efficacious statin regimens were more likely to reach the National Cholesterol Education Program Adult Treatment Panel II LDL-C goal of ≤100 mg/dL (P < 0.05 for moderate- or low-efficacy regimens vs high-efficacy statins in each model). Conclusion: The results of the present study suggest that improvement is needed in hyperlipidemia management, especially in identification and use of lipid-lowering therapy in individuals at high risk for CHD.