Switching from high-efficacy lipid-lowering therapies to simvastatin and low-density lipoprotein cholesterol goal attainment in coronary heart disease/coronary heart disease-equivalent patients

BACKGROUND: The availability of generic simvastatin in 2006 has prompted substantial changes in formulary recommendations for lipid-management agents. OBJECTIVE: To assess the impact of switches from high-efficacy lipid-lowering therapy to simvastatin on low-density lipoprotein cholesterol (LDL-C) and goal attainment in coronary heart disease (CHD) or CHD risk-equivalent patients in a managed care setting. METHODS: In this retrospective observational study, we estimated the least squares mean difference in the percent change from baseline LDL-C and the odds ratios for LDL-C goal attainment rates (<100 mg/dL and <70 mg/dL) at follow-up for each baseline high-efficacy lipid-lowering therapy with the analysis of covariance and logistic regressions, respectively. RESULTS: We identified 18,061 patients who, between September I, 2004 and October 31, 2008, were either switched from or remained on their initial high-efficacy LDL-C lowering therapy: ezetimibe/simvastatin fixed-dose combination (E/S), rosuvastatin, or atorvastatin. The difference in percent change in LDL-C levels from baseline were 25.2(95% confidence interval 21.2-29.2), 13.0 (6.0-20.0), and 3.1 (0.3-5.9) greater in switchers to simvastatin in the E/S, rosuvastatin, and atorvastatin comparisons, respectively, after adjusting for age, sex, and starting dose of the initial therapy. For switchers, the percent of patients at LDL-C <100 mg/dL at follow-up decreased from 83.5% to 63.8% in the E/S, 67.7% to 52.7% in the rosuvastatin, and 65.1% to 60.2% in the atorvastatin cohorts. The percent of patients at LDL-C <70 mg/dL at follow-up was lower for all switcher groups compared with nonswitchers. CONCLUSIONS: Among CHD/CHD risk-equivalent patients, switching to simvastatin was associated with increases in LDL-C levels and lower LDL-C goal attainment rates. The public health impact of this phenomenon on population risk and CHD events remains to be determined. (C) 2010 National Lipid Association. All rights reserved.