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

BackgroundThe availability of generic simvastatin in 2006 has prompted substantial changes in formulary recommendations for lipid-management agents.ObjectiveTo 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.MethodsIn 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.ResultsWe identified 18,061 patients who, between September 1, 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.ConclusionsAmong 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.