Effectiveness of Simvastatin Versus Gemfibrozil for Primary Prevention of Cardiovascular Events: A Retrospective Cohort Study of 223,699 Primary Care Patients

Abstract

Background and Objective: Evidence of the effectiveness of statins compared with fibrates for primary prevention of cardiovascular events is limited. Therefore, we assessed the comparative effectiveness of simvastatin versus gemfibrozil for primary prevention of major adverse cardiovascular events (MACE) and mortality. Methods: This territory-wide cohort study used electronic health records of simvastatin and gemfibrozil prescriptions from the Hong Kong Hospital Authority and compared simvastatin or gemfibrozil initiation. The primary outcome was MACE, defined as the composite of the first diagnosis of cardiovascular mortality, coronary heart disease, or stroke. Secondary outcomes were the individual components of MACE, all-cause mortality, and non-cardiovascular mortality. Inverse probability of treatment weighting on the propensity score was used to estimate hazard ratios (HRs). Results: A total of 223,699 individuals (120,207 [53.7%] women; median follow-up 7.0 years [interquartile range 5.7–9.1]) who were prescribed simvastatin (n = 168,630) or gemfibrozil (n = 55,069) were included. Simvastatin was associated with a reduced risk of MACE (HR 0.90, 95% confidence interval [CI] 0.88–0.93), all-cause mortality (HR 0.88, 95% CI 0.86–0.90), cardiovascular mortality (HR 0.71, 95% CI 0.67–0.76), and non-cardiovascular mortality (HR 0.92, 95% CI 0.89–0.95). Associations for MACE varied according to baseline characteristics with gemfibrozil being associated with a reduced risk of MACE in men and patients with low baseline high-density lipoprotein (HDL) cholesterol (< 1.0 mmol/L). Conclusion: The results of this study showed better population-level effectiveness of simvastatin compared with gemfibrozil for the primary prevention of MACE; however, a definitive randomized controlled trial is required to compare simvastatin with gemfibrozil among patients with low HDL cholesterol, as they appear to obtain benefit with gemfibrozil.