Initiation of statins and risk of venous thromboembolism: Population-based matched cohort study

Abstract

BackgroundThe effects of statins in prevention of venous thromboembolism (VTE) is not well established. ObjectivesTo examine the risks of first-time VTE in a cohort of patients initiating statin treatment and in a matched general population comparison cohort. MethodsWe conducted a nationwide, population-based, matched cohort study based on data from Danish health registries. The study period was 1 January 2005–31 December 2015. We identified statin initiators (without VTE, myocardial infarction, or ischemic stroke) and sex-, age-, and calendar year-matched (1,3) individuals from the general population (without statin use, VTE, myocardial infarction, or ischemic stroke). We computed cumulative risks and comorbidity-adjusted hazard ratios (HRs) of VTE, myocardial infarction, and ischemic stroke. ResultsAmong 601,011 statin initiators and 1,803,033 matched population cohort members during 2005–2015, the cumulative risk after 11 years was 2.8% for VTE (both cohorts), 4.7% vs. 2.9% for myocardial infarction, and 7.1% vs. 5.2 for ischemic stroke. After adjustment, statin use was associated with a slightly decreased risk of VTE (adjusted HR: 0.95 [95% CI: 0.92–0.97]), driven by a reduced risk of unprovoked VTE (adjusted HR: 0.92 [95% CI: 0.89–0.95]). The reduced risks of VTE were more pronounced among patients who had an imaging examination performed. The adjusted HRs were elevated for myocardial infarction and ischemic stroke. ConclusionStatin initiation was associated with a reduced risk of VTE, with no indication of a healthy-user effect. Based on available evidence, statins have weak thromboprophylactic effects.