Impact of statins on risk of stroke: A meta-analysis

BACKGROUND: Evidence from randomized, controlled trials suggests that reduction of low-density lipoprotein cholesterol with hydroxymethylglutaryl coenzyme A reductase inhibitor (statin) therapy in patients at high risk for cardiovascular disease reduces the incidence of ischemic stroke; however, data from large epidemiologic observational studies suggest an inverse relationship between risk of hemorrhagic stroke and cholesterol levels. OBJECTIVE: To perform a meta-analysis of randomized controlled trials to assess the effect of statin therapy on all cerebrovascular events (CVEs), ischemic stroke, and hemorrhagic stroke. METHODS: A systematic literature search of MEDLINE, EMBASE, Cumulative Index to Nursing & Allied Health Literature, and Web of Science citations from June 1975 through September 2006 was performed to identify randomized controlled trials of statin therapy. Trials were included if they met the following criteria: (1) controlled clinical trials of statin therapy versus placebo, (2) well-described protocol, and (3) data reported on incidence of all CVEs, ischemic stroke, or hemorrhagic stroke. All data were independently extracted by 3 investigators. RESULTS: Weighted averages are reported as relative risk with 95% confidence intervals. A total of 26 trials (N = 100,560) reported incidence on all CVEs. Six trials (n = 37,292) reported incidence of ischemic stroke and 9 trials (n = 57,895) were included in the hemorrhagic stroke analysis. Statin therapy significantly reduced the risk of all CVEs (RR 0.83; 95% Cl 0.76 to 0.91) and the risk of ischemic stroke (RR 0.79; 95% C1 0.63 to 0.99). Statin therapy did not significantly reduce risk of hemorrhagic stroke (RR 1.11; 95% Cl 0.77 to 1.60). CONCLUSIONS: Statin therapy significantly reduces risk of developing all CVEs and ischemic stroke; however, it is associated with a nonsignificant increase in risk of hemorrhagic stroke.