[Does statin therapy reduce the risk of stroke? A meta-analysis]

Large scale clinical trials have clearly demonstrated that the HMG-CoA reductase inhibitors (statins) reduce cardiovascular mortality by about 30%. The specific benefit on stroke prevention remains however to be determined. We reviewed all controlled clinical trials comparing statins versus placebo in primary and secondary prevention of cardiovascular disease. We identified 13 studies including 4S, CARE, WOSCOPS and LIPID. More than 32000 patients were randomized. The meta-analysis was performed using relative risk as treatment effect parameter. Statin treatment induced a significant relative risk reduction (RRR) of 24% (95% CI [12%-34%]) for stroke (2.1% vs 2.8%). RRR achieved 25% (95% CI [17%-32%]) for cardiovascular mortality and 34% (95% CI [30%-38%]) for myocardial infarction, without heterogeneity between trials. Stroke was reduced by 25% in secondary prevention, and by 15% in primary prevention, without significant heterogeneity between them. RRR of stroke was similar with pravastatin (RRR=0.79, p=0.0038) and with simvastatin (RRR=0.71, p=0.049). The effect model analysis (relationship between annual incidence of events in treated group versus placebo group in each trial) showed that RRR was constant whatever the baseline risk. These results are in favor of a preventive efficacy of statin treatment against stroke in middle aged patients with coronary heart disease. Complementary information will be needed to clarify the mechanism of this beneficial effect and to demonstrate statin efficacy in a population with a higher risk of stroke such as the elderly.