Clinical Question: In patients with or without heart disease, does lipid lowering decrease stroke risk?

Setting: Outpatient (any)

Study Design: Meta-analysis (randomized controlled trials)

Synopsis: The authors of this meta-analysis set out to determine whether lipid lowering of any kind decreases the likelihood of stroke in patients with or without coronary heart disease. They started by identifying 65 randomized controlled trials that compared any intervention with placebo or usual diet; a total of 200,607 patients were included. They conducted the appropriate search of five databases, including articles in all languages, and they searched reference lists. Two investigators independently assessed the quality of the studies and evaluated any possible influence on the results.

As has been shown previously, treatment with a statin decreased fatal and nonfatal stroke risk by approximately 25 percent in patients with or without coronary heart disease (primary and secondary prevention). For patients at low risk (0.2 percent likelihood per year in these studies), this benefit translated into one fewer stroke for every 2,778 patients treated for one year (95 percent confidence interval [CI], 2,083 to 5,000). For those at high risk (0.9 percent per year), the benefit was one fewer stroke for every 617 patients treated for one year (95 percent CI, 463 to 1,111). The benefit was not quite as pronounced in the studies that used concealed allocation when enrolling patients. Treatment with other cholesterol-lowering approaches, including diet, did not have an effect on stroke risk.

Bottom Line: Statins produce a statistically significant reduction of 25 percent on average in the risk of experiencing a fatal or nonfatal stroke. Other approaches to lipid lowering do not. However, physicians need to realize that this reduction translates into one fewer stroke in every 2,778 patients at low risk (i.e., without heart disease) and one fewer stroke for every 617 patients with preexisting heart disease. (Level of Evidence: 1a)