The aspirin controversy in primary prevention

Purpose of review Apparently conflicting meta-analysis results have led to renewed debate about the role of aspirin for the primary prevention of cardiovascular disease. We review the results of meta-analyses comparing aspirin with placebo or no aspirin for the primary prevention of cardiovascular disease and critically evaluate whether aspirin provides a net benefit. Recent findings The results of four independently conducted meta-analyses between 2009 and 2012 involving between 95 000 and 102 621 individuals at low risk of cardiovascular disease are consistent with the results of the 2002 Antithrombotic Trialists' Collaboration meta-analysis, which found that aspirin reduces cardiovascular events primarily by reducing nonfatal myocardial infarction (MI). There is no convincing evidence that aspirin reduces cardiovascular mortality, but estimates from all of the meta-analyses suggest a modest reduction in all-cause mortality. Aspirin reduces ischaemic stroke but increases haemorrhagic stroke and major bleeding. Summary The meta-analysis results consistently indicate that, in individuals at low risk for cardiovascular disease, aspirin reduces the risk of MI at the cost of an increase in major bleeding and produces a modest nominally significant reduction in total mortality. These results suggest that recommendations for primary prevention with aspirin should be individualized, taking into account the balance between benefits and risks and individual values and preferences.