Aspirin for the Primary Prevention of Cardiovascular Disease: Weighing Up the Evidence

Aspirin is one of the most universally recognized and commonly prescribed medications worldwide. It is estimated that 48.7 million U.S. adults are taking aspirin for cardiovascular disease prevention; the majority (~73%) for primary prevention.1 The benefit of aspirin for secondary prevention of cardiovascular disease is well-established, with meta-analysis results favoring low dose (75–150mg/day) over high dose (>150mg/day) aspirin given similar efficacy but lower bleeding risk. In contrast, the role of aspirin in primary cardiovascular disease prevention is more controversial; historical trials found benefit2 but trials since 2008 have shown either null effects on all-cause and cardiovascular disease mortality2–4 or a signal for increased mortality in the context of excess bleeding.