Clinical Inquiries: What are the benefits and risks of daily low-dose aspirin for primary prevention of CV events?

One nonfatal myocardial infarction (MI) will be avoided for every 126 to 138 adults who take daily aspirin for 10 years (strength of recommendation [SOR]: A, systematic reviews and meta-analyses of multiple randomized controlled trials [RCTs]). Taking low-dose aspirin for primary prevention shows no clear mortality benefit. A benefit for primary prevention of stroke is less certain. Although no evidence establishes increased risk of hemorrhagic stroke from daily low-dose aspirin, one gastrointestinal hemorrhage will occur for every 72 to 357 adults who take aspirin for longer than 10 years (SOR: A, systematic reviews and meta-analyses of multiple RCTs and cohort studies).