Personalized Benefit and Harm of Aspirin for Primary Prevention

Study Questions:

Which patients without known cardiovascular disease (CVD) are most likely to experience net benefit from aspirin therapy for primary prevention?


The authors designed an individualized benefit–harm analysis using sex-specific risk scores to estimate proportional effects of aspirin therapy on preventing CVD and association with major bleeding. The authors analyzed a cohort of 245,028 people (ages 30-79 years) from New Zealand without known CVD between 2012 and 2016. Patients were followed for the development of CVD or major bleeding over 5 years of follow-up.


More men than women (12.1% and 2.5%, respectively) were likely to have net benefit from aspirin therapy for 5 years when one CVD event was assumed to be equivalent to one major bleeding event. If the weighting was changed where one CVD event was equivalent to two major bleeding events, significantly more men (40.7%) and women (21.4%) would derive net clinical benefit.


The authors concluded that some patients without CVD derive benefit of aspirin therapy for primary prevention.


Recent trials have questioned the benefit of routine aspirin use for primary prevention on CVD. This is due, in large part, to changes in other CVD risk factors (e.g., tobacco use, statin use) and the risk of major bleeding with aspirin therapy. These authors conducted a large-scale benefit-risk analysis of patients in a primary care setting without CVD in New Zealand. The proportion of patients who experience net clinical benefit from aspirin therapy varied greatly depending on the relative equivalent of preventing CVD events and avoiding major bleeding events. No matter which weighting is used (1:1 or 1:2), fewer than half of all patients ages 30-79 years without known CVD derive benefit from aspirin therapy for primary CVD prevention. Of note, prevention of cancer was not included in the analysis. In light of recent studies, routine use of aspirin for primary prevention should not be recommended. Rather, shared decision making that includes sex-specific assessment of CVD risk and incorporating patient values around avoiding CVD and bleeding events should guide the decision to use aspirin for primary CVD prevention.

Clinical Topics: Dyslipidemia, Prevention, Nonstatins, Novel Agents, Statins

Keywords: Aspirin, Cardiovascular Diseases, Hemorrhage, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Neoplasms, Primary Health Care, Primary Prevention, Risk Factors, Tobacco Use

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