Background—Aspirin is effective for the primary prevention of cardiovascular events, but it remains unclear for which subgroups of individuals aspirin is beneficial. We assessed the cost-effectiveness of aspirin separately for men and women of different ages with various levels of cardiovascular disease risk.

Methods and Results—A Markov model was developed to predict the number of cardiovascular events prevented, quality-adjusted life-years, and costs over a 10-year period. Event rates were taken from Dutch population data, and the relative effectiveness of aspirin was taken from a gender-specific meta-analysis. Sensitivity analyses and Monte Carlo simulations were conducted to evaluate the robustness of the results. In 55-year-old persons, aspirin prevented myocardial infarctions in men (127 events per 100 000 person-years) and ischemic strokes in women (17 events per 100 000 person-years). Aspirin implies a net investment and a quality-adjusted life-year gain in men 55 years of age; the incremental cost-effectiveness ratio was 111 949 euros per quality-adjusted life-year (1 euro=$1.27 as of June 2007). Aspirin was cost-effective for 55- and 65-year-old men with moderate cardiovascular risk and men 75 years of age (10-year cardiovascular disease risk >10%). Conversely, aspirin was beneficial for women 65 years of age with high cardiovascular risk and women 75 years of age with moderate cardiovascular risk (10-year cardiovascular disease risk >15%). Results were sensitive to drug treatment costs, effectiveness of aspirin treatment, and utility of taking aspirin.

Conclusions—Aspirin treatment for primary prevention is cost-effective for men with a 10-year cardiovascular disease risk of >10% and for women with a risk of >15%. This occurs much later in life for women than men. Therefore, opportunities for the primary prevention of aspirin seem limited in women, and a differentiated preventive strategy seems warranted.