Cost-effectiveness of aspirin treatment in the primary prevention of cardiovascular disease events in subgroups based on age, gender, and varying cardiovascular risk.

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.