The cost-effectiveness of aspirin for primary prevention of cardiovascular events in women is unclear. We sought to perform a cost-utility analysis to address this issue.Methods
We developed a Markov model, based on published literature, to compare aspirin prevention with no therapy. We used the perspective of a third-party payer and a lifetime time horizon. Our main outcome measure was cost per quality-adjusted life-year (QALY) gained. Our base case analysis considered 65-year-old women with a 7.5% 10-year risk of coronary heart disease events and a 2.8% risk of stroke.Results
Aspirin use cost $13 300 per additional QALY gained in the base case. Results were sensitive to age, cardiovascular disease risk, relative risk reductions with aspirin for ischemic strokes and myocardial infarction, excess risk of hemorrhagic stroke and gastrointestinal bleeding, and the disutility of taking medication. Probabilistic sensitivity analysis for 65-year-old women at moderate cardiovascular disease risk found a 27% chance that aspirin produces fewer QALYs than no treatment, a 35% chance that the cost-utility ratio was less than $50 000 per QALY gained, and a 37% probability that it was greater than $50 000 per QALY gained.Conclusions
Aspirin use appears to have a favorable cost-utility ratio for older women with moderate cardiovascular risk, but firm conclusions about its effects are limited by the imprecision of available evidence, which comes mainly from 1 trial. Aspirin is indicated for women at higher risk for stroke but should not be prescribed for low-risk women, including most younger women.