Aspirin and angiotensin-converting enzyme inhibitors among elderly survivors of hospitalization for an acute myocardial infarction

Background: Aspirin and angiotensin-converting enzyme (ACE) inhibitors are recommended for secondary prevention after acute myocardial infarction (AMI), but several studies have suggested that the combination of these medications may produce a negative interaction. Objective: To evaluate the effect and interaction of aspirin and ACE inhibitors on mortality among elderly patients who survived a hospitalization for AMI. Methods: We evaluated the effect and interaction of aspirin and ACE inhibitors on mortality in patients aged 65 years and older who survived hospitalization with a confirmed AMI who were ideal candidates for the therapies. Results: Among the 14129 patients, 26% received aspirin only, 20% received ACE inhibitors only, 38% received both, and 16% received neither at discharge. In the multivariate analysis, patients who received both aspirin and ACE inhibitors alone had a significantly lower 1-year mortality (adjusted risk ratio [ARR], 0.86 [95% confidence interval (CI), 0.78-0.95] vs 0.85 [95% CI, 0.77-0.93], respectively) compared with patients who received neither aspirin nor ACE inhibitors at discharge. Prescribing both aspirin and ACE inhibitors was associated with a slightly lower risk of mortality (ARR, 0.81; 95% CI, 0.74-0.88) than that seen in aspirin-only or ACE inhibitor-only groups, but the difference was not significantly different from the use of either medication alone. Conclusions: The benefit of ACE inhibitors and aspirin is consistent with what would be expected from overall results of randomized trials; prescribed together, the effect is slightly greater than with either one alone, but not significantly or substantially so.