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

Abstract

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 14 129 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.