Background: Angiotensin-converting enzyme (ACE) inhibitors and angiotensin-II receptor blockers (ARBs) are used for similar indications. ACE inhibitors have demonstrated reductions in cardiovascular morbidity and mortality, and are used to prevent nephropathy and treat hypertension. One advantage of ARBs is that they do not produce cough, an adverse effect of ACE inhibitors that occurs in less than 10 percent of all patients and in less than 5 percent of patients when compared with controls. Winkelmayer and colleagues performed a head-to-head comparison of ACE inhibitors and ARBs in terms of effectiveness and mortality outcomes after myocardial infarction.
The Study: The authors used claims data from four drug entitlement programs to find patients discharged from the hospital after myocardial infarction. Patients who were released from the hospital within 30 days and survived at least 90 days were included in the study. Sex, age, race, comorbid conditions, and health care usage indicators were abstracted from the claims data. Data about filled prescriptions also were obtained.
Results: Of the 43,416 postmyocardial infarction patients participating in one of the drug entitlement programs, 14,612 were eligible and had filled a prescription for an ACE inhibitor or an ARB within 90 days after admission, and 422 filled a prescription for both medications.
Over the 10-year study, an increasing proportion of new patients received only an ARB, with 17.6 percent receiving a new prescription in 2004, up from 2.7 percent at the beginning of the study. Of the group using ACE inhibitors, ARBs, or both, 16.1 percent died within one year of experiencing a myocardial infarction. The difference between ACE inhibitor and ARB users who died was not significant: one-year mortality was no different after univariate analysis (hazard ratio [HR], 0.92; 95% confidence interval [CI], 0.80 to 1.05) or multivariate analysis (HR, 1.04; 95% CI, 0.88 to 1.22).
Conclusion: The authors found that ARB use after myocardial infarction increased over the course of the study but with no additional health benefit. All-cause mortality was similar regardless of whether the patients were taking an ACE inhibitor or an ARB. This is similar to the findings in two randomized trials, which also showed no difference between drug classes, and, of note, no benefit from taking an ACE inhibitor and an ARB simultaneously. Because the percent-age of persons on ARBs greatly exceeded the expected percentage of patients with a cough from an ACE inhibitor, this was likely not the reason for the increased use of ARBs. Eighteen percent of postmyocardial infarction patients on ARBs had never used ACE inhibitors. Together with those who switched from or used combinations including ACE inhibitors, the percentage of patients taking ARBs represents overuse of this class of drugs. ACE inhibitors should be the first-line drugs after myocardial infarction, and the much more expensive, but no more effective, ARBs should be reserved for patients with cough or angioedema related to ACE inhibitors.