Comparison of Metoprolol Versus Carvedilol After Acute Myocardial Infarction

Beta-blockers are typically prescribed following myocardial infarction (MI), but no specific beta-blocker is recommended. Of 7,057 patients enrolled in the OBTAIN multi-center registry of patients with acute MI, 4142 were discharged on metoprolol and 1487 on carvedilol. Beta-blocker dose was indexed to the target daily dose used in randomized clinical trials (metoprolol-200 mg; carvedilol-50 mg), reported as %. Beta-blocker dosage groups were >0% to12.5% (n = 1,428), >12.5% to 25% (n = 2113), >25% to 50% (n = 1,392), and >50% (n = 696). The Kaplan-Meier method was used to calculate 3-year survival. Correction for baseline differences was achieved by multivariable adjustment. Patients treated with carvedilol were older (64.4 vs 63.3 years) and had more comorbidities: hypertension, diabetes, prior MI, congestive heart failure, reduced left ventricular ejection fraction, and a longer length of stay. Mean doses for metoprolol and carvedilol did not significantly differ (37.2 ± 27.8% and 35.8 ± 31.0%, respectively). The 3-year survival estimates were 88.2% and 83.5% for metoprolol and carvedilol, respectively, with an unadjusted HR = 0.72 (p <0.0001), but after multivariable adjustment HR = 1.073 (p = 0.43). Patients in the >12.5% to 25% dose category had improved survival compared with other dose categories. Subgroup analysis of patients with left ventricular ejection fraction ≤40%, showed worse survival with metoprolol versus carvedilol (adjusted HR = 1.281; 95% CI: 1.024 to 1.602, p = 0.03). In patients with left ventricular ejection fraction >40%, there were no differences in survival with carvedilol versus metoprolol. In conclusion, overall survival after acute MI was similar for patients treated with metoprolol or carvedilol, but may be superior for carvedilol in patients with left ventricular ejection fraction ≤40%.