In a recent study published in the American Journal of Cardiology, Zaatari et al conducted a study involving 7,057 patients enrolled in the OBTAIN multicenter registry of patients with acute MI; 4,142 patients were discharged on metoprolol and 1,487 on carvedilol. The Kaplan-Meier method was used to calculate 3-year survival, and correction for baseline differences was achieved by multivariable adjustment. The researchers indicated that patients treated with carvedilol were older (age 64.4 years vs. age 63.3 years) and had more comorbidities: hypertension, diabetes, prior MI, congestive heart failure, reduced LVEF, and a longer length of stay.
The average doses for metoprolol and carvedilol did not vary substantially (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 hazard ratio (HR) = 0.72 (P <.0001), but after multivariable adjustment, HR = 1.073 (P = .43). Patients in the >12.5% to 25% dose category had enhanced survival compared with other dose categories. Subgroup analysis of patients with LVEF ≤40% demonstrated worse survival with metoprolol versus carvedilol (adjusted HR = 1.281; 95% CI, 1.024-1.602; P = .03). In patients with LVEF >40%, there were no differences in survival with carvedilol versus metoprolol.
The researchers concluded that the overall survival after acute MI was comparable for patients treated with metoprolol compared with carvedilol. The authors noted that the findings from this study indicate that outcomes with carvedilol may be superior to metoprolol only in patients with LVED ≤40%. Researchers also noted that further validation of these findings with prospective trials is necessary.
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