Does the early administration of beta-blockers improve the in-hospital mortality rate of patients admitted with acute coronary syndrome?

OBJECTIVES

Beta-blockade is currently recommended in the early management of patients with acute coronary syndromes (ACS). This was a systematic review of the medical literature to determine if early beta-blockade improves the outcome of patients with ACS.

METHODS

The authors searched the PubMed and EMBASE databases for randomized controlled trials from 1965 through May 2009 using a search strategy derived from the following PICO formulation of our clinical question: Patients included adults (18+ years) with an acute or suspected myocardial infarction (MI) within 24 hours of onset of chest pain. Intervention included intravenous or oral beta-blockers administered within 8 hours of presentation. The comparator included standard medical therapy with or without placebo versus early beta-blocker administration. The outcome was the risk of in-hospital death in the intervention groups versus the comparator groups. The methodologic quality of the studies was assessed. Qualitative methods were used to summarize the study results. In-hospital mortality rates were compared using a forest plot of relative risk (RR; 95% confidence interval [CI]) between beta-blockers and controls. Statistical analysis was done with Review Manager V5.0.

RESULTS

Eighteen articles (total N = 72,249) met the inclusion/exclusion criteria. For in-hospital mortality, RR = 0.95 (95% CI, 0.90-1.01). In the largest of these studies (n = 45,852), a significantly higher rate (p < 0.0001) of cardiogenic shock was observed in the beta-blocker (5.0%) versus control group (3.9%).

CONCLUSIONS

This systematic review failed to demonstrate a convincing in-hospital mortality benefit for using beta-blockers early in the course of patients with an acute or suspected MI.