Impact of acute beta-blocker therapy for patients with non-ST-segment elevation myocardial infarction

Early use of beta-blockers is a quality indicator for the treatment of patients with non-ST-segment elevation myocardial infarction (NSTEMI), despite limited data from randomized clinical trials in this population. We sought to determine the impact of acute beta-blocker therapy on outcomes in patients with NSTEMI.

We examined acute (<24 hours) beta-blocker use in 72,054 patients with NSTEMI from the Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the American College of Cardiology/American Heart Association Guidelines (CRUSADE) initiative at 509 US hospitals from 2001-2004. We analyzed patient and provider factors associated with beta-blocker use and the impact of beta-blocker therapy on unadjusted, risk-adjusted, and propensity matched outcomes in the overall sample and among selected high-risk subgroups.

A total of 82.5% of patients without documented contraindications received acute beta-blocker therapy. Factors strongly associated with acute beta-blocker use included prior beta-blocker use, higher presenting systolic blood pressure, lower heart rate, lack of signs of heart failure, and cardiology care. Acute beta-blocker use was associated with lower in-hospital mortality (unadjusted 3.9% vs 6.9%, P <.001, adjusted odds ratio 0.66, 95% confidence interval 0.60-0.72), lower adjusted mortality among most of 6 subgroups determined by propensity to receive acute beta-blockers, and lower adjusted mortality in patients with and without signs of heart failure and in those <80 years and those > or =80 years old.

The majority of NSTEMI patients receive acute beta-blocker therapy. Certain patient subgroups remain undertreated. Because treatment with acute beta-blockers was associated with improved clinical outcomes in nearly all patient subgroups assessed, broader use in patients with NSTEMI appears warranted.