Clinical outcomes with β-blockers for myocardial infarction: a meta-analysis of randomized trials

Am J Med. 2014 Oct;127(10):939-53. doi: 10.1016/j.amjmed.2014.05.032. Epub 2014 Jun 11.

Abstract

Background: Debate exists about the efficacy of β-blockers in myocardial infarction and their required duration of usage in contemporary practice.

Methods: We conducted a MEDLINE/EMBASE/CENTRAL search for randomized trials evaluating β-blockers in myocardial infarction enrolling at least 100 patients. The primary outcome was all-cause mortality. Analysis was performed stratifying trials into reperfusion-era (> 50% undergoing reperfusion or receiving aspirin/statin) or pre-reperfusion-era trials.

Results: Sixty trials with 102,003 patients satisfied the inclusion criteria. In the acute myocardial infarction trials, a significant interaction (Pinteraction = .02) was noted such that β-blockers reduced mortality in the pre-reperfusion (incident rate ratio [IRR] 0.86; 95% confidence interval [CI], 0.79-0.94) but not in the reperfusion era (IRR 0.98; 95% CI, 0.92-1.05). In the pre-reperfusion era, β-blockers reduced cardiovascular mortality (IRR 0.87; 95% CI, 0.78-0.98), myocardial infarction (IRR 0.78; 95% CI, 0.62-0.97), and angina (IRR 0.88; 95% CI, 0.82-0.95), with no difference for other outcomes. In the reperfusion era, β-blockers reduced myocardial infarction (IRR 0.72; 95% CI, 0.62-0.83) (number needed to treat to benefit [NNTB] = 209) and angina (IRR 0.80; 95% CI, 0.65-0.98) (NNTB = 26) at the expense of increase in heart failure (IRR 1.10; 95% CI, 1.05-1.16) (number needed to treat to harm [NNTH] = 79), cardiogenic shock (IRR 1.29; 95% CI, 1.18-1.41) (NNTH = 90), and drug discontinuation (IRR 1.64; 95% CI, 1.55-1.73), with no benefit for other outcomes. Benefits for recurrent myocardial infarction and angina in the reperfusion era appeared to be short term (30 days).

Conclusions: In contemporary practice of treatment of myocardial infarction, β-blockers have no mortality benefit but reduce recurrent myocardial infarction and angina (short-term) at the expense of increase in heart failure, cardiogenic shock, and drug discontinuation. The guideline authors should reconsider the strength of recommendations for β-blockers post myocardial infarction.

Keywords: Myocardial infarction; Outcomes; Reperfusion; β-blockers.

Publication types

  • Meta-Analysis

MeSH terms

  • Adrenergic beta-Antagonists / administration & dosage
  • Adrenergic beta-Antagonists / adverse effects
  • Adrenergic beta-Antagonists / therapeutic use*
  • Cause of Death
  • Comorbidity
  • Databases, Bibliographic
  • Heart Failure / epidemiology
  • Humans
  • Myocardial Infarction / drug therapy*
  • Myocardial Infarction / mortality
  • Myocardial Infarction / therapy
  • Myocardial Reperfusion / statistics & numerical data*
  • Randomized Controlled Trials as Topic
  • Shock, Cardiogenic / epidemiology
  • Time Factors
  • Treatment Outcome*

Substances

  • Adrenergic beta-Antagonists