β-blocker and clinical outcomes in patients after myocardial infarction: a systematic review and meta-analysis.

Background and objective: While current clinical guidelines generally advocate for beta-blocker therapy following acute myocardial infarction (AMI), conflicting findings have surfaced through large-scale observational studies and meta-analyses. We conducted this systematic review and meta-analysis of published observational studies to quantify the long-term therapeutic impact of beta-blocker across heterogeneous AMI populations.

Methods: We conducted comprehensive searches of the PubMed, Embase, Cochrane, and Web of Science databases for articles published from 2000 to 2025 that examine the link between beta-blocker therapy and clinical outcomes (last search update: March 1, 2025). We used the odds ratio (OR) with its 95% confidence interval (95% CI) to evaluate the effect of beta-blocker therapy on all-cause mortality, cardiac death, or major adverse cardiac events (MACE) in AMI patients. Our analysis stratified these effects by study type, ejection fraction (EF), sample size, follow-up duration, and patient characteristics including primary coronary revascularization, ST-segment elevation status, and comorbidities.

Results: This meta-analysis incorporated 34 observational studies covering 233,303 AMI patients. Our results showed beta-blockers reduced all-cause (OR = 0.73, 95% CI = 0.64-0.82) and cardiac mortality (OR = 0.79, 95% CI = 0.70-0.89) in post-AMI patients, with no significant effect on MACE. In these patients, post-PCI and STEMI patients, beta-blockers lowered all-cause mortality but not MACE risk. Subgroup analysis revealed that beta-blockers decreased all-cause death in post-AMI patients with diabetes and COPD, but not in those with hypertension and AF. Stratified by EF, beta-blockers were beneficial for all-cause death (OR = 0.75, 95% CI = 0.60-0.93), cardiac death (OR = 0.72, 95% CI = 0.56-0.92), and MACE (OR = 0.85, 95% CI = 0.76-0.96) in post-AMI patients with reduced EF and only decreased all-cause death in those with preserved EF.

Conclusions: Our meta-analysis suggests beta-blockers may offer long-term clinical benefits to AMI patients, particularly those with reduced EF. However, this is not conclusive for AMI patients with comorbidities or preserved EF.