Long-Term β-blocker therapy and clinical outcomes after acute myocardial infarction in patients without heart failure: Nationwide cohort study

Aims: To investigate the association between long-Term β-blocker therapy and clinical outcomes in patients without heart failure (HF) after acute myocardial infarction (AMI). Method and results: Between 2010 and 2015, a total of 28 970 patients who underwent coronary revascularization for AMI with β-blocker prescription at hospital discharge and were event-free from death, recurrent myocardial infarction (MI), or HF for 1 year were enrolled from Korean nationwide medical insurance data. The primary outcome was all-cause death. The secondary outcomes were recurrent MI, hospitalization for new HF, and a composite of all-cause death, recurrent MI, or hospitalization for new HF. Outcomes were compared between β-blocker therapy for ≥1 year (N = 22 707) and β-blocker therapy for <1 year (N = 6263) using landmark analysis at 1 year after index MI. Compared with patients receiving β-blocker therapy for <1 year, those receiving β-blocker therapy for ≥1 year had significantly lower risks of all-cause death [adjusted hazard ratio (HR) 0.81; 95% confidence interval (CI) 0.72-0.91] and composite of all-cause death, recurrent MI, or hospitalization for new HF (adjusted HR 0.82; 95% CI 0.75-0.89), but not the risks of recurrent MI or hospitalization for new HF. The lower risk of all-cause death associated with persistent β-blocker therapy was observed beyond 2 years (adjusted HR 0.86; 95% CI 0.75-0.99) but not beyond 3 years (adjusted HR 0.87; 95% CI 0.73-1.03) after MI. Conclusion: In this nationwide cohort, β-blocker therapy for ≥1 year after MI was associated with reduced all-cause death among patients with AMI without HF.