Abstract Body (Do not enter title and authors here): Background: The long-term benefit of beta-blockers (BBs) in post-myocardial infarction (MI) patients without heart failure (HF) or arrhythmias remains uncertain. This study aimed to assess the clinical significance of BB therapy initiated within one year of MI on major cardiovascular outcomes in a real-world cohort.
Methods: We conducted a retrospective cohort study using the TriNetX U.S. Collaborative Network. Adults with a history of MI were included if they had no documented HF or arrhythmias pre-MI through 1-year post-MI. Patients were categorized based on whether they were prescribed BBs during the 1-year post-MI window. Propensity score matching (1:1) was performed based on demographics and cardiovascular risk factors. The composite outcome included all-cause mortality, stroke, cardiogenic shock, cardiac arrest, ventricular tachycardia, HF, and new arrhythmias occurring between 1-15 years post-MI. Cox regression and Kaplan-Meier survival analysis were used to assess associations between BB therapy and clinical endpoints.
Results: After matching, 113,727 patients were included per BB vs no-BB groups (mean age: 68.5 vs. 67.9 years; male: 57.2% vs. 57.7%; hypertension: 29.0% vs. 28.8%; diabetes: 13.7% vs. 13.8%). At a follow-up of 15 years, there was a statistically significant difference in the composite outcome between the BB and no-BB groups (17.1% vs 18.8%, p<0.01) with a hazard ratio of 0.91 (95% CI 0.89–0.92). Additionally, KM survival analysis showed improved 15-year survival with BB therapy (63.8% vs 64.7%, Log-Rank p=0.02).
Conclusion: In patients without heart failure or arrhythmias during the first year following an MI, beta-blocker therapy initiated during that year conferred a statistically significant reduction in cardiovascular outcomes and improved survival at 15-year follow-up.