Association of β-blocker use at discharge and prognosis of oldest old with acute myocardial infarction: a prospective cohort study

Purpose It is uncertain whether beta-blockers are beneficial for long-term prognosis in older patients following acute myocardial infarction (AMI). Thus, this study sought to examine the effect of beta-blockers on long-term cardiovascular mortality (CVM) in the oldest old (>= 80 years) with AMI.Methods In this prospective, consecutive, non-randomized study, a total of 1156 patients with AMI admitted within 24 h after onset of symptoms were enrolled from January 2012 to February 2020. Univariate and multivariate Cox regression analyses were performed to examine the impact of beta-blocker use on prognosis. Furthermore, one-to-one propensity score matching (PSM) and inverse probability treatment weighting (IPTW) analyses were used to control for systemic differences between groups. The primary outcome was long-term CVM.Results Among the enrolled subjects, 972 (85.9%) were prescribed with beta-blockers at discharge. Over a mean follow-up of 26.3 months, 224 cardiovascular deaths were recorded. Both univariate [hazard ratio (HR), 1.41, 95% confidence interval (CI) 0.93-2.13] and multivariate (HR, 1.29, 95% CI 0.79-2.10) Cox regression analyses showed that beta-blocker use had no significant association with the long-term CVM, which was further demonstrated by PSM (HR, 1.31, 95% CI 0.75-2.28) and IPTW (HR, 1.41, 95% CI 0.73-2.69) analyses. Subgroup analyses according to sex, heart rate, hypertension, diabetes, revascularization, left ventricular ejection fraction, and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers use showed consistent results as well.Conclusion Our findings first suggested that the use of beta-blockers at discharge in oldest old with AMI was not useful for reducing post-discharge CVM, which need to be further verified by randomized controlled trials.