The effect of discontinuing beta-blockers after different treatment durations following acute myocardial infarction in optimally treated, stable patients without heart failure: a Danish, nationwide cohort study

AIMS: We studied the effect of discontinuing beta-blockers following myocardial infarction in comparison to continuous beta-blocker use in optimally treated, stable patients without heart failure. METHODS AND RESULTS: Using nationwide registers, we identified first-time myocardial infarction patients treated with beta-blockers following percutaneous coronary intervention or coronary angiography. The analysis was based on landmarks selected as 1, 2, 3, 4, and 5 years after the first redeemed beta-blocker prescription date. The outcomes included all-cause death, cardiovascular death, recurrent myocardial infarction, and a composite outcome of cardiovascular events and procedures. We used logistic regression and reported standardized absolute 5-year risks and risk differences at each landmark year. Among 21 220 first-time myocardial infarction patients, beta-blocker discontinuation was not associated with an increased risk of all-cause death, cardiovascular death, or recurrent myocardial infarction compared with patients continuing beta-blockers (landmark year 5; absolute risk difference [95% confidence interval]), correspondingly; -4.19% [-8.95%; 0.57%], -1.18% [-4.11%; 1.75%], and -0.37% [-4.56%; 3.82%]). Further, beta-blocker discontinuation within 2 years after myocardial infarction was associated with an increased risk of the composite outcome (landmark year 2; absolute risk [95% confidence interval] 19.87% [17.29%; 22.46%]) compared with continued beta-blocker use (landmark year 2; absolute risk [95% confidence interval] 17.10% [16.34%; 17.87%]), which yielded an absolute risk difference [95% confidence interval] at -2.8% [-5.4%; -0.1%], however, there was no risk difference associated with discontinuation hereafter. CONCLUSION: Discontinuation of beta-blockers 1 year or later after a myocardial infarction without heart failure was not associated with increased serious adverse events.