Beta-Blocker Interruption or Continuation after Myocardial Infarction.

Background: The appropriate duration of treatment with beta-blocker drugs after a myocardial infarction is unknown. Data are needed on the safety and efficacy of the interruption of long-term beta-blocker treatment to reduce side effects and improve quality of life in patients with a history of uncomplicated myocardial infarction.
Methods: In a multicenter, open label, randomized, noninferiority trial conducted at 49 sites in France, we randomly assigned patients with a history of myocardial infarction, in a 1:1 ratio, to interruption or continuation of beta-blocker treatment. All the patients had a left ventricular ejection fraction of at least 40% while receiving long-term beta-blocker treatment and had no history of a cardiovascular event in the previous 6 months. The primary end point was a composite of death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for cardiovascular reasons at the longest follow-up (minimum, 1 year), according to an analysis of noninferiority (defined as a between-group difference of <3 percentage points for the upper boundary of the two-sided 95% confidence interval). The main secondary end point was the change in quality of life as measured by the European Quality of Life-5 Dimensions questionnaire.
Results: A total of 3698 patients underwent randomization: 1846 to the interruption group and 1852 to the continuation group. The median time between the last myocardial infarction and randomization was 2.9 years (interquartile range, 1.2 to 6.4), and the median follow-up was 3.0 years (interquartile range, 2.0 to 4.0). A primary-outcome event occurred in 432 of 1812 patients (23.8%) in the interruption group and in 384 of 1821 patients (21.1%) in the continuation group (risk difference, 2.8 percentage points; 95% confidence interval [CI], <0.1 to 5.5), for a hazard ratio of 1.16 (95% CI, 1.01 to 1.33; P = 0.44 for noninferiority). Beta-blocker interruption did not seem to improve the patients' quality of life.
Conclusions: In patients with a history of myocardial infarction, interruption of long-term beta-blocker treatment was not found to be noninferior to a strategy of beta-blocker continuation. (Funded by the French Ministry of Health and ACTION Study Group; ABYSS ClinicalTrials.gov number, NCT03498066; EudraCT number, 2017-003903-23.).
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