Clinical Events After Discontinuation of -Blockers in Patients Without Heart Failure Optimally Treated After Acute Myocardial Infarction A Cohort Study on the French Healthcare Databases

Background: beta-blockers have been among the first medications shown to improve outcomes after acute myocardial infarction (AMI). With the advent of reperfusion therapy and other secondary-prevention medications, their role has become uncertain, and large-scale experience after AMI in the contemporary era is lacking. In particular, the effect of stopping -blockers in patients initially treated after AMI is unknown. Methods and Results: Using the French healthcare databases, 73450 patients (<80 years of age), admitted for AMI in 2007 to 2012, without acute coronary syndrome (ACS) in the previous 2 years and no evidence of heart failure, having received optimal treatment with myocardial revascularization and all recommended medications in the 4 months after index admission, and not having discontinued beta-blockers before 1 year, were followed for 3.8 years on average. beta-Blocker discontinuation was defined as 4 consecutive months without exposure. If beta-blocker treatment was resumed later on, follow-up was stopped. Both the risk of the composite outcome of death or admission for ACS and the risk of all-cause mortality were assessed in relation with beta-blocker discontinuation during follow-up. Adjusted hazard ratios were estimated using marginal structural models accounting for time-varying confounders affected by previous exposure. A similar analysis was performed with statins. Of 204592 patient-years, 12002 (5.9%) corresponded to discontinued beta-blocker treatment. For beta-blocker discontinuation, the adjusted hazard ratio for death or ACS was 1.17 (95% confidence interval, 1.01-1.35); for all-cause death, the adjusted hazard ratio was 1.13 (95% confidence interval, 0.94-1.36). In contrast, for statin discontinuation, the adjusted hazard ratios for death or ACS and for all-cause death were 2.31 (95% confidence interval, 2.01-2.65) and 2.57 (95% confidence interval, 2.19-3.02), respectively. Conclusions: In routine care of patients without heart failure, revascularized and optimally treated after AMI, discontinuation of beta-blockers beyond 1 year after AMI was associated with an increased risk of death or readmission for ACS, while statistical significance was not reached for the association with all-cause mortality. A contemporary randomized clinical trial is needed to precise the role of -blockers in the long-term treatment after AMI.