Atenolol or Bisoprolol after Myocardial Infarction without Recorded Heart Failure

BACKGROUND: Beta-blockers are a cornerstone of therapy following myocardial infarction. The effect of different β-blockers on the outcomes of patients without heart failure after myocardial infarction is not well-studied. METHODS: This observational cohort study used administrative data from French National Health Data System. Eligible patients were 18 years of age or older, hospitalized in the Paris area between January 1, 2008, and December 31, 2018, with a new myocardial infarction, and were dispensed either atenolol or bisoprolol within 2 days of hospital discharge. Patients prescribed β-blockers or loop diuretics or with a recorded diagnosis of heart failure (based on International Classification of Diseases, 10th Revision codes) during the 2 years preceding hospital discharge were excluded. Outcomes were followed for up to 2 years following hospital discharge and included major adverse cardiovascular events (cardiac arrest, all-cause mortality, reinfarction, stroke, or hospitalization for heart failure) (primary outcome) and all-cause mortality (secondary outcome). Targeted maximum likelihood estimation was used to estimate the average treatment effects (ATEs) comparing patients initiated on atenolol versus bisoprolol. RESULTS: Among 11,558 patients, 1523 (13.2%) initiated atenolol and 10,035 (86.8%) initiated bisoprolol within 2 days of discharge. Comparing the atenolol group to the bisoprolol group, the ATE was 2.9 percentage points (95% confidence interval [CI], 1.1-4.7) for major adverse cardiovascular events and 0.6 percentage points (95% CI, -0.2 to 1.3) for all-cause mortality. The weighted proportions of patients experiencing major adverse cardiovascular events were 10.8% and 14.1% in the atenolol and bisoprolol groups, respectively. The weighted proportions of patients experiencing all-cause mortality were 1.4% and 2.2% in the atenolol and bisoprolol groups, respectively. CONCLUSIONS: Among patients without recorded characteristics in an administrative database suggesting the presence of heart failure, initiation of atenolol after myocardial infarction was associated with a lower risk of major adverse cardiovascular events, but not all-cause mortality, at 2 years compared with bisoprolol. (Funded by PRAIRIE and others.).