Clinical outcomes with beta-blocker use in patients with recent history of myocardial infarction

Background — It is uncertain whether beta-blockers (BBs) are beneficial in contemporary stable patients with prior myocardial infarction (MI). Therefore, we sought to examine the effectiveness of BB use in this population.

Methods — We conducted a cohort study with the use of administrative databases of patients ≥ 65 years of age, alive on April 1, 2012 (index date) with a hospital discharge diagnosis of MI within the previous 3 years. The primary outcome was time to death or hospitalization for MI or angina 1 year after the index date, with inverse probability of treatment weighting.

Results — We included 33,811 patients with prior MI, of whom 21,440 (63.4%) were dispensed a BB. The median age was 78 years, and 56% were male. There was no difference in the 1-year hazard of death/hospitalization for MI or angina (14.8% vs 14.7%, hazard ratio 1.00, 95% confidence interval 0.94-1.07; P = 0.90) in those receiving vs not receiving BB. Similarly, there was no difference in the individual end points in composite nor in 3-year outcomes. Subgroup analysis by age, sex, MI timing, MI type, heart failure, and atrial fibrillation found no benefit. Patients with a history of revascularisation treated with BBs had a lower rate of the composite outcome compared with those without such history ( P = 0.006 for interaction) at 1 year but not at 3 years.

Conclusions — In this large contemporary population-based observational study of older stable patients with prior MI, BBs were not associated with a reduction in major cardiovascular events or mortality in those with MI within the previous 3 years. This study supports the need to conduct contemporary clinical trials evaluating the use of BBs after MI.