Association of beta-blocker therapy with cardiovascular outcomes in patients with stable ischemic heart disease

Background — Previous studies have failed to show a cardioprotective benefit of beta-blockers in patients with stable coronary artery disease (CAD).

Objectives —This study sought to determine the association between beta-blockers and cardiovascular events in patients with stable CAD using a new user design.

Methods — All patients aged >66 years undergoing elective coronary angiography in Ontario, Canada, from 2009 to 2019 with diagnosed obstructive CAD were included. Exclusion criteria included heart failure or a recent myocardial infarction, as well as having a beta-blocker prescription claim in the previous year. Beta-blocker use was defined as having at least 1 beta-blocker prescription claim in the 90 days preceding or after the index coronary angiography. The main outcome was a composite of all-cause mortality and hospitalization for heart failure or myocardial infarction. Inverse probability of treatment weighting using the propensity score was used to account for confounding.

Results — This study included 28,039 patients (mean age: 73.0 ± 5.6 years; 66.2% male), and 12,695 of those (45.3%) were newly prescribed beta-blockers. The 5-year risks of the primary outcome were 14.3% in the beta-blocker group and 16.1% in the no beta-blocker group (absolute risk reduction: −1.8%; 95% CI: −2.8 to −0.8; HR: 0.92; 95% CI: 0.86-0.98; P = 0.006). This result was driven by reductions in myocardial infarction hospitalization (cause-specific HR: 0.87; 95% CI: 0.77-0.99; P = 0.031), whereas no differences were observed in all-cause death or heart failure hospitalization.

Conclusions — In patients with angiographically documented stable CAD without heart failure or a recent myocardial infarction, beta-blockers were associated with a small but significant reduction in cardiovascular events at 5 years.