Beta-blockers may lower 5-year risk for heart attack in patients with confirmed stable CAD
Key takeaways:
- Beta-blocker use was tied to lower 5-year risk for heart attack hospitalization vs. nonuse in obstructive coronary artery disease.
- The number needed to treat to prevent one major CV event at 5 years was 56.
Compared with nonuse, beta-blockers were linked to an 8% reduction in major CV events among patients with obstructive CAD referred for invasive testing, according to data published in the Journal of the American College of Cardiology.
Lucas C. Godoy, MD, research fellow at the Peter Munk Cardiac Centre and Heart & Stroke/Richard Lewar Centre at University of Toronto, and colleagues reported that this finding was primarily driven by a reduction in 5-year MI hospitalization among patients with stable CAD taking a beta-blocker compared with nonusers.
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“Despite the lack of good evidence, beta-blockers are currently used in > 70% of the patients with stable coronary artery disease, which perhaps is a reflection of the uncertainty of the existing data and persistence of treatment habits,” the researchers wrote. “In this contemporary population-based cohort study from Ontario, Canada, we studied the association between recently initiated beta-blocker therapy and long-term cardiovascular events in patients with angiographically confirmed stable coronary artery disease without heart failure or recent myocardial infarction.”
Using the CorHealth Ontario registry, Godoy and colleagues conducted the present population-based retrospective cohort analysis and included 28,039 patients with stable obstructive CAD (mean age, 73, years; 66% men) and recent MI or HF who underwent elective coronary angiography in Ontario from 2009 to 2019.
Beta-blocker use was defined as at least one beta-blocker prescription claim in the 90 days before or after coronary angiography.
The primary outcome was a composite of all-cause mortality and hospitalization for HF or MI.
Beta-blocker using in stable obstructive CAD
Overall, 45.3% of the cohort were newly prescribed a beta-blocker and the reminder were not on any beta-blocker.
The cumulative 5-year incidence of the primary outcome was 14.3% in the beta-blocker group and 16.1% in the group not on a beta-blocker, translating to an absolute risk reduction of approximately –1.8 percentage points (95% CI, 2.8 to 0.8; HR = 0.92; 95% CI, 0.86-0.98; P = .006).
This finding was primarily driven by reduced risk for MI hospitalization (HR = 0.87; 95% CI, 0.77-0.99; P = .031), as researchers observed no significant difference in 5-year all-cause death or HF hospitalization between patients prescribed beta-blockers and those who were not.
Godoy and colleagues estimated that the number of patients with stable CAD needed to treat with a beta-blocker to prevent one major CV event at 5 years was 56 (95% CI, 36-120).
These results were consistent across all subgroups, including those grouped by sex, age, diabetes, hypertension, coronary revascularization status, left ventricular ejection fraction range and patterns of myocardial ischemia and coronary anatomy, according to the study.
“Although the number needed to treat might seem small in magnitude, it is somewhat similar to many approved therapies for coronary artery disease,” the researchers wrote. “Examples are perindopril in EUROPA (number needed to treat of 50 over 4.2 years); ezetimibe in IMPROVE-IT (number needed to treat of 50 over 6 years); and empagliflozin in EMPA-REG OUTCOME (number needed to treat of 63 over 3.1 years).
“Given the low cost and known safety profile, even small risk reductions might be enough to justify a more generalized use of beta-blockers in patients with stable coronary artery disease, especially considering that most anti-anginal medications are not associated with cardioprotective benefits,” Godoy and colleagues wrote.
Rate of subsequent revascularization low
In a related editorial, Suzanne V. Arnold, MD, MHA, professor of medicine at the University of Missouri-Kansas City School of Medicine and clinical scholar at Saint Luke’s Mid America Heart Institute, drew attention to how few patients who underwent invasive testing subsequently underwent revascularization.
“For a cohort of patients who were referred for invasive diagnostic testing and found to have obstructive CAD, the percentage of patients who were then treated invasively was surprisingly low. ... [T]his practice pattern differs substantially from the United States and Europe, bringing into question the generalizability of these findings,” Arnold wrote.
Despite all participants undergoing coronary angiography, less than half underwent revascularization (17.1% on beta-blockers vs. 16.5% not on beta-blockers), according to the study.
“For medications that are exceedingly commonly used, knowing how beta-blockers affect outcomes in various situations is imperative,” Arnold wrote. “Observational studies help to raise the questions on treatment effects, but trials are needed for answers.”
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