Background: Beta-blockers are underutilized in patients with both COPD and established cardiovascular indications for beta-blocker therapy, despite evidence suggesting overall benefit. Prior observational studies have associated beta-blockers with improved outcomes in COPD in the absence of cardiovascular indications; however, this has not been previously evaluated in a randomized trial.
Dr. John Gerstenberger
Study design: Placebo-controlled, double-blind, prospective, randomized trial.
Setting: A total of 26 centers in the United States.
Synopsis: The BLOCK COPD trial randomized more than 500 patients with moderate to severe COPD and no established indication for beta-blocker therapy to extended-release metoprolol or placebo. There was no significant difference in the primary endpoint of time until first exacerbation. While there was no difference in the overall risk of exacerbations of COPD, the trial was terminated early because of increased risk of severe or very severe exacerbations of COPD in the metoprolol group (hazard ratio, 1.91; 95% confidence interval, 1.20-2.83). These were defined as exacerbations requiring hospitalization and mechanical ventilation, respectively.
Importantly, this trial excluded patients with established indications for beta-blocker therapy, and study findings should not be applied to this population.
Bottom line: Metoprolol is not associated with increased risk of COPD exacerbations, but is associated with increased severity of COPD exacerbations in patients with moderate to severe COPD who have no established indications for beta-blockers.
Citation: Dransfield MT et al. Metoprolol for the prevention of acute exacerbations of COPD. N Engl J Med. 2019 Oct 20. doi: 10.1056/NEJMoa1908142.
Dr. Gerstenberger is a hospitalist and clinical assistant professor of medicine at the University of Utah, Salt Lake City.