Among patients with moderate or severe chronic obstructive pulmonary disease (COPD) who do not have an established indication for beta-blocker use, the time to first COPD exacerbation is similar whether they are receiving metoprolol or placebo, according to results from a prospective, randomized trial published in the New England Journal of Medicine.

Beta-blockers reduce mortality in patients who have had a myocardial infarction and in those with heart failure, but are often not used in patients with COPD because of concerns regarding possible adverse effects on lung function.

However, observational studies suggest that beta-blockers may reduce the risk for exacerbations and death in patients with moderate or severe COPD, although these findings have not been confirmed. Therefore researchers investigated the effect of metoprolol compared with placebo on the risk for COPD exacerbations among high-risk patients.