Anticholinergics associated with higher mortality than long-acting inhaled beta-agonists in COPD

Long-acting inhaled beta-agonists were associated with lower mortality than anticholinergics in a new study of chronic obstructive pulmonary disease (COPD).

The retrospective cohort study used health administration data on more than 46,000 Canadian patients with COPD who were newly prescribed either a long-acting inhaled beta-agonist or an anticholinergic between 2003 and 2007. Patients were followed for up to 5.5 years, and results appeared in the May 3 Annals of Internal Medicine.

The overall mortality rate in studied patients was 38.2%. Mortality was 14% increased in patients initially prescribed an anticholinergic compared to those first taking a long-acting beta-agonist (39.9% vs. 36.5%, hazard ratio, 1.14, P<0.001). The anticholinergic group also had higher rates of disease-related hospitalizations and emergency department visits (70.3% vs. 67.8% for both outcomes combined, P<0.001). The rates of mortality and hospital visits were adjusted for a number of factors, including sex, comorbidity and whether patients had undergone spirometry.

This study is thought to be the first to evaluate mortality according to the initial drug class prescribed, the study authors said. Prior research has found them to be equally effective in preventing exacerbations and hospitalizations. Although this study is limited by its observational nature and the associated risk of confounding, it also has certain advantages over randomized controlled trials, the authors said. Randomized trials are often smaller, may exclude sicker and older patients (of which this study had many), and may use patients who are not new to the studied medications. As an observational study, this research was not able to establish the reason for the difference in mortality, but the authors speculated that long-acting anticholinergics may actually increase mortality risk, rather than just reducing it less than the long-acting beta-agonists do.

The results of this study suggest that long-acting beta-agonists may be a better initial therapy for patients with moderate to severe COPD, the authors concluded. They called for randomized controlled trials and research in younger patients to confirm these findings.