Azithromycin for Bronchial Asthma in Adults: An Effectiveness Trial

Background: Macrolides have antimicrobial and anti-inflammatory properties that may be useful in the treatment of chronic asthma.

Methods: We performed a randomized, placebo-controlled, double-blinded effectiveness trial of 12 weekly doses of adjunctive azithromycin, with follow-up to 1 year after randomization, in adults with persistent asthma. Measurements included overall asthma symptoms, asthma quality of life (AQL), and asthma control. Eligible subjects who declined to participate in randomization were offered enrollment into a parallel open-label (OL) azithromycin treatment arm.

Results: Of 304 adult asthma patients screened, 97 (32%) were enrolled: 38 were randomized to azithromycin, 37 were randomized to placebo, and 22 opted in as OL subjects. OL subjects had higher rates of severe persistent asthma compared with randomized subjects (32% vs 8%, respectively; P = .012). At 1 year, compared with the placebo arm, subjects randomized to azithromycin were more likely to have an AQL score ≥1 unit increase compared with baseline, but this difference was not statistically significant (36% vs 21% for placebo; P = .335). Compared with placebo, OL subjects had significant improvements in overall asthma symptoms from baseline (P = .0196), AQL (P = .0006), and asthma control (P = .0148).

Conclusions: Adults with asthma who were randomized to azithromycin did not show statistically significant improvement in asthma outcomes, although the study was underpowered to detect clinical improvement in 15% (number needed to treat = 7). Adults with severe persistent asthma who elected OL treatment documented clinical improvements in asthma symptoms, AQL, and asthma control that persisted after completion of OL azithromycin (number needed to treat = 2).