Macrolide antibiotics are increasingly recognized for their salutary anti-inflammatory effects in lung disease, potentially distinct from any antimicrobial effect.
Albert et al report that among 1,142 people with severe COPD (FEV1 ~40% predicted) who were randomized to take either azithromycin 250 mg or placebo daily for one year, those taking azithromycin had fewer exacerbations, as follows:
- 159 fewer exacerbations overall (741 vs. 900)
- 0.35 fewer exacerbations per patient-year of treatment (1.48 vs. 1.83), a number needed to treat of 3 to prevent an exacerbation (one patient for 3 years, or 3 patients for 1 year)
- Delay of 92 days in median time to first exacerbation (174 vs. 266 days)
Quality of life on the St. George's Respiratory Questionnaire improved by 2.8 points improved vs. 0.6 (with 4 being accepted as "clinically significant").
However, at least 32 more people in the azithromycin group experienced hearing loss (142 vs. 110), and in most, hearing did not return to baseline on repeat testing (nor did it in most of the placebo group, though). Authors attribute this to overestimation in both groups due to overly stringent criteria for hearing loss (but then, why the p-value of 0.04 for the difference?)
Albert RK et al. Azithromycin for Prevention of Exacerbations of COPD. N Engl J Med 2011;365:689-698.