Meta-analysis of randomized controlled trials on the comparative efficacy and safety of azithromycin against other antibiotics for upper respiratory tract infections

We carried out a meta-analysis of randomized controlled trials of azithromycin compared with other antibiotics in the treatment of lower respiratory tract infections, including acute bronchitis (five comparisons including 1372 patients), acute exacerbations of chronic bronchitis (13 comparisons including 1342 patients) and community-acquired pneumonia (18 comparisons with 1664 patients). For the first two indications, azithromycin did not offer any statistically significant reduction in clinical failures [random effects odds ratios 0.84, 95% confidence interval (CI) 0.54-1.31 and 0.64, 95% CI 0.31-1.32, respectively] and absolute risk differences were small. For community-acquired pneumonia, azithromycin significantly reduced clinical failures by about one-third (random effects odds ratio 0.63, 95% CI 0.41-0.95). The absolute incremental benefit was approximately one clinical failure prevented per 50 treated patients with community-acquired pneumonia. There was no significant heterogeneity for different comparators and for bacterial versus atypical pneumonias. Azithromycin was discontinued because of adverse events in only 23 of 3487 patients (0.7%). Although results should be interpreted cautiously as most trials were open-label and susceptible to bias, the meta-analysis indicates that, compared with antibiotics with traditional pharmacokinetics that require more prolonged courses, azithromycin offers no significant advantage for bronchitis, but may be more effective in community-acquired pneumonia.