Comparative Effectiveness of Azithromycin Versus Doxycycline in Hospitalized Patients With Community-Acquired Pneumonia Treated With Beta-Lactams: A Multicenter Matched Cohort Study

BACKGROUND: Doxycycline is a frequently used alternative treatment for community-acquired pneumonia (CAP) in hospitalized patients; however, the evidence base is limited. We aimed to compare outcomes in CAP patients treated with doxycycline or azithromycin in combination with beta-lactams. METHODS: We evaluated patients with CAP admitted to Mayo Clinic hospitals from May 2018 to September 2022 and treated with either azithromycin or doxycycline in combination with a beta-lactam. Patients who received both antibiotics or were on either antibiotic as chronic therapy prior to admission were excluded. The primary outcome was mortality. Patients were 1-to-1 matched according to the presence of congestive heart failure, coronary artery disease, chronic obstructive pulmonary disease, human immunodeficiency virus infection, recent immunosuppressant use, and pneumonia severity index class. RESULTS: Among 8492 patients (5810 for azithromycin, 2682 for doxycycline), 2671 doxycycline-treated patients were matched with azithromycin-treated patients. In-hospital mortality was significantly lower in the azithromycin group than in the doxycycline group (odds ratio, 0.71; 95% confidence interval [CI], .56-.9), as was 90-day mortality (hazard ratio, 0.83; 95% CI, .73-.95). Patients on azithromycin also had significantly more hospital-free days (HFDs) than those on doxycycline (estimate, 1.37; 95% CI, .99-1.74). CONCLUSIONS: Among hospitalized patients with CAP, azithromycin was associated with lower mortality and more HFDs compared with doxycycline in combination with beta-lactams. Randomized, controlled trials are needed to assess the effectiveness of each regimen and to compare their potential side effects.