Cole, Kristin

Abstract 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.