Azithromycin treatment in children hospitalized with asthma: a retrospective cohort study

Objective: Azithromycin has anti-inflammatory properties in the lungs and decreases the duration of asthma-like episodes in children. We sought to evaluate length of stay (LOS) and readmission rates of children receiving azithromycin therapy during hospitalization for acute asthma exacerbations. Methods: This was a retrospective cohort study at an urban, quaternary-care children's hospital including patients under 18 years old hospitalized for asthma, without concurrent infection, from 2002 to 2011. The primary predictor was azithromycin therapy administered within 48 hours of admission. The primary outcome was LOS and the secondary outcomes were 7, 30, and 90-day hospital readmission rates for asthma. Results: Azithromycin therapy was administered to 174 (3%) of 5335 unique patients admitted for asthma, without concurrent infection, over the 10-year period. The overall median LOS was 2.3 days [Interquartile range, 1.8-3.1] and 9% (480) were readmitted for asthma within 90 days of discharge. Azithromycin therapy was associated with a 20% (11 hour) longer LOS (adjusted beta coefficient for log-transformed LOS, 0.18; 95% Confidence Interval (CI): 0.11-0.26), less than the 29% (16 hour) difference determined a priori as clinically relevant. Azithromycin therapy was not associated with 90-day readmission for asthma (adjusted odds ratio, 0.89; 95% CI: 0.46-1.72]. The limited number of 7 and 30-day readmissions in the azithromycin treated group precluded adjusted analysis. Conclusions: Azithromycin therapy was not associated with a clinically relevant difference in hospital LOS or with readmission rates for children hospitalized with asthma. Prospective trials are needed to determine the clinical effects of azithromycin therapy in children with asthma.