Azithromycin for Critically Ill Children With Bronchiolitis: A U.S. Pediatric Health Information Systems Registry Study, 2013-2022.

Objectives: To estimate prescribing rates for azithromycin as immunomodulation among critically ill children hospitalized for acute bronchiolitis and identify institutional and chronological prescribing variation.

Design: Multicenter, observational, retrospective cohort study using the Pediatric Health Information Systems registry from 2013 to 2022.

Setting: Forty-seven PICUs in the United States.

Patients: Critically ill children 0-3 years old hospitalized for acute viral bronchiolitis excluding those prescribed azithromycin with alternative indication (i.e., concurrent Bordetella pertussis infection, urethritis, atypical pneumonia, acute upper respiratory infections, and asthma-related diagnoses).

Interventions: Azithromycin prescription during hospitalization.

Measurements and main results: A total of 82,677 children met study criteria of which 3,161 (3.8%) were prescribed azithromycin. Mean (± sd ) center-specific azithromycin prescribing rates exhibited a multilinear decreasing trend (joinpoint breakpoint noted in 2017) going from 4.0% ± 4.6% in 2013 to 2.2% ± 0.8% in 2022 (-0.7%/yr). The median institutional azithromycin prescribing rate was 2.8% (interquartile range [IQR], 1.8-3.9%; total range, 1.2-24.3%). Compared with those not prescribed azithromycin, receipt of azithromycin was associated with the following: older age (median, 10 mo [IQR, 3.2-20.3 mo] vs. 7.8 mo [IQR, 2.9-15.2 mo]; p < 0.001); receiving corticosteroids (57.1% vs. 38.1%; p < 0.001) or continuous albuterol (35.9% vs. 22.4%; p < 0.001); use of noninvasive respiratory support (13.4% vs. 9.7%; p < 0.001) or invasive ventilation (35.9% vs. 22.4%; p < 0.001); and extracorporeal life support (0.5% vs. 0.1%; p < 0.001).

Conclusions: In this 2013-2022, U.S. multicenter registry-based cohort study, the azithromycin prescribing rate for critically ill children with bronchiolitis was 3.8%. Exposure varied by institution, patient age, and revealed a decreasing trend over the last decade.