New study finds high rates of outpatient antibiotic exposure in children with medical complexity

A new study from Boston Children’s Hospital found that annual prescription rates increased nonlinearly as children’s underlying level of medical complexity increased. Frequent antibiotic use has associated risks, including an increased likelihood of antibiotic-related complications (e.g., C. difficile), as well as the development of antibiotic resistance.

Findings from the study were presented during the Pediatric Academic Societies (PAS) 2026 Meeting, held April 24–27 in Boston.

Overuse or misuse of antibiotics contributes to the growing global threat of antibiotic resistance. Children with medical complexity (CMC) are particularly vulnerable to frequent infections, yet knowledge of antibiotic use for this group is limited. This study found that children with three or more complex chronic conditions were more likely to fill prescriptions for broad-spectrum antibiotics with less favorable safety profiles.

Children with three or more complex chronic conditions have the highest annual prescription rates of any population group (adult or pediatric). CMC are an important target population for future antibiotic stewardship efforts.

“In this national analysis of outpatient antibiotic prescription fills among Medicaid-enrolled children, we found that antibiotic use was common, with more than a third of children filling at least one antibiotic prescription in 2023,” said Kathleen D. Snow, MD, Instructor of Pediatrics at Boston Children’s Hospital and lead author of the study.

“Children with multiple complex chronic conditions experienced markedly higher antibiotic prescription fill rates, greater annual antibiotic exposure, and more frequent use of broad-spectrum antibiotic drug classes compared with their healthy peers. These findings suggest that children with medical complexity may be a high-impact population for future antibiotic stewardship efforts.”

A retrospective cohort study of outpatient antibiotic prescription claims using the multistate MarketScan Medicaid Database was conducted.

Children ages 0-to-18 years continuously enrolled in Medicaid in 2023 were included and categorized into five mutually exclusive categories of underlying medical complexity: healthy (no chronic conditions), non-complex chronic condition (NC-C), and one, two, or three or more complex chronic conditions (CCC). Antibiotic fill rates per 1,000 persons were compared across groups using Poisson regression.

Of 2,357,642 children included in the analysis, 926,025 (39.3%) filled ≥1 antibiotic prescription [annual antibiotic prescription fill rate of 787 per 1,000 persons (95% CI: 786-788)]. Annual antibiotic prescription fill rates per 1,000 persons increased with higher levels of medical complexity (p<.001) from 514 (95% CI: 513, 516) in healthy children to 2,882 (95% CI: 2850, 2915) in children with three or more CCCs. Antibiotic exposure by drug class varied across medical complexity categories.

Penicillins, cephalosporins, and macrolides accounted for 93% of antibiotic prescriptions in healthy children, but only 64% of prescriptions in children with three or more CCCs.

Children with three or more CCCs had substantially more prescriptions for sulfonamides, quinolones, and aminoglycosides compared with their peers.