BOSTON, April 24, 2026 – A new study from Boston Children's Hospital found that annual prescription rates increased non-linearly as children’s underlying level of medical complexity increased. Frequent antibiotic use has associated risks, including increased likelihood of antibiotic-related complications (e.g., C. difficile) as well as the development of antibiotic resistance. Findings from the study will be presented during the Pediatric Academic Societies (PAS) 2026 Meeting , taking place 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 multi-state 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 (Figure 1). 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.
Additional information is included in the below research abstract. The PAS Meeting connects thousands of leading pediatric researchers, clinicians and educators worldwide. View the full schedule in the PAS 2026 program guide . For more information about the PAS Meeting, please visit www.pas-meeting.org .
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Abstract: Medical Complexity and High Rates of Outpatient Antibiotic Exposure
Presenting Author
Kathleen D. Snow, MD, MPH, Instructor of Pediatrics, Boston Children's Hospital
Organization
Boston Children's Hospital
Topic
Children with Chronic Conditions
Background
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.
Objective
To measure annual outpatient antibiotic prescription fill rates in children by degree of underlying medical complexity.
Design/Methods
We conducted a retrospective cohort study of outpatient antibiotic prescription claims using the multi-state MarketScan Medicaid Database. Children ages 0-to-18 years continuously enrolled in Medicaid in 2023 were included and categorized into 5 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.
Results
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 3+ CCCs. Antibiotic exposure by drug class varied across medical complexity categories (Figure 1). Penicillins, cephalosporins, and macrolides accounted for 93% of antibiotic prescriptions in healthy children, but only 64% of prescriptions in children with 3+ CCCs. Children with 3+ CCCs had substantially more prescriptions for sulfonamides, quinolones, and aminoglycosides compared with their peers.
Conclusion(s)
Annual prescription rates increased non-linearly as children’s underlying level of medical complexity increased. Children with 3+ CCCs were more likely to fill prescriptions for broad-spectrum antibiotics with less favorable safety profiles. Children with 3+ CCCs have the highest annual prescription rates of any population group (adult or pediatric). Frequent antibiotic use has associated risks, including increased likelihood of antibiotic-related complications (e.g., C. difficile) as well as the development of antibiotic resistance. CMC are an important target population for future antibiotic stewardship efforts.
Co-Authors
Matt Hall, PhD, Principal Biostatistician, Children's Hospital Association
Jay Berry, MD, MPH, Chief, Complex Care, Boston Children's Hospital
Jonathan Mansbach, MD, MPH, Chief, Hospital Medicine, Boston Children's Hospital
Tables and Images
Antibiotic prescription fill rates by drug class and medical complexity in 2023
Bar charts depict annual antibiotic prescription fill rates per 1,000 persons for children ages 0-18 years by category of medical complexity: healthy children, non-complex chronic conditions (NC-C), and complex chronic condition (CCC) count (1, 2, or 3+). Error bars represent 95% confidence intervals. Note: Y-axis scales are unique to each drug class graph.