Serial inflammatory marker monitoring for children hospitalized with common bacterial infections.

BACKGROUND: C-reactive protein (CRP) is a frequently used inflammatory marker for common pediatric infections such as community-acquired pneumonia (CAP), skin and soft tissue infection (SSTI), and urinary tract infection (UTI). Although serial inflammatory marker (sIM) monitoring may support clinical decision-making and antibiotic stewardship, guidelines for use in these conditions remain limited. OBJECTIVES: This study aimed to describe hospital-level variation in sIM monitoring for children hospitalized with CAP, SSTI, and UTI, and evaluate associations with clinical outcomes and resource utilization. METHODS: This multicenter study using the Pediatric Health Information System database included children aged 3 months-18 years hospitalized 7/2022-6/2025 with CAP, SSTI, or UTI. sIM monitoring was defined as ≥2 CRP tests on separate hospital days. For each condition, hospitals were categorized as low, moderate, or high utilizers of sIM monitoring and variation across hospitals was assessed. Generalized estimating equation models evaluated associations between hospital sIM utilization and intravenous antibiotic duration, length of stay, cost, and 7-day Emergency Department revisits/readmissions. RESULTS: Among 50,747 encounters, sIM monitoring occurred in 8.7% of CAP, 18.4% of SSTI, and 22.9% of UTI hospitalizations, with substantial interhospital variation. Higher sIM monitoring for one condition correlated with higher monitoring for other conditions. High-utilizing hospitals had longer intravenous antibiotic duration for UTI (odds ratio [OR] 1.16, 95% confidence interval [CI] 1.05-1.29). For CAP and SSTI, sIM utilization was not associated with any outcome. CONCLUSIONS: sIM monitoring is highly variable across hospitals without an association with decreased intravenous antibiotic duration. Future studies should assess testing strategies to optimize child health outcomes and antibiotic stewardship.