Hospital-level Antibiotic Use and Complexity of Care Among Neonates

Background: Despite increasing neonatal antibiotic stewardship efforts, understanding of interhospital variation in neonatal antibiotic use is limited. Methods: A retrospective cohort study was conducted among primarily academically affiliated hospitals participating in the Vizient Clinical Database/Resource Manager. Neonatal discharges were identified by admission age <1 month, excluding nonviable neonates and normal newborns. Hospitals with ≥100 neonatal discharges and complete data for January-December 2016 were included. Antibiotic use was measured in days of therapy per 1000 patient-days (DOT/1000 pd). A composite measure of neonatal care complexity (NCC; low, medium, high) was based on the volume of very low-birth-weight neonates and neonates undergoing surgical procedures, cardiac surgery, or extracorporeal membranous oxygenation. Results: The 118 included hospitals represented 184 716 neonatal discharges; 22 hospitals with low NCC, 56 with medium NCC, and 40 with high NCC. Mean antibiotic DOT/1000 pd was 363 (standard deviation [SD], 94) in high NCC hospitals, 243 (SD, 88) in medium NCC hospitals, and 184 (SD, 122) in low NCC hospitals. Increasing NCC was associated with higher antibiotic use, with an incidence rate ratio (IRR) of 1.95 (95% confidence interval [CI], 1.55 to 2.47) for high vs low NCC and IRR 1.31 (95% CI, 1.05 to 1.64) for medium vs low NCC. Increasing case mix index was associated with higher antibiotic use (IRR 1.86 per unit increase; 95% CI, 1.50 to 2.31). Conclusions: Aggregate antibiotic use among hospitalized neonates varies based on care complexity. Substantial variation despite stratification by complexity suggests incomplete risk adjustment and/or avoidable variation in care.