Hospital variation in admissions to neonatal intensive care units by diagnosis severity and category

OBJECTIVE: To examine interhospital variation in admissions to neonatal intensive care units (NICU) and reasons for the variation. STUDY DESIGN: 2010–2012 linked birth certificate and hospital discharge data from 35 hospitals in California on live births at 35–42 weeks gestation and ≥1500 g birth weight were used. Hospital variation in NICU admission rates was assessed by coefficient of variation. Patient/hospital characteristics associated with NICU admissions were identified by multivariable regression. RESULTS: Among 276,489 newborns, 6.3% were admitted to NICU with 34.5% of them having mild diagnoses. There was high interhospital variation in overall risk-adjusted rate of NICU admission (coefficient of variation = 26.2) and NICU admission rates for mild diagnoses (coefficient of variation: 46.4–74.0), but lower variation for moderate/severe diagnoses (coefficient of variation: 8.8–14.1). Births at hospitals with more NICU beds had a higher likelihood of NICU admission. CONCLUSION: Interhospital variation in NICU admissions is mostly driven by admissions for mild diagnoses, suggesting potential overuse.