Supplementary Material for: Type of Re-Hospitalization and Association with Neonatal Morbidities in Infants of Very Low Birth Weight

Background: Preterm infants are at high risk for long-term morbidities and an increased rate of re-hospitalization. Objective: The aim of this study was to evaluate the type of re-hospitalization of very low birth weight (VLBW) infants, from infancy through adolescence, and to assess the association of neonatal morbidities with specific types of re-hospitalization. Study Design: The study cohort comprised 6,385 VLBW infants who were registered with the Maccabi Healthcare Services (MHS) from their birth hospitalization. Data were collected for up to 18 years (median 10.7 years) following neonatal intensive care unit discharge. Hospitalization types were determined from the MHS coding. Neonatal morbidities included necrotizing enterocolitis (NEC), grades 3–4 intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), bronchopulmonary dysplasia (BPD), and retinopathy of prematurity (ROP). Adjusted hazard ratios (aHR) and 95% confidence intervals (CI) were calculated using the Cox proportional hazards model. Results: Overall, 3,956 infants were re-hospitalized at least once and a total of 11,595 hospitalization types were identified. NEC, IVH, PVL, and BPD were associated with significantly higher aHRs for general pediatric (aHR 1.28–1.55), general surgical (aHR 1.18–1.46), and pediatric intensive care unit (aHR 1.57–2.04) hospitalizations. IVH and PVL were associated with significantly higher aHRs for orthopedic (aHR 2.12 and 4.88, respectively) and ophthalmology (1.76 and 4.02, respectively) hospitalizations. IVH was associated with a 14.2-fold higher aHR for neurosurgical admissions, and ROP with a 1.62-fold higher aHR for ophthalmology hospitalizations. Conclusion: Among VLBW infants, specific patterns of re-hospitalization types associated with major neonatal morbidities were identified as particularly high risks for orthopedic and ophthalmology hospitalizations in infants with IVH and PVL, and for intensive care admissions in infants with NEC and BPD.