Background: Necrotizing enterocolitis (NEC) preferentially affects very low birth weight (VLBW) infants at risk for other comorbidities, including intraventricular hemorrhage (IVH). While NEC and IVH are individually associated with increased mortality, their combined incidence and effects are poorly defined. Methods: Data were prospectively collected on VLBW infants born 2014-2018 enrolled in a national neonatal database. NEC was defined as one radiographic and one clinical characteristic, or confirmation at laparotomy or autopsy. IVH was categorized as absent, mild (grade 1-2) or severe (grade 3-4). Adjusted risk ratios were calculated controlling for birth weight, small for gestational age, antenatal steroids, inborn status and clustering between hospitals. Results: 187,187 VLBW infants were evaluated. 141,015(75.3%) had no IVH, 31,793(17.0%) had mild IVH and 14,379(7.7%) had severe IVH. Increasing severity of IVH was associated with lower birth weight, more comorbidities and increasing incidence of NEC. On univariate analysis, mortality increased with severity of IVH (no IVH 3.8%, mild 7.4%, severe 31.6%) and with severity of NEC (no NEC 5.2%, medical NEC 19.2%, surgical NEC 32.1%). On adjusted analysis, the higher mortality seen with increased severity of NEC was mitigated by increasing severity of IVH (Figure). Infants without IVH had a notable increase in mortality with increasing severity of NEC (2.7% to 15.5% to 30.8% for no NEC, medical NEC and surgical NEC, respectively), but this increase was less marked in mild IVH and absent in severe IVH (30.2%, 39.3% and 39.3%). Conclusions: Infants with IVH are more likely to have NEC. In this multicenter, prospectively collected cohort, increasing severity of IVH and NEC, individually, is associated with increasing mortality, but the increased mortality is not substantially compounded when the two diseases occur together. Given the frequent coexistence of these two conditions, these data are important to help guide the multidisciplinary management of these complex patients.

Figure

Adjusted risk (95% CI) of mortality prior to hospital discharge in infants with IVH and NEC. Risk ratios adjusted for birth weight, small for gestational age, antenatal steroid administration and inborn status. No NEC is the reference in each IVH category.

Figure

Adjusted risk (95% CI) of mortality prior to hospital discharge in infants with IVH and NEC. Risk ratios adjusted for birth weight, small for gestational age, antenatal steroid administration and inborn status. No NEC is the reference in each IVH category.

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