30 Risk Factors for Stage III Necrotizing Enterocolitis in Very Low Birth Weight Neonates – A retrospective case-control study

Primary Subject area Neonatal-Perinatal Medicine Background Stage III necrotizing enterocolitis (NEC-III) is a serious intestinal inflammatory disease in neonates, with high case fatality rate and significant morbidities including need for surgical intervention. Research focusing on risk factors for the development of NEC-III are lacking. Objectives To determine the risk factors for NEC-III and its outcomes among neonates born under 33 weeks gestational age (GA). Design/Methods This was a single-centre retrospective case-control study of preterm neonates born under 33 weeks GA who were admitted to Stollery Children’s Hospital neonatal intensive care unit (NICU), Edmonton, Alberta, between January 2015 and December 2018. NEC-III cases were compared with Stage II NEC (NEC-II) and matched with 2-4 non-NEC controls by GA ± 1 week and date of birth within 3 months. Univariate and multivariate analysis compared the risk factors for NEC-III, adjusting for GA, birth weight, and sex. Results Out of 1360 babies born <33weeks, 71(5.2%) had NEC-II and above during the study period (Figure 1). NEC-III constituted 46% of the total number of NEC cases. Average age of onset of NEC-III was 13.7 days versus 23.9 days for NEC-II (p=0.01). Neonates with NEC-III were of lower GA (25.4weeks) compared to NEC-II(27.3 weeks) and non-NEC (26 weeks), (p=0.0008), had higher severity of illness with Score for Neonatal Acute Physiology Perinatal Extension-II (SNAPPE-II score) of 47.5 versus 28.4 for NEC-II and 37 for non-NEC ( p=0.003), spent more days on vasoactive agents (3.7 days versus 1.1 days and 1.8 days for NEC-II and non-NEC respectively; p=0.05). There was a trend towards lower Apgar score <7 at 10 mintues in NEC-III versus non-NEC (AOR 2.59, 95% CI [0.88-7.67]; p=0.085). Death or short bowel syndrome was higher for NEC III (AOR 12.4, 95% CI [1.16-132.28]; p=0.037). Conclusion In this case-control study of neonates born under 33 weeks GA, after adjustment for known confounders, duration of UAC and prolonged rupture of membranes were significantly associated with increased incidence of NEC-III. Composite outcome of mortality or short bowel syndrome were higher in NEC-III.