J. Primus1, I. Caban1, M. Collins1, C. Coghill1,3, C. Roane1, M. Estes1, P. Tarr2, C. Martin1 1Children’s Hospital Of Alabama,Pediatric Surgery,Birmingham, ALABAMA, USA 2Washington University In St. Louis,Pediatric Gastroenterology,St. Louis, MISSOURI, USA 3Children’s Hospital Of Alabama,Neonatal Intesive Care,Birmingham, ALABAMA, USA
Introduction: Necrotizing enterocolitis (NEC) is an inflammatory disorder affecting the GI tract of premature infants and is a significant cause of morbidity and mortality. The development of a mathematical model that can predict the timing of onset in at risk infants can lead to the implementation of directed surveillance strategies and treatments early in life.
Methods: A single institutional retrospective review was conducted which included data from the Children’s Hospital Neonatal Database for Children’s Hospital of Alabama from the years of 2010-2016. Our criteria for perforated NEC and medical NEC was based off of the Vermont Oxford Network criteria. Patients were analyzed based on multiple variables including Apgar scores (categorized as >7 versus ≤7) Birthweight (categorized as Extremely Low Birth Weight with weight<1500 grams versus others with weight ≥1500 grams) and Gestational Age (categorized as Extremely preterm with age<28 weeks versus other with age≥28 weeks). The primary outcome reported was the timing to the diagnosis of NEC. Analyses were done separately for those managed medically and surgically. Kaplan-Meier curves were constructed and log-rank tests were performed to compare the distributions of the time to diagnosis for different categories by Apgar scores 1 and 5, birth weight and gestational age. A parametric survival model was fitted separately for medically and surgically managed patients to examine the relationship between time to diagnosis and Apgar scores 1 and 5, birth weight and gestational age adjusted for covariates such as gender, delivery mode, and insurance type.
Results: Our study included 113 de-identified neonates all of whom developed NEC. Most were treated with surgery (n=82). Of those who underwent surgery 29 died. Medically managed babies with gestational age <28 weeks have a longer time to diagnosis (median 42, 95% CI: 24-56) relative to those with age≥28 weeks (22, 95% CI: 8-27). Similarly, babies with birthweight <1500 grams have a longer time to diagnosis (median 42, 95% CI: 24-56) relative to those with birthweight ≥1500 grams (22, 95% CI: 8-27). For those surgically managed, babies with Apgar scores ≤7 have longer time to diagnosis (median 42, 95% CI: 24-56) relative to those with scores >7 (22, 95% CI: 8-27). In fitting the parametric survival model with all these variables plus gender, insurance type and delivery mode, only Apgar 1 showed to be a significant predictor of the time for those surgically managed.
Conclusion: Although counterintuitive the data suggests that infants at high risk including ELBW, and extreme age may develop NEC later. The retrospective design of this study limits our ability to fully explain this outcome. We speculate that this finding may be due to high surveillance by healthcare providers and less aggressive feeding strategies. Future studies will validate this finding in large multi-institutional administrative databases