Risk Factors and Outcomes of Infants with Necrotizing Enterocolitis: A Case-Control Study

Abstract

Introduction: Necrotizing enterocolitis (NEC) is a condition associated with high mortality and morbidity. Its pathogenesis is linked to intestinal immaturity, inflammation and enteral feeding. Identifying risk factors for the development of NEC and its mortality can inform targeted preventative strategies. Aim: The aim of the study was to assess the incidence, characteristics, risk factors and outcomes of infants diagnosed with NEC in a large tertiary neonatal unit in South Africa. Methods: A prospective case-control study was conducted from May 2022- December 2024 at Chris Hani Baragwanath Academic Hospital. Infants diagnosed with definite NEC (modified Bell’s Stage 2 or 3) were included as cases. Each case was matched with 1-2 controls by weight and postnatal age. Demographic characteristics, laboratory findings, management and outcomes of cases and controls were reviewed. Comparisons were performed between cases and controls, and survivors and non-survivors amongst cases using univariate and multivariate logistic regression analyses. Results: There were 167 cases of NEC enrolled. The incidence of definite NEC was 3.4/1000 live births, 1.4% and 4.0% of all neonatal admissions and very low birth weight infants respectively. The median gestational age, birth weight and postnatal age of cases was 31 weeks, 1455g and 8.5 days respectively. Cases were more likely to have been formula fed (OR 2.00; 95% CI 1.20-3.33); previously exposed to longer duration of antibiotics (OR 1.26; 95% CI 1.14-1.40), having received blood transfusion (OR 27.4; 95% CI 2.09-359) and less likely to have reached full feeds in shorter time (OR-0.88; 95% CI 0.80-0.95). Ninety-one cases (54.5%) had culture-confirmed sepsis. Mortality rate was 49.7%, with ventilation, and hypotension being predictors of mortality Conclusion:. There was a high incidence of definite NEC, with associated high mortality, mainly in infants who were ventilated or hypotensive post NEC diagnosis. Factors associated with NEC were formula feeding, longer duration of antibiotics and prior blood transfusion.