The incidence and modifiable risk factors for necrotizing enterocolitis in preterm infants: a retrospective cohort study

Objectives: To evaluate the incidence and modifiable risk factors for Necrotizing enterocolitis (NEC) in preterm infants born at ≤32 weeks of gestation weighing <1500 grams, at a private tertiary care hospital in Kenya. Materials and methods: This retrospective cohort study was conducted at the Aga Khan University Hospital Neonatal Intensive Care Unit (NICU). Preterm infants born at ≤ 32 weeks’ gestation and weighing <1500 grams admitted to NICU between 2009 and 2019, were recruited into the study. The primary outcome was NEC Bell Stage IIa-IIIb based on Modified Bell’s criteria. Maternal and neonatal characteristics were evaluated. The association between variables of interest and NEC was determined using logistic regression analysis and the incidence of NEC for the study period was calculated. Results: A total of 261 charts of infants born at ≤ 32 weeks’ gestation, weighing <1500 were reviewed, and 200 charts met the inclusion criteria. Fifteen preterm infants developed the primary outcome of interest: NEC Stage ≥2a within the first 30 days of admission. The overall incidence of NEC for the study period was 7.5%. Three risk factors were identified as significantly associated with NEC on multivariate logistic regression analysis: antenatal exposure to steroids (OR = 0.056 CI = 0.003-0.964 p = 0.047), cumulative duration of exposure to invasive mechanical ventilation (OR = 2.172 CI = 1.242-3.799 p = 0.007) and cumulative duration of exposure to umbilical vein catheter (OR = 1.344 CI = 1.08-1.672 p = 0.008). Conclusions: The overall incidence for the study period of NEC Stage ≥ II a was 7.5%. Exposure to antenatal steroids, duration of mechanical ventilation, and duration of umbilical vein catheterization were three independent modifiable risk factors for NEC Stage II a-Stage III b.