Abstract
BACKGROUND: The incidence of necrotizing enterocolitis (NEC) is significantly associated with gestational age (GA). This study aimed to investigate risk factors for surgically treated NEC (sNEC) in extremely preterm infants (EPIs) using nationwide cohort registry. METHODS: Data were collected from 16,338 very-low-birth-weight infants registered in the Korean neonatal network. Clinical data of 5310 EPIs were retrospectively analyzed. sNEC was defined as infants with diagnosis of NEC requiring surgical treatment, who underwent surgical intervention for NEC or died before surgery. Infants were categorized into three groups based on their NEC status: infants without NEC (control), medically treated NEC (mNEC), and sNEC. These groups were matched based on GA to investigate risk factors for NEC. RESULTS: In EPIs, small for gestational age (SGA; odds ratio 1.68, 95% confidence interval [CI], 1.17-2.36, p = 0.004), hypotension (1.49, 1.18-1.89, p = 0.001), and IVH (1.63, 1.30-2.05, p < 0.001) were identified as risk factors for sNEC. Complete administration of antenatal steroid reduced the risk of sNEC (0.80, 0.64-0.99, p = 0.044). CONCLUSION: Our study demonstrated that EPIs who are SGA, and experience hypotension and IVH may be at an increased risk of developing NEC requiring surgery. These groups require close attention and monitoring for any signs of surgical indications of NEC. IMPACT: This nationwide cohort study aimed to identify characteristics of infants with necrotizing enterocolitis (NEC) among extremely preterm infants (EPIs) and analyze the risk factors associated with NEC requiring surgical intervention. Small for gestational age (SGA), hypotension, and intraventricular hemorrhage (IVH) were identified as significant risk factors for surgically treated NEC (sNEC) in EPIs. The administration of antenatal steroids decreases the risk of sNEC. Close attention and monitoring for EPIs with early identifiable risk factors such as SGA, hypotension, and IVH should be considered to prevent and detect sNEC early, ultimately leading to improved long-term outcomes.