Early risk stratification of necrotizing enterocolitis using 48-h laboratory indicators and pre-symptom clinical-course variables: a single-center retrospective study

Early identification of neonates at risk of necrotizing enterocolitis (NEC) is challenging due to nonspecific early gastrointestinal manifestations. This study aimed to develop and internally validate a nomogram for identifying neonates at increased risk of NEC using early postnatal clinical and laboratory information. This single-center retrospective study included neonates admitted to the neonatal intensive care unit of Southwest Hospital between January 2018 and January 2024 who developed suspected NEC or feeding intolerance–related gastrointestinal manifestations. NEC was defined as Modified Bell stage II or III disease. Controls were neonates with Modified Bell stage I disease or other gastrointestinal manifestations, such as vomiting, regurgitation, or abdominal distension, without progression to NEC. Candidate predictors included perinatal characteristics, feeding-related variables, pre-symptom clinical-course variables, and routine laboratory indicators measured within 48 h after birth. Multivariable logistic regression was used to construct the nomogram, and model performance was assessed using discrimination, calibration, decision curve analysis, and bootstrap internal validation. A total of 248 neonates were included, including 77 with NEC and 171 controls. Of the included neonates, 14.1% were born at < 32 weeks of gestation and 13.3% had a birth weight < 1500 g. The final nomogram incorporated five predictors: 5-min Apgar score, parenteral nutrition, feeding advancement rate, neutrophil percentage, and procalcitonin. The apparent AUC was 0.839 (95% CI, 0.785–0.893), and the bootstrap optimism-corrected AUC was 0.826. At the optimal cutoff value of 0.353, the sensitivity and specificity were 71.4% and 86.0%, respectively. Calibration analysis indicated acceptable agreement between predicted and observed risks, and decision curve analysis suggested potential clinical usefulness. A nomogram combining early postnatal laboratory indicators and pre-symptom clinical variables showed good internal performance for NEC risk stratification. External validation, particularly in very-preterm and very-low-birth-weight populations, is required before clinical implementation.