Development of a prediction model for surgery or early mortality at the time of initial assessment for necrotizing enterocolitis

Background: No available scale, at the time of initial evaluation for necrotizing enterocolitis (NEC), accurately predicts, i.e., with an area under the curve (AUC) ≥ ≥ 0.9, which preterm infants will undergo surgery for NEC stage III or die within a week. Methods: This is a retrospective cohort study (n=261) of preterm infants <33 weeks' gestation or <1500 grams birthweight with either suspected or with definite NEC born at Parkland Hospital between 2009-2021. A prediction model using the new HASOFA score [Hyperkalemia, Hyperglycemia, use of inotropes for Hypotension during the prior week, Acidemia, neonatal Sequential Organ Failure Assessment (nSOFA) score] was compared with a similar model using the nSOFA score. Results: Among 261 infants, 112 infants had NEC stage I, 68 with NEC stage II and 81 with NEC stage III based on modified Bell's classification. The primary outcome, surgery for NEC stage III or death within a week, occurred in 81 infants (surgery in 66 infants and death in 38 infants). All infants with pneumoperitoneum or abdominal compartment syndrome either died or had surgery. The HASOFA score and the nSOFA score were evaluated in 254 and 253 infants, respectively, at the time of the initial work up for NEC. Both models were internally validated. The HASOFA-model was a better predictor of surgery for NEC stage III or death within a week than the nSOFA-model, with greater AUC 0.909 vs 0.825, respectively, P<0.001. Combining HASOFA at initial assessment with concurrent or later presence of abdominal wall erythema or portal gas improved the prediction surgery for NEC stage III or death with AUC 0.942 or 0.956, respectively. Conclusion: Using this new internally validated prediction model, surgery for NEC stage III or death within a week can be accurately predicted at the time of initial assessment for NEC.