An interpretable machine learning model for predicting NICU admission in preterm infants: a single-center retrospective cohort study.

Background: Admission to the neonatal intensive care unit (NICU) is a critical event for preterm infants, with significant implications for resource allocation and parental counseling. However, existing prediction tools are often limited by low accuracy or lack of interpretability. This study aimed to develop an interpretable machine learning (ML) model for predicting NICU admission in preterm infants using readily available prenatal and intrapartum features, with a focus on both the overall cohort and the clinically challenging subgroup of late preterm infants (34-37 weeks). Methods: A retrospective cohort of 2,610 preterm infants was analyzed. Features were selected using Boruta and least absolute shrinkage and selection operator (LASSO). Multiple models were trained and optimized via 5-fold cross-validation. The optimal model was evaluated using area under the curve (AUC), calibration, and decision curve analysis. Subgroup analysis was performed in late preterm infants (34-37 weeks) to assess model performance in this population. Interpretability was assessed with Shapley Additive exPlanations (SHAP). Results: The random forest (RF) model demonstrated superior and robust performance, achieving an AUC of 0.861 [95% confidence interval (CI): 0.830-0.891] in the validation set and 0.869 (0.841-0.897) in the testing set. SHAP analysis identified birth weight (mean |SHAP| value =0.17), prenatal checkup status (0.13), and gestational age (0.09) as the three most influential predictors. Low birth weight, lack of prenatal care, and gestational age below 32 weeks were associated with a significantly elevated risk of NICU admission. In the late preterm subgroup (34-37 weeks), the RF model maintained robust performance with an AUC of 0.842 (validation) and 0.838 (test), demonstrating good calibration and positive net benefit on decision curve analysis. Conclusions: The interpretable ML model developed in this study accurately identifies preterm infants at high risk of NICU admission, with consistent performance in the late preterm subgroup. By providing individualized risk quantification and visual explanation via SHAP, it facilitates timely clinical decision-making and enhances clinician-parent communication. This tool holds significant potential for optimizing resource allocation and improving perinatal care pathways.