External validation of the feeding intolerance prediction model (NOFI) in critically ill patients: A post hoc analysis of a large-scale randomized controlled trial

Feeding intolerance (FI) is associated with poor prognosis of critically ill patients. This study aims to externally validate the performance of a FI model (NOFI), which was developed using primary diagnosis, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and acute gastrointestinal injury (AGI) grade to predict FI occurrence in critically ill patients. The NOFI model was developed using a retrospective cohort and was preliminarily validated in a prospective study. A post hoc analysis was then conducted using data from a multi-center randomized controlled trial to select patients who initiated early enteral nutrition as an external validation dataset. The predictive performance of NOFI was evaluated in terms of discrimination, calibration, and clinical utility. FI risk stratification was defined as follows: The NOFI prediction probability >0.85 (high risk), 0.3–0.85 (middle risk), or