Predictive Value of Combined MEWS and NIPDS Scores for 24-Hour Clinical Deterioration in Emergency Observation Patients: A Prospective Cohort Study

Purpose: To investigate the predictive value of the Modified Early Warning Score (MEWS) combined with the Nurse Intuition Patient Deterioration Scale (NIPDS) for 24-hour deterioration among emergency observation patients. Patients and Methods: This single-center prospective cohort study enrolled 2,415 emergency observation patients at a tertiary care hospital in Nanjing between May and December 2025. Patients underwent serial assessments using MEWS and NIPDS at 0, 2, 4, 8, 16, and 24 hours post-admission. The primary outcome was unplanned transfer to the resuscitation room or ICU or death within 24 hours. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive value of MEWS alone and the combined score for 24-hour deterioration. Results: Among the 2,415 patients, 287 (11.9%) experienced unplanned transfer to the resuscitation room or ICU or died within 24 hours. The combined score showed significantly better predictive performance than MEWS alone (AUC=0.859 vs 0.688, P < 0.001) and improved overall risk reclassification (NRI=0.309, 95% CI: 0.245– 0.373), although event-specific reclassification was modest and did not reach statistical significance (NRI=0.056, 95% CI: − 0.011 to 0.123; P =0.103). Calibration was good (Hosmer–Lemeshow P = 0.287), and decision curve analysis indicated a higher net benefit within the 5%– 40% threshold range. Bootstrap validation confirmed model stability (optimism=0.0008). Conclusion: The combined MEWS and NIPDS score improves overall risk stratification compared with MEWS alone; however, clinical implementation should consider that the incremental reclassification value was driven primarily by correct down-classification of patients who did not deteriorate, while maintaining comparable sensitivity for those who did.