Comparison of the Full Outline of UnResponsiveness Score and Glasgow Coma Scale in Predicting Endotracheal Intubation, Hospital Length of Stay, and Mortality Among Patients With Non-traumatic Altered Mental Status in the Emergency Department.

INTRODUCTION: The Glasgow Coma Scale (GCS) is a commonly used assessment tool; however, it has recognized limitations, particularly in patients who are intubated or have aphasia. The Full Outline of UnResponsiveness (FOUR) score was created to tackle these limitations. It has been studied mainly in the trauma and neuroscience setting; to our knowledge, this is the first study to compare the predictive performance of GCS and FOUR scores for endotracheal intubation and length of hospital stay in non-traumatic altered mental status patients in the emergency department (ED). METHODS: A prospective cohort study was conducted among adult patients from May 2024 to July 2025. The area under the receiver operating characteristic (AUROC) curve was used to evaluate and compare the predictive accuracy of the GCS and FOUR scores in predicting outcomes. RESULTS: A total of 240 patients were included in the study. The median age was 70 years (IQR: 21); 55.0% were female. In-hospital mortality was 39.6%. 27.9% of patients required ICU admission. The FOUR and GCS scores both demonstrated significant discriminative ability across outcomes (all p < 0.001). For in-hospital mortality, the FOUR score showed superior accuracy (AUROC 0.851, 95% CI: 0.803-0.900) compared to the GCS (0.771, 95% CI: 0.710-0.831). Similarly, in predicting endotracheal intubation, the FOUR score outperformed the GCS (AUROC 0.875 vs. 0.781). For the length of hospital stay, the FOUR score also demonstrated higher predictive value (AUROC 0.771 vs. 0.734). CONCLUSION: The FOUR score demonstrated superior predictive accuracy compared to the GCS across all clinical outcomes, including mortality, intubation, and length of hospital stay. It may serve as a more reliable tool for prognostication in non-traumatic patients with altered mental status.