Etiologic spectrum and in-hospital mortality of altered level of consciousness in the emergency department: a single-center retrospective observational study.

BACKGROUND: Altered level of consciousness (ALC) is a common and clinically heterogeneous presentation in emergency departments (EDs). However, large-scale data characterizing etiologies and associated outcomes are limited. METHODS: We retrospectively analyzed 4,226 patients who presented with ALC in a tertiary ED between February 2018 and March 2022. The etiologies were categorized into 10 predefined groups. Mortality was assessed across the care pathway (death in the ED and death after admission) and factors independently associated with in-hospital death were examined using multivariable logistic regression (age [continuous variable], sex, admission destination, and etiology). RESULTS: Traumatic brain injury (TBI) was the most common etiology (21.9%), followed by stroke (15.6%), metabolic causes (14.3%), toxic causes (13.3%), and systemic infection (12.5%). The overall mortality was 22.0%. The total mortality was highest for systemic infection (31.8%), followed by TBI (29.9%), stroke (29.6%), and cardiogenic and vascular (C&V) causes (28.2%); C&V had the highest ED death rate (12.7%). In-hospital mortality increased with age after adjustment (adjusted odds ratio [aOR], 1.19 per decade) and was independently highest for systemic infection (aOR, 1.42), whereas TBI and stroke were not independently elevated. CONCLUSION: ALC in the ED has diverse etiologies and is associated with high mortality rates. Increasing age and systemic infection were the principal independent correlates, whereas the admission destination reflected illness severity rather than outcomes.