Abstract
BACKGROUND: Globally, there is an increasing number of critically ill patients being treated in Emergency Departments (EDs), resulting in poor quality of care and a high mortality rate. This study investigates the incidence of mortality and independent predictors of 30-day mortality in critically ill patients after admission to the ED in the central region of Thailand. METHODS: A prospective observational study was conducted of non-trauma critically ill patients, and followed their outcomes of 30-day mortality after admission to the ED. The Kaplan-Meier estimated survival probability and Cox proportional hazards model analyzed and investigated risk factors associated with 30-day mortality. RESULTS: A total of 442 patients were included. The 30-day mortality rate was 11.1%, with an incidence rate of 4.0 per 1,000 person-days (95% CI 2.93–5.24). Independent predictors of mortality were altered consciousness (aHR 3.25; 95% CI 1.64–7.15), Emergency Severity Index (ESI) level 1 (aHR 2.38; 95% CI 1.21–4.68), sepsis or septic shock (aHR 2.60; 95% CI 1.07–3.99), National Early Warning Score (NEWS) ≥ 5 at ED discharge (aHR 2.03; 95% CI 1.02–4.04), and higher Charlson Comorbidity Index (CCI) scores (aHR 1.38; 95% CI 1.17–1.64). Inter-hospital transfer demonstrated the strongest association with mortality (aHR 4.70; 95% CI 2.35–9.41). These findings provide region-specific incidence estimates and quantify both patient- and healthcare system-level risks, thereby addressing a critical evidence gap in emergency care in central Thailand. CONCLUSIONS: This study has identified key predictors of 30-day mortality among critically ill patients following ED admission and provides region-specific evidence from central Thailand, where data remain limited. The strong association between inter-hospital transfer and mortality highlights a previously underrecognized weakness in regional referral pathways. Furthermore, the prognostic value of NEWS at ED discharge offers practical utility for early risk stratification in ED settings. These context-specific insights support ongoing efforts to enhance early risk identification and strengthen referral processes to reduce preventable mortality.