Effect of Prolonged Emergency Department Stays on Mortality and In-Hospital Complications in Geriatric Patients: A Prospective Analysis

Background Prolonged emergency department (ED) stay may worsen outcomes in older adults. This study evaluated whether ED stay ≥ 24 h is associated with 30-day in-hospital mortality and complications in patients aged ≥ 65 years. Methods This study enrolled 732 consecutive adults aged ≥ 65 years presenting to a university ED (March 15–June 30, 2025) and stratified into having ED stay of ≥ 24 h and < 24 h. Demographics, presenting complaints, vital signs, comorbidities, and admission scores (Charlson comorbidity index [CCI], national early warning score 2 [NEWS-2], pan-immune-inflammation value [PIV], and clinical frailty scale [CFS]) were recorded. The primary outcome was 30-day in-hospital mortality, and the secondary outcomes were in-hospital complications (infections, acute kidney injury, dysnatremia, falls, acute myocardial infarction, cerebrovascular events, deep vein thrombosis, pulmonary embolism, and pressure ulcers). Results The 30-day in-hospital mortality rate was higher with prolonged ED stay (13.4% vs. 5.7%; p < 0.001). Complications were also more frequent (32.5% vs. 21.0%; p < 0.001). ED stay ≥ 24 h remained independently associated with higher mortality. Higher NEWS-2, CCI, and CFS scores were significant predictors, whereas the PIV was not. Infection-related, respiratory, and impaired general-condition presentations were associated with adverse outcomes. Conclusions Prolonged ED stay and higher NEWS-2, CCI, and CFS scores on admission indicate increased 30-day mortality and complications. Impaired general condition, infection on presentation, and chronic kidney disease further flag the complication risk. Embedding these routine indicators in ED workflows may improve early risk stratification in older adults.