Impact of emergency department-to-intensive care unit transfer time on in-hospital mortality: A retrospective cohort study

We evaluated whether emergency department (ED)-to-intensive care unit (ICU) transfer time is associated with in-hospital mortality among adults admitted with ICU-level indications, using a prespecified 4-hour quality threshold. In this retrospective cohort from a tertiary academic hospital (January-December 2023), we analyzed 376 adults admitted to the ICU from the ED. Demographics, comorbidities, primary diagnoses, laboratory markers, and ED process metrics were extracted. ED length of stay (ED-LOS) was examined continuously and categorically (≤4 vs >4 hours). Multivariable logistic regression identified independent predictors of mortality. Overall in-hospital mortality was 54.3%. Median ED-LOS was 194 minutes in survivors versus 220 minutes in non-survivors. While continuous ED-LOS was not significantly different between groups, ED-LOS > 4 hours was independently associated with increased mortality (odds ratio, 1.78; 95% confidence interval, 1.13-2.82; P = .01). Additional predictors included advanced age, sepsis diagnosis, low serum albumin, and acute physiology and chronic health evaluation II ≥ 35; presentation during daytime hours was associated with reduced mortality (odds ratio, 0.54; 95% confidence interval, 0.30-0.97; P = .04). ED-to-ICU transfer delays > 4 hours are independently associated with higher in-hospital mortality. While timely ICU admission is critical, optimizing care during ED boarding may mitigate risk. These findings support system-level interventions targeting ICU transfer within 4 hours for critically ill patients.