Association Between Emergency Department-to-ICU Transfer Time and Hospital Mortality Across ICU Admission Diagnoses: A Post Hoc Subgroup Analysis

OBJECTIVES: To assess the association between emergency department (ED)-to-ICU transfer time and hospital mortality across common ICU diagnoses. DESIGN, SETTING, AND PATIENTS: Secondary analysis of a Dutch retrospective cohort (2009-2020). Twelve hospitals (four academic and eight nonacademic teaching [NACT]) provided ED arrival and ICU admission times. Adult patients directly admitted from the ED to the ICU were included. Seven diagnostic groups (> 1500 patients each) were analyzed: out-of-hospital cardiac arrest (OHCA), nonoperative trauma, overdose, sepsis, pneumonia, respiratory failure (excluding pneumonia), and intracranial hemorrhage (ICH). Logistic regression assessed associations between ED-to-ICU time quintiles and hospital mortality, adjusting for hospital of admission, and Acute Physiology and Chronic Health Evaluation III score. Analyses were stratified by hospital type. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among 18,798 patients, median ED-to-ICU time was 1.9 hours (interquartile range, 1.2-3.1 hr). In OHCA (n = 3,818), associations differed by hospital type. In academic hospitals, prolonged ED-to-ICU time was associated with higher mortality (odds ratio [OR], 1.48; 95% CI, 1.08-2.02 at 1.1-1.6 hr; OR, 2.94; 95% CI, 1.80-4.78 at > 3.4 hr; Wald χ2p < 0.001). In NACT hospitals, prolonged ED-to-ICU time was negatively associated with mortality, with ORs less than 1.0 across quintiles (Wald χ2p < 0.001). In nonoperative trauma, a positive association between ED-to-ICU time and hospital mortality was observed in the overall cohort (OR, 1.90; 95% CI, 1.12-3.21 at > 3.4 hr; Wald χ2p = 0.05) but was not reproduced after stratification for hospital. No associations were observed in overdose, sepsis, pneumonia, respiratory failure, or ICH. CONCLUSIONS: The association between ED-to-ICU time and hospital mortality varied across diagnostic groups and hospital types. In OHCA, opposing associations were observed in academic and NACT hospitals. In nonoperative trauma, a positive association was observed only in the overall cohort. Prospective studies in homogeneous, risk-defined subgroups with detailed process-of-care data are needed to identify modifiable delays and define transfer-time thresholds.