Clinical characteristics and risk factors for intensive care unit admission and mortality in rapid response team-activated ward patients: a retrospective cohort study at a tertiary hospital in South Korea.

Abstract

Background Factors driving intensive care unit (ICU) transfer decisions and mortality after rapid response team (RRT) activation remain unclear. We identified independent predictors of ICU admission, 28-day mortality, and in-hospital mortality in RRT-activated ward patients. Methods This retrospective cohort study included adults with first RRT activation from September 2023 to August 2025 at a Korean tertiary hospital (n=549). Multivariable logistic regression with backward elimination was used. Results Of 549 patients, 191 (34.8%) were transferred to the ICU. ICU admission was independently predicted by procalcitonin >0.5 ng/ml (adjusted odds ratio [aOR], 2.833; P=0.021) and lower hemoglobin (aOR, 0.808 per g/dl; P=0.040), whereas solid tumor was associated with lower transfer likelihood (aOR, 0.142; P<0.001). Mortality did not differ significantly between ICU and ward groups at 28 days (27.7% vs. 27.7%, P=0.937) or during hospitalization (46.1% vs. 40.2%, P=0.162). Declining peripheral oxygen saturation (SpO₂)/fraction of inspired oxygen (FiO₂) ratio, rising lactate, and hyperkalemia predicted both mortality outcomes. Lower platelet count uniquely predicted 28-day mortality, whereas solid tumor, chronic kidney disease, and deep learning-based continuous cardiac arrest risk score (DeepCARS) additionally predicted in-hospital mortality. ICU admission itself was not independently associated with mortality. Conclusions ICU transfer after RRT activation appears to reflect acute reversibility, clinical trajectory, and possible at/after-activation goals-of-care processes rather than severity alone. Mortality was more closely associated with oxygenation failure, hypoperfusion, and electrolyte instability than with disposition.