Clinical Frailty and Readmission After Planned Postoperative Intensive Care Unit Admission: An Exploratory Retrospective Study

Aim: Readmission to intensive care unit (ICU) after discharge is an indicator of increased mortality and prolonged hospitalization. While perioperative assessment traditionally focuses on acute physiological parameters, frailty has emerged as a marker of reduced physiological reserve and vulnerability to decompensation. This study aims to assess the relationship between frailty and ICU readmission in elective surgical patients with planned ICU admission.Material and Methods: This retrospective observational study included patients admitted to ICU after elective surgery between January 2021 and January 2024. Demographics, comorbidities, perioperative data, Clinical Frailty Scale (CFS), APACHE II, SAPS II scores were collected. ICU readmission during the same hospitalization was the primary outcome. Analyses were considered exploratory due to low number of readmission events.Results: Of 1360 screened patients, 145 with complete data were included. ICU readmission occurred in four patients (2.8%). Readmitted patients had longer ICU and hospital stays and higher mortality. Although preoperative CFS did not differ significantly between patients with and without ICU readmission, the median values corresponded to clinically different frailty categories (6 vs. 3; p=0.067). Readmitted patients had longer initial ICU stays and higher initial illness severity scores.Conclusion: ICU readmission after planned postoperative ICU admission was uncommon but was associated with poor clinical outcomes. Although the difference in CFS did not reach statistical significance, the observed CFS pattern may be clinically relevant but should be interpreted as exploratory because of the low number of readmission events. Larger multicenter studies are needed to clarify the role of frailty assessment in ICU discharge planning and postoperative risk stratification.