Readmissions to a Surgical Intensive Care Unit: Incidence and Risk Stratification for Personalized Patient Care

Background/Objectives: Unplanned readmission to the surgical intensive care unit (UR-SICU) is a serious adverse event linked to higher morbidity, prolonged stay, and increased mortality. Most evidence derives from mixed ICUs, limiting applicability to surgical cohorts. We aimed to identify risk factors for UR-SICU and assess their impact on outcomes. Methods: We performed a retrospective cohort study of adults admitted to a 20-bed SICU in a tertiary hospital between June 2021 and December 2022 after non-cardiac surgery (elective, urgent, trauma, or liver transplantation). Patients dying during the first SICU stay or transferred to another ICU were excluded. Demographics, comorbidities, severity scores, treatments, and complications were recorded. Logistic regression identified predictors. Kaplan–Meier curves analyzed survival. Results: Among 1361 patients, 82 (6.4%) required UR-SICU. Half were surgical (mainly hemorrhage and sepsis), while respiratory and infectious complications predominated among medical readmissions. Independent predictors for UR-SICU were age (OR 1.03/year; p = 0.002), active malignancy (OR 1.79; p = 0.012), and delirium during the first SICU stay (OR 1.86; p = 0.030). UR-SICU patients had longer hospital stays 46 vs. 13 days; p < 0.001 and higher hospital mortality (27.1% vs. 1.48%; OR 24.68; p < 0.001). Mortality remained higher at 6 months (33.3% vs. 7.1%) and 1 year (42.3% vs. 11.1%). Conclusions: UR-SICU occurred in 6.4% of patients and was independently associated with age, malignancy, and delirium. Readmission was strongly linked to prolonged hospitalization and increased short- and long-term mortality. Early recognition of high-risk patients and targeted, personalized preventive strategies may help reduce avoidable readmissions.