SOFA-2 Versus SOFA-1 for Mortality Prediction in Infection-Triggered ICU Patients

BackgroundAccurate assessment of organ dysfunction is essential for risk stratification in critically ill patients. The traditional Sequential Organ Failure Assessment score (SOFA-1) is widely used but reflects clinical practices from the 1990s. The updated SOFA-2 incorporates revised thresholds aligned with current organ-support strategies; however, its prognostic performance in infection-focused intensive care unit (ICU) populations remains uncertain. We compared SOFA-1 and SOFA-2 for predicting 28-day mortality in ICU patients undergoing blood culture acquisition ≥48 h after admission.MethodsWe conducted a retrospective cohort study of adult ICU patients who underwent blood culture sampling ≥48 h after ICU admission between June 2022 and August 2024. SOFA-1 and SOFA-2 scores were calculated at the time of index blood culture. Mortality prediction was assessed using receiver operating characteristic analysis with paired DeLong comparisons. Associations with 28-day mortality were examined using logistic regression and Cox proportional hazards models adjusted for age and comorbidity burden. Clinical utility was evaluated using decision curve analysis.ResultsAmong 403 patients, 28-day mortality was 54%. SOFA-2 scores were lower than SOFA-1 in 70% of patients, resulting in frequent downward reclassification across severity strata. Discriminative performance for 28-day mortality was similar for SOFA-1 and SOFA-2 (AUC 0.707 vs 0.700; ΔAUC = 0.007; p = .031). Calibration and net clinical benefit were comparable between scores. In adjusted time-to-event analyses, only the very severe category (>10) was independently associated with mortality in both scoring systems, with a numerically higher hazard ratio for SOFA-2.ConclusionsIn this infection-triggered ICU cohort, SOFA-2 did not demonstrate consistent prognostic superiority over SOFA-1 for 28-day mortality prediction. Despite systematic score redistribution, overall discrimination and clinical utility were similar, with any apparent advantage of SOFA-2 confined to the highest-risk subgroup. Further validation in infection-enriched ICU populations is warranted.