Does SOFA-2 Improve Mortality Prediction in Sepsis? A Retrospective Single-Center Observational Cohort Study Comparing SOFA-1 and SOFA-2

Abstract Background: The Sequential Organ Failure Assessment (SOFA) score has been widely used for nearly three decades to evaluate organ dysfunction and predict mortality in patients with sepsis. Advances in critical care practice have led to the development of an updated version, SOFA-2, incorporating contemporary organ support strategies and revised clinical thresholds. However, real-world comparative data evaluating the prognostic performance of the original SOFA score (SOFA-1) and SOFA-2 remain limited. This study aimed to compare the ability of SOFA-1 and SOFA-2 to predict intensive care unit (ICU), 28-day, and 90-day mortality in patients with sepsis. Methods: This retrospective, single-center observational cohort study included adult patients (≥18 years) diagnosed with sepsis according to Sepsis-3 criteria and admitted between December 2023 and August 2024. SOFA-1 and SOFA-2 scores were calculated using clinical and laboratory data obtained at ICU admission. The primary outcome was ICU mortality; secondary outcomes were 28-day and 90-day mortality. Multivariable logistic regression was performed to identify independent predictors of mortality. Discriminatory performance was assessed using receiver operating characteristic analysis, and areas under the curve were compared using DeLong’s test. Optimal cut-off values were determined using the Youden index. Results: Among 417 screened patients, 222 met the inclusion criteria. ICU mortality was 57.7%. Each one-point increase in SOFA-1 and SOFA-2 scores was associated with a 42% and 43% increase in ICU mortality, respectively (p<0.001 for both). The area under the curve for ICU mortality prediction was 0.843 (95% confidence interval 0.792–0.895) for SOFA-1 and 0.845 (95% confidence interval 0.795–0.896) for SOFA-2, with no statistically significant difference between the two scores (p=0.79). SOFA-2 demonstrated slightly higher specificity, whereas SOFA-1 showed marginally higher sensitivity at the optimal cut-off value. Conclusions: Both SOFA-1 and SOFA-2 demonstrated good discriminatory performance for predicting ICU mortality in patients with sepsis. Although SOFA-2 provided a more balanced sensitivity–specificity profile, its overall predictive performance was comparable to that of SOFA-1. Further prospective multicenter studies are warranted to clarify the incremental clinical value of the updated score. Trial registration : Not applicable.