Development of an Extended Cardiovascular SOFA Score Component Reflecting Cardiac Dysfunction with Improved Survival Prediction in Sepsis: An Exploratory Analysis in the Sepsis and Elevated Troponin (SET) Study

Introduction The cardiovascular component of the Sequential Organ Failure Assessment (SOFA) score does not correspond with contemporary clinical practice in sepsis or identify impaired cardiac function. Our aim was to develop a modified cardiovascular SOFA component that reflects cardiac dysfunction and improves the SOFA score's 30-day mortality discrimination. Methods A cohort of sepsis patients from a previous study was divided into a training (n = 250) and test cohort (n = 253). Nine widely available measures of cardiovascular function were screened for association with 30-day mortality using natural cubic spline. High-sensitivity cardiac troponin T (hs-cTnT), N-terminal pro B-type natriuretic peptide (NT-proBNP) and heart rate (HR) were transformed into ordinal variables (0-4 points). The presence of atrial fibrillation (AF) was assigned two points. The SOFA score was extended by adding the variable points in different weights and combinations. The best-performing cardiac-extended model (CE-SOFA) was evaluated in the test cohort. Improved prognostic discrimination and calibration were assessed using logistic regression, area under receiver operating characteristic curves (AUC), Net Reclassification Improvement (NRI) index, and DeLong and Hoshmer-Lemeshow tests. Results In the training cohort, all differently weighted and combined models using hs-cTnT, NT-proBNP and AF points added to the SOFA score showed improved discriminative ability (AUC 0.67-0.75) compared to the SOFA score (AUC 0.62; NRI P < .001; DeLong P ≤ .001). In the test cohort, CE-SOFA demonstrated improved 30-day mortality discrimination compared to the SOFA score (AUC 0.72 vs 0.68), exhibiting good calibration and significantly improved discrimination using the NRI index ( P = .009) but not the DeLong test ( P = .142). Conclusions The CE-SOFA model reflects cardiac dysfunction and improves 30-day mortality discrimination in sepsis. External validation is the next step to further substantiate a revised cardiovascular component in a future SOFA 2.0.