Developing Augmented Pro-SOFA and Pro-SAPS Models by Integrating Biomarkers PCT, NLR, and CRP with SOFA and SAPS-III Scores

Background: Sepsis, a life-threatening condition characterized by a dysregulated immune response to infection, remains a significant clinical challenge globally. This study aims to enhance the predictive accuracy of existing sepsis severity scores by developing augmented versions of the SOFA and SAPS-III models, termed Pro-SOFA and Pro-SAPS, through the integration of biomarkers procalcitonin (PCT), neutrophil-tolymphocyte ratio (NLR), and C-reactive protein (CRP). Methods: This prospective observational study was conducted in the medical ICU of a tertiary care hospital in southern India from August 2022 to December 2023. A total of 301 adult patients suspected or confirmed to have sepsis were assessed for eligibility, with 171 patients completing the study. Demographic and clinical data were collected; SOFA and SAPS-III scores were calculated and augmented with PCT, NLR, and CRP to develop Pro-SOFA and Pro-SAPS models. The performance of these models was evaluated using Brier scores, AUC, and net reclassification index (NRI). Results: The augmented Pro-SOFA and Pro-SAPS models demonstrated superior predictive accuracy compared to their original counterparts. The Brier scores for Pro-SOFA and Pro-SAPS were 0.181 and 0.165, respectively, indicating better calibration than the original scores. The Pro- SAPS showed significant improvement over the original SAPS-III score (NRI = 0.50, SE = 0.14, p < 0.01). Similarly, Pro-SOFA outperformed the original SOFA (NRI = 0.49, SE = 0.13, p < 0.01). Conclusion and clinical significance: Integrating PCT, CRP, and NLR with SOFA and SAPS-III scores to develop Pro-SOFA and Pro-SAPS significantly improves the predictive accuracy for sepsis mortality and can thus potentially improve sepsis outcomes.