Consideration of additional factors in Sequential Organ Failure Assessment score

Abstract

Purpose: The Sequential Organ Failure Assessment (SOFA) score, originally developed to assess organ failure status, is widely used as a prognostic indicator in intensive care unit patients. Additional prognostic factors, such as age and comorbidities, may complement the predictive performance of the SOFA.

Methods: In total, 1049 consecutive patients were enrolled prospectively. SOFA and other admission-based intensive care unit scores were recorded during the first 24 hours. A complemented SOFA (cSOFA) score model was constructed by adding age and comorbidity scores to the original SOFA score, based on logistic regression analysis. The predictive performance was evaluated with regard to hospital mortality by receiver operating characteristics analysis. The Hosmer-Lemeshow goodness-of-fit test was used to assess calibration of the model, and leave-one-out cross-validation was performed.

Results: The cSOFA score (maximum 30 points) was calculated as the SOFA score (24 points) + age score (2 points) + comorbidity score (4 points). The cSOFA score model showed satisfactory calibration and cross-validation performance. The AUC (95% CI) of the cSOFA score (0.812 [0.787-0.835]) was higher than the SOFA score (0.743 [0.715-0.769], P < .0001).

Conclusion: The performance of the SOFA score to predict hospital mortality can be improved by considering age and comorbidity factors.

Keywords: Illness index severities; Intensive care unit; Multiple organ failures; Outcome assessments; Scoring method.