Mortality Prediction Using SOFA Score in Critically Ill Surgical and Non-Surgical Patients: Which Parameter Is the Most Valuable?

Background and Objectives: assessment systems, such as the Sequential Organ Failure Assessment (SOFA) scale, are routinely used in intensive care units (ICUs) worldwide in order to predict patients’ outcome. We aimed to investigate SOFA’s usefulness in the prognostication of ICU mortality, including an analysis of the importance of its variables. Materials and Method: this single-centre observational study covered 905 patients that were admitted from 01.01.2015 to 31.12.2017 to a tertiary mixed ICU. The SOFA score was calculated on ICU admission. The worst results recorded within 24 h post admission were included into the calculation. The assessment was performed within subgroups of surgical (SP) and non-surgical patients (NSP). The subjects were followed-up until ICU discharge or death. ICU mortality was considered to be the outcome. Results: ICU mortality reached 35.4% (i.e., 320 deceased out of 905 ICU stays) and it was significantly lower in SP (n = 158, 25.3%) as compared with NSP (n = 162, 57.9%) (p < 0.001). A one-point increase in the SOFA score resulted in 1.35 times higher risk of death in the ICU in the whole studied population. Among the individual variables of SOFA, creatinine concentration was the most powerful in prognostication (OR = 1.92) in univariate analysis, while the Glasgow Coma Scale (GCS) score appeared to be the most important variable in multivariate analysis (OR = 1.8). Mortality prediction using consecutive SOFA variables differed between SP and NSP, as well as between men and women. Conclusions: The overall SOFA score predicts mortality to a similar extent in both surgical and non-surgical subjects. However, there are significant differences in prognostication using its particular components.