Comparison of four scoring systems for predicting ICU mortality in patients with sepsis

Abstract

To evaluate the value of Sequential Organ Failure Assessment (SOFA), Simplified Acute Physiology Score Ⅱ (SAPS-Ⅱ), Oxford Acute Severity of Illness Score (OASIS) and Logistic Organ Dysfunction System (LODS) scoring systems for predicting ICU mortality in patients with sepsis. We collected the data of a total of 2470 cases of sepsis recorded in the MIMIC-III database from 2001 to 2012 and retrieved the scores of SOFA, SAPS-Ⅱ, OASIS and LODS of the patients within the first day of ICU admission. We compared with the score between the survivors and the non-survivors and analyzed the differences in the area under the ROC curve (AUC) of the 4 scoring systems. Binomial logistic regression was performed to compare the predictive value of the 4 scoring systems for ICU mortality of the patients. In the 2470 patients with sepsis, 1966 (79.6%) survived and 504 (20.4%) died in the ICU. Compared with the survivors, the non-survivors had a significantly older mean age, higher proportion of patients receiving mechanical ventilation, and higher initial lactate level, creatinine, urea nitrogen, SOFA score, SAPS-Ⅱ score, OASIS score and LODS score (P < 0.05) but with significantly lower body weight and platelet counts (P < 0.05). The AUCs of the SOFA score, SAPS-Ⅱ score, OASIS score, and LODS score were 0.729 (P < 0.001), 0.768 (P < 0.001), 0.757 (P < 0.001), and 0.739 (P < 0.001), respectively. The AUC of SAPS-Ⅱ score was significantly higher than those of SOFA score (Z=3.679, P < 0.001) and LODS score (Z=3.698, P < 0.001) but was comparable with that of OASIS score (Z=1.102, P=0.271); the AUC of OASIS score was significantly higher than that of LODS score (Z=2.172, P=0.030) and comparable with that of SOFA score (Z=1.709, P=0.088). For predicting ICU mortality in patients without septic shock, the AUC of SAPS-Ⅱ score was 0.769 (0.743-0.793), the highest among the 4 scoring systems; in patients with septic shock, the AUCs SAPS-Ⅱ score and OASIS score, 0.768 (0.745-0.791) and 0.762 (0.738-0.785), respectively, were significantly higher than those of the other two scoring systems. Binomial logistic regression showed the corrected SOFA, SAPS-Ⅱ, and OASIS scores, but not LODS scores, were significantly correlated with ICU mortality in patients with sepsis, and their ORs were 1.08 (95% CI: 1.03-1.14, P=0.001), 1.04 (95% CI: 1.02-1.05, P < 0.001), 1.04 (95% CI: 1.01-1.06, P=0.001), 0.96 (95% CI: 0.89-1.04, P=0.350), respectively. The scores of SOFA, SAPS-Ⅱ, OASIS, and LODS can predict ICU mortality in patients with sepsis, but SAPS-Ⅱ and OASIS scores have better predictive value than SOFA and LODS scores.