Predictive Value of IL-6+SOFA for Mortality Risk in Critical Ill Patients

Objective: Mortality after critical illness is greatly related to a prediction of disease and clinical decision. We aimed to assess the prognostic value of Interleukin-6 (IL-6) for critically ill patients. Methods: 199 patients with critically ill were included from the emergency department of Beijing Chaoyang Hospital, Capital Medical University from October 2020 to April 2021. IL-6 and other markers were tested immediately after admission. Score Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation II (APACHE II) related to critical illness were calculated. The correlation of monitoring markers and clinical 28-day mortality was analyzed by logistic regression, and the receiver operating characteristic curve (ROC). Results: Among the 199 patients, 139 are dead and 60 are survival within 28 days, respectively. SOFA, APACHE II, systolic blood pressure (SBP), serum calcium, Albumin (ALB), high density lipoprotein (HDL), and IL-6 were significantly different in the non-survival and survival groups (P< 0.05). Logistic regression analysis showed that IL-6, SOFA, APACHE II, and SBP were independent predictors for 28-day mortality in critically ill patients (P< 0.05). The area under curve (AUC) of ROC curve in IL-6 was 0.736 (sensitivity 77%, specificity 66.7%, and cut-off 24.41), which was lower than AUC of ROC curve in SOFA (AUC 0.859, sensitivity 82%, specificity 78.3%, and cut-off 5.5) and APACHE II (AUC 0.767, sensitivity 57.6%, specificity 90%, and cut-off 20.5). The combined evaluation of IL-6+ SOFA had better diagnostic values than IL-6 (Z= 3.799, P= 0.000) or SOFA (Z= 2.283, P= 0.022). Conclusions: IL-6, SOFA and APACHE II are associated with the prognosis of critically ill patients. Compared with the above markers alone, the IL-6+SOFA score has better predictive value.