The associations between cytokine levels and clinical outcomes in critically ill patients after surgery: a retrospective cohort study

Abstract

Background The associations of serum cytokine levels and critically ill patient outcomes after surgery remain unclear. The use of cytokine markers to predict outcomes in critically ill patients is controversial. Objective To determine the levels of IL-1β, IL-2, IL-6, IL-8, IL-10, TNF-α and procalcitonin in critical surgical ICU (SICU) patients and evaluate their associations with patient outcome and clinical significance. Methods This was a retrospective cohort study of consecutive patients admitted to the SICU in Zhongshan Hospital, Fudan University. The program ran from January 1, 2018, to June 30, 2019. The levels of IL-1β, IL-2, IL-6, IL-8, IL-10, TNF-α and procalcitonin were detected, and their relationship with patient outcomes was investigated. The primary outcome was in-hospital mortality, compared by a multivariable logistic regression analysis among the survivors and nonsurvivors. Results Overall, 5,257 patients were included in this study for their first SICU admission; 5,099 patients survived, 158 patients died, and the mortality rate was 3.0% (158/5,257). Univariate and multivariate analyses showed that nonsurvivors had increased levels of IL-1β (OR = 1.855, P = 0.000) and IL-2 (OR = 1.51, P = 0.000) compared with survivors. In addition, 196 patients (3.7%) were readmitted to the SICU, and data from 187 patients were collected. Of these, 161 patients survived, and 26 patients died; the mortality rate was 13.9% (26/187), which was much higher than that of the first round of patients. The level of IL-2 significantly influenced SICU readmission (OR = 3.921, P = 0.000). For the third round of SICU admission, 10 patients were included, 7 patients survived, and 3 patients died; the mortality rate was 30.0% (3/10). Furthermore, older age, longer time of SICU stay, and higher rate of mechanical ventilation and CRRT were associated with patient death. Conclusions High levels of cytokines may be risk factors for mortality and SICU readmission in critically ill patients who receive surgery. Further work is still needed to determine which unmeasured characteristics and therapies may contribute to the increased risk observed.