LIANG Xu, LI Guoqi, ZHANG Hongyu, Kuerbanjiang·TUERXUN
Objective: The aim of this study was to investigate the predictive value of blood lactate, interleukin-6 (IL-6), and the sequential organ failure assessment (SOFA) score on the 28-day mortality risk in sepsis patients. Methods: Retrospective analysis of clinical data of 145 sepsis patients admitted to the Department of Critical Care Medicine at the Second Affiliated Hospital of Xinjiang Medical University. All patients were admitted to the hospital and laboratory tests such as blood gas analysis and routine blood tests were completed and SOFA scores were performed. All patients were followed up for 28 days. Based on survival outcome, the patients were divided into two groups: the survival group (46 cases) and the death group (99 cases). Comparative analysis was then carried out to assess the differences in blood lactate, IL-6, and SOFA scores between the two groups. Univariate and multivariate logistic regression analyses were performed to identify independent factors influencing sepsis patient mortality. Spearman correlation analysis was employed to examine the associations between blood lactate, IL-6, SOFA scores, and sepsis patient mortality. Furthermore, the predictive value of blood lactate, IL-6, and SOFA scores, as well as their combined tests, were evaluated using receiver operating characteristic (ROC) curves. The model underwent 500 resampling iterations using the Bootstrap method in R, followed by the generation of calibration curves and clinical decision curves.Results: Blood lactate levels, IL-6 and SOFA scores of patients in the sepsis death group were significantly higher than those in the survival group, and the differences were all statistically significant (P<0.05). The overall morbidity and mortality rate among patients with sepsis was 68% (99/145). Univariate logistic regression analysis shows diabetes, blood lactate, IL-6, and SOFA score as correlates of death in patients with sepsis. Multivariable logistic regression analysis revealed that high SOFA score, having diabetes mellitus, and high IL-6 were independent risk factors for death in sepsis patients. Furthermore, blood lactate, IL-6, and SOFA scores positively correlated with sepsis patient mortality, while the area under the ROC curve (AUC) for blood lactate, IL-6, SOFA scores, and the combination of the three tests were 0.863, 0.850, 0.897, and 0.949, respectively. The optimal threshold values for lactate, IL-6, and SOFA scores were identified as 2.950 mmol/L, 100.970 pg/mL, and 7.500 points, respectively. The diagnostic sensitivity and specificity for lactate were 77.800% and 89.100%, for IL-6 were 70.700% and 91.300%, and for SOFA score were 93.900% and 80.400%. The combined test exhibited a sensitivity of 90.900% and a specificity of 89.100%. Conclusion: Elevated levels of blood lactate, IL-6, and SOFA scores have been identified as independent risk factors for mortality in patients with sepsis. The clinical prediction model developed in this study demonstrates high accuracy and clinical applicability, while the simultaneous use of these three tests holds significant predictive value in prognostic analysis for sepsis patients.