Study of C-reactive protein, procalcitonin, and immunocyte ratios in 194 patients with sepsis

Evidence suggests that C-reactive protein (CRP), procalcitonin (PCT), and immune cells can predict sepsis severity in adult patients. However, the specific values of these indicators are not consistent in predicting prognosis.

A retrospective study analyzed the medical records of 194 patients based on the concept of sepsis in 2016 (Sepsis 3.0) from January 2017 to December 2019. A comparative analysis of inflammatory factors associated with patients in the sepsis survival and the non-survival group was performed. The concentrations of CRP and PCT, neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and platelet-to-lymphocyte ratio (PLR) were measured. ROC curve was used to assess the diagnosis and analysis of the selected indices of sepsis. According to each index's cut-off value of the ROC curve, the patients were divided into two groups, and the prognosis was calculated.

Among the 194 patients, 32 died (16.49%), the median age of the patients was 79 (66.0, 83.3) years, and 118 were male (60.8%). Analysis of related inflammatory indicators showed that CRP, NLR, MLR, PLR, and CRP*PCT in the non-survival group were statistically higher than those in the survival group (all p values were < 0.05). Regression analysis showed that PCT, CRP, NLR, PLR, and CRP*PCT were all independent prognostic factors for patients. The ROC curve results showed that CRP*PCT had the best diagnostic value (AUC = 0.915). The cut-off values of PCT, CRP, NLR, PLR, MLR, and CRP*PCT were 0.25 ng/mL, 85.00 mg/L, 8.66, 275.51, 0.74%, and 5.85 (mg/L)², respectively. Kaplan-Meier survival estimate showed that patient prognosis between the CRP, PCT, NLR, PLR, and CRP*PCT was statistically different (all values P < 0.05, respectively). However, there was no statistically significant difference in gender and MLR (all values P > 0.05, respectively), grouping based on diagnostic cut-off values.

In this study, inflammation-related markers PCT, CRP, NLR, MLR, PLR, and CRP*PCT can be used as independent risk factors affecting the prognosis of patients with sepsis. Furthermore, except for MRL, these indicators have cut-off values for predicting patient death.