Admission nutritional-immunological indices and sepsis risk in emergency trauma patients: a retrospective cohort study

Objective This study aimed to investigate the association of the controlling nutritional status (CONUT) score and prognostic nutritional index (PNI) with the incidence of sepsis in emergency trauma patients, and to evaluate their potential clinical utility for the early prediction of sepsis. Materials and methods The study enrolled trauma patients admitted to the Emergency Department of the Third Hospital of Hebei Medical University in China. CONUT score and PNI were calculated based on serum biomarkers to assess nutritional status. The primary outcome was the incidence of sepsis. Multivariate logistic regression analysis was performed to calculate adjusted odds ratios (OR) with 95% confidence intervals (CI). In addition, threshold effect analysis, subgroup analysis, and ROC curve analysis were conducted. Results A total of 722 trauma patients admitted between January 1, 2021, and November 30, 2023, were included in the analysis. The incidence of sepsis was 33.1%. After adjusting for potential confounders, higher CONUT scores were significantly associated with an increased risk of sepsis (OR: 1.19, 95% CI: 1.04–1.36, p = 0.01), whereas higher PNI values were inversely associated with sepsis risk (OR: 0.88, 95% CI: 0.83–0.94, p < 0.001). Restricted cubic spline analysis demonstrated nonlinear associations of both CONUT and PNI with sepsis incidence. For CONUT <5, each 1-point increase was associated with a 2.43-fold higher odds of sepsis (OR: 2.43, 95% CI: 1.04–5.67, p = 0.0399); for PNI ≥ 39, each 1-unit increase was associated with a 35% lower odds of sepsis (OR: 0.65, 95% CI: 0.45–0.93, p = 0.0177). Subgroup analyses confirmed the robustness of these associations, with no significant interactions detected. Exploratory evaluation based on ROC curve analysis revealed that the AUCs of CONUT score and PNI for discriminating sepsis occurrence in trauma patients were 0.837 (95% CI: 0.808–0.866) and 0.851 (95% CI: 0.824–0.878), respectively. Conclusion Both the CONUT score and PNI were independently associated with sepsis risk in emergency trauma patients and may be useful for early risk stratification. However, these findings are exploratory and require prospective, multicenter validation before clinical application.