Association of C-reactive protein-to-lymphocyte ratio and mortality outcome in patients with trauma admitted to an intensive care unit

Background: Inflammation and immune dysregulation shape outcomes after major trauma, yet practical biomarkers that add prognostic value in the intensive care unit (ICU) are limited. The C‑reactive protein‑to‑lymphocyte ratio (CLR) integrates inflammatory burden and host immune status. This study aimed to evaluate the association between CLR at admission and in‑hospital mortality among adult trauma patients admitted to the ICU, and to characterize the discriminate performance of CLR. Methods: This was a retrospective single‑center cohort study at a level I trauma center in southern Taiwan, including consecutive adults (≥20 years) with traumatic injury admitted to the ICU from 2016–2022. Patients with burns, hanging, drowning, incomplete Injury Severity Score (ISS), or missing laboratory data were excluded. The final analytic cohort comprised 1985 patients (217 deaths, 1768 survivors). Results: Higher CLR was independently associated with mortality (multivariable odds ratio (OR), 1.03; 95%confidence interval (CI), 1.01–1.06; p = 0.021). Other independent predictors included older age, end-stage renal disease, lower Glasgow Coma Scale score, and higher ISS. Receiver operating characteristic (ROC) analysis identified a CLR cutoff of 93.6 with high specificity but low sensitivity (specificity, 0.874; sensitivity, 0.230; area under curve (AUC), 0.515). Compared with CLR <93.6, CLR ≥93.6 was associated with higher adjusted odds of death (adjusted OR, 1.71; 95% CI, 1.16–2.51; p = 0.007) and longer length of stay (mean 24.4 vs. 18.9 days; p < 0.001). Survival curves differed significantly between CLR groups (log-rank p = 0.007). Conclusions: Admission CLR correlates with mortality risk and prolonged hospitalization in ICU trauma patients, but its standalone discriminative performance is poor. CLR may help flag a high‑risk subgroup given its specificity, yet it should be used only in conjunction with established clinical variables and injury‑severity measures. Prospective, multicenter studies with serial CLR measurements and comparison to other inflammatory ratios are warranted.

Trauma; Mortality; Prognosis; Intensive care unit; Injury severity score; C-reactive protein-to-lymphocyte ratio

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