C‐reactive protein‐to‐lymphocyte ratio as a prognostic biomarker for mortality in trauma: A retrospective study from a level I trauma center

Objective The C‐reactive protein‐to‐lymphocyte ratio (CLR) combines inflammatory and immune response markers, potentially providing valuable prognostic information for various illnesses. This study evaluated the efficacy of the CLR as a prognostic biomarker for predicting mortality in patients with trauma. Methods This retrospective study analyzed data from 6049 adult patients with trauma (aged ≥ 20 years) in a Level I trauma center in southern Taiwan between 1998 and 2022. The predictive performance of the CLR was assessed using the area under the curve (AUC) of the receiver operating characteristic curve. Univariate and multivariate analyses were performed to identify independent risk factors for mortality. A propensity score‐matched analysis compared the outcomes between the high‐ and low‐CLR groups. Results Deceased patients had significantly higher CLR values than survivors (69.8 vs. 35.5 and p < 0.001). In multivariate analysis, higher CLR remained an independent risk factor for mortality (odds ratio [OR] 1.33, 95% confidence interval: 1.13–1.57, and p = 0.001). The optimal CLR cutoff value for predicting mortality was 54.5, with a sensitivity of 36.4% and a specificity of 80.9% (AUC = 0.596). After propensity score matching, patients with high CLR (≥54.5) had higher mortality rates (8.8% vs. 6.0%, OR 1.51, and p = 0.011) and longer hospital stays (18.7 vs. 14.0 days and p < 0.001) compared to those with low CLR. Conclusion CLR is a potential prognostic marker for patients with trauma, with higher values associated with increased mortality and longer hospital stays. However, its modest predictive power suggests that it should not be used as a stand‐alone predictor. The high specificity of CLR at the optimal cutoff value indicates that it could be valuable for identifying high‐risk patients when used in conjunction with other clinical indicators. Further prospective multicenter studies are needed to validate and refine CLR's role of the CLR in the prognosis of trauma.