Is C-reactive protein-albumin ratio or neutrophil-lymphocyte ratio a better indicator to predict in-hospital mortality in traumatic brain injury?

Background: Neutrophil-lymphocyte ratio (NLR) and C-reactive protein-albumin ratio (CAR) are simple and objective markers of inflammatory responses. However, there are no studies in the literature evaluating these two markers together in traumatic brain injury (TBI). Therefore, this study aimed to examine whether CAR or NLR is a better biomarker for predicting in-hospital mortality in patients with TBI.

Methods: A total of 257 consecutive patients admitted to the hospital between January 2016 and December 2021 were included in the study. The files of all patients aged >18 years with TBI were retrospectively reviewed. Clinical characteristics, Glasgow Coma Scale, and patient data during hospital stay were recorded. Definitive diagnosis was made using computed brain tomography. Routine blood tests were performed in the first 12-24 h of hospitalization. Laboratory results of patients with and without in-hospital mortality were comparatively analyzed.

Results: According to the Mann-Whitney U-test, median CRP, CAR, NLR, WBC, monocyte, neutrophil, RDW-CV, RDW-SD, and platelet values were significantly higher, whereas median albumin and RBC values were significantly lower in patients with in-hospital mortality. Student's t-test showed that the mean hemoglobin level was significantly lower in patients with in-hospital mortality compared to other patients. Univariate logistics regression model revealed that age, albumin, CRP, CAR, NLR, WBC, monocyte, neutrophil, RBC, RDW-CV, RDW-SD, and hemoglobin were the factors predicting mortality. However, in the multivariate logistic regression model, only age, albumin, CAR, and WBC were the factors predicting mortality. Areas under the curve were 0.891 for CAR (95% GA, 0.847-0.935), 0.759 for WBC (95% GA, 0.696-0.823), and 0.671 for NLR (95% GA, 0.598-0.744).

Conclusion: The results of this study showed that CAR has better prognostic value than NLR in predicting in-hospital mortality in patients with TBI.