Jiali Chen,1,2 Jiahui Fu,1,2 Jiazhuo Liu,1,2 Yin Lu,1,2 Dong Han,3 Jiaxuan Zeng,1,2 Zhimin Zou,1,2 Qin Li,1,2 Kun Zhang,1,2 Xiucai Wei,1,2 Li Li,4,5 Zhengtao Gu1,2 

1Department of Treatment Center For Traumatic Injuries, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China; 2Academy of Orthopedics, Guangdong Province, Orthopedic Hospital of Guangdong Province, Guangdong Provincial Key Laboratory of Bone and Joint Degenerative Diseases, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China; 3Department of Quality Control and Evaluation, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China; 4Department of Emergency Medicine, General Hospital of Southern Theatre Command of PLA, Guangzhou, Guangdong, People’s Republic of China; 5Department of Trauma and War Wound Center, General Hospital of Southern Theatre Command of PLA, Guangzhou, Guangdong, People’s Republic of China

Correspondence: Zhengtao Gu, Email guzhengtao@126.com Li Li, Email li_435319585@126.com

Objective: We aimed to investigate the associations between inflammatory immune indicators, specifically systemic immune inflammation index (SII), platelet-to-lymphocyte ratio (PLR) and the coagulopathy and prognosis of traumatic brain injury (TBI) patients in ICU.
Methods: One hundred sixty-one TBI patients were grouped into four groups. The outcomes included TBI-related coagulopathy and prognosis at six months after discharge. The association between SII, PLR and coagulopathy, and prognosis in TBI patients was elucidated by applying trend analysis, sensibility analysis, spearman correlation, restricted cubic splines and so on.
Results: Sixty-four (39.75%) of 161 TBI patients were diagnosed with coagulopathy. In the unadjusted model, TBI patients in the lowest quarter of SII (≤ 966.60) and PLR levels (≤ 97.99) had a higher risk of coagulopathy than those in the highest quarter of SII (≥ 3096.16) [OR 0.169 (95% CI 0.052– 0.547)] and PLR (≥ 255.39) [OR 0.098 (95% CI 0.028– 0.340)]. After adjusting for covariates, the significant negative associations of results remained consistent in the sensitivity analyses. Restricted cubic splines revealed that an almost linear relationship between SII, PLR and coagulopathy risk and poor prognosis (P for all nonlinearities > 0.05). Finally, receiver operating characteristic (ROC) curves indicated that the SII and PLR had certain diagnostic and predictive values for TBI-related coagulopathy [AUC(SII) = 0.666 (95% CI 0.566– 0.766), AUC(PLR) = 0.752 (95% CI 0.662– 0.842)] and prognosis [AUC(SII) = 0.657 (95% CI 0.548– 0.766), AUC(PLR) = 0.700 (95% CI 0.596– 0.805)]. The stratification of isolated TBI and TBI with multi-trauma does not affect SII and PLR in predicting TBI-related coagulopathy and poor prognosis in the subgroup analysis (P > 0.05).
Conclusion: This study demonstrated that the SII and PLR had a significant correlation with coagulopathy risk and prognosis at 6 months after discharge. SII and PLR were predictive of coagulopathy and poor prognosis, specifically PLR value. It suggests that the SII and PLR might be promising biomarkers for predicting TBI-related coagulopathy and prognosis.
Trial Registration: The study was registered in the ethics committee of the Third Affiliated Hospital of Southern Medical University (2024-ER-005).

Keywords: traumatic brain injury, coagulopathy, inflammation, prognosis, SII, PLR