Correlation of Serum S100B with the Severity and Outcome of Traumatic Brain Injury: A Cohort Study

Abstract

Background: The contribution of blood biomarkers and clinical indices following traumatic brain injury (TBI) may provide diagnostic and predictive tools. S100b is one of the extensively studied blood biomarkers of TBI but has led to inconclusive reports of its contribution to discriminating the severity and outcomes of injury. This investigation seeks to verify S100B concentrations in blood as severity and outcome predictors of TBI.

Methods: Eighty-five patients sustaining TBI (Glasgow Coma Scale score [GCS] 3-15) getting admitted to the neurosurgery department were included in the study. Serum was collected within 48 hours of trauma and was analysed for S100B concentration. Demographic details of patients were collected, along with data on injury mechanisms, CT brain findings, and GCS. The outcome was assessed using the Glasgow Outcome Scale Extended (dichotomised in unfavourable vs favourable and death vs alive), 3- and 6-months post-injury.

Results: On admission, serum level of S100B was significantly different in mild, moderate and severe TBI groups (p=0.000). However, the post hoc test confirmed a significant difference in the protein concentration between mild vs severe (p=0.000) and moderate vs severe (p=0.004) TBI. S100B concentrations collected on admission were able to efficiently differentiate between favourable and unfavourable groups at three months follow-ups (p=0.000).  Median serum levels were significantly higher among deaths. The protein inversely correlated with GCS on admission, and the GOS E outcome scores at 3 and 6 months dichotomised as favourable (GOS E5-8) and unfavourable (GOS E 1-4) outcomes. A positive correlation was observed with total scores of Rotterdam CT Brain categorisation (ρ= 0.289, p=0.005). S100B showed a moderate discriminative ability with the sensitivity of 72%, 71%, 72% and 74% in severity, mortality, and three- and six-months poor outcome prediction, respectively.

Conclusion:  Including on-admission S100B in the investigation panel for TBI may aid as an extra reliable tool to predict patient outcomes and strategies for treatment accordingly.