Accuracy of the mTBI biomarkers, S100B, GFAP and UCH-L1, in the Belgian population

Abstract

Background: New biomarkers provide some insights for the diagnosis of mTBI as some limitations were reported for the CT scan, the gold standard diagnostic tool of mTBI. Still, there is a lack of characterization of those biomarkers leading to uncertainty in their use in clinical practice. Aim(s): Then, the aim of this study is to respond to several questions regarding mTBI biomarkers, particularly the factors that impact the specificity of S100B, GFAP and UCH-L1 but also, the cost-effectiveness of their implementation in routine and the adaptation of their cut-offs. Methods: Firstly, the concentration of GFAP and UCH-L1 was measured in 341 non-suspected mTBI participants of the SarcoPhAge cohort to assess the specificity of the mTBI test and the confounding factors of the biomarkers. Then, using data (2022) of the SIMÉ (CHU de Liège), decision tree models were created to assess if the mTBI test is the most cost-effective scenario for mTBI management compared to sending every patient to the CT scan or using the CCTHR as a rule-out tool for CT scan. Thirdly, the measurement of S100B, GFAP and UCH-L1 was performed in participants from the MiTicBraIn cohort, a multicentric prospective cohort composed of 82 mTBI patients recruited in several Walloon hospitals, to assess the sensitivity of the biomarkers. Analysis: UCH-L1 confounding factors are age, BMI and cystatin C. In addition to the confounding factors of UCH-L1, GFAP concentration is also impacted by sex and MMSE. A maximum mTBI test specificity of 33% was discovered for the SarcoPhAge cohort while the specificity decreased to 10% in participants with cystatin C > 1.55 and to 2.08% in participants from 80 years old. Then, in the younger population the cost-effectiveness of the mTBI test as a rule-out tool was demonstrated while in the older population, the CCTHR is more cost-effective. Yet, in the adult population, the CCTHR scenario costs less than the mTBI test scenario but the mTBI test scenario prevents from more CT scans and hospitalizations, suggesting a moderate cost-effectiveness of the mTBI test scenario. Lastly, the combination of GFAP and S100B performed better as a diagnostic tool of mTBI than the mTBI test and S100B test. Conclusion: Finally, our results are mitigated concerning the implementation of the mTBI test in the clinical practice due to the lack of specificity and a moderate cost-effectiveness of the biomarkers. Still, the new combination of GFAP+S100B provides new insights into the diagnosis of mTBI.

Date of Award	19 Jan 2024
Original language	English
Awarding Institution	University of Namur
Supervisor	Etienne Cavalier (Supervisor) & Aurélie Ladang (Co-Supervisor)