The prognostic significance of biomarkers in cerebrospinal fluid following severe traumatic brain injury: a systematic review and meta-analysis

After severe traumatic brain injury (sTBI) proteins, neurotrophic factors and inflammatory markers are released into the biofluids. This review and meta-analysis searched the literature for prognostic candidate cerebrospinal fluid markers and their relation to sTBI patient outcome. A systematic search of the literature was carried out across PubMed, EMBASE, PubMed Central (PMC), and Cochrane Central Library. Biomarker concentrations were related to the Glasgow Outcome Scale dichotomized into favorable and unfavorable outcomes. When a biomarker was reported in ≥ 3 studies, it was included in meta-analysis. The search returned 1527 articles. After full-text analysis, 54 articles were included, 34 from the search, and 20 from the reference lists. Of 9 biomarkers, 8 were significantly different compared to controls (IL-4, IL-6, IL-8, IL-10, TNFα, sFas, BDNF, and cortisol). Of these, 5 were significantly increased in sTBI patients with unfavorable outcome (IL-6, IL-8, IL-10, TNFα, and cortisol), compared to patients with favorable outcome. This review demonstrated a correlation between 5 biomarkers and clinical outcome in sTBI patients. The paucity of included studies, however, makes it difficult to extrapolate further on this finding.