title: Glial Fibrillary Acidic Protein and Ubiquitin C-Terminal Hydrolase-L1 as Outcome Predictors in Traumatic Brain Injury.
abstract: OBJECTIVE
  Biomarkers ubiquitin C-terminal hydrolase-L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) may help detect brain injury, assess its severity, and improve outcome prediction. This study aimed to evaluate the prognostic value of these biomarkers during the first days after brain injury.
  
  
  METHODS
  Serum UCH-L1 and GFAP were measured in 324 patients with traumatic brain injury (TBI) enrolled in a prospective study. The outcome was assessed using the Glasgow Outcome Scale (GOS) or the extended version, Glasgow Outcome Scale-Extended (GOSE).
  
  
  RESULTS
  Patients with full recovery had lower UCH-L1 concentrations on the second day and patients with favorable outcome had lower UCH-L1 concentrations during the first 2 days compared with patients with incomplete recovery and unfavorable outcome. Patients with full recovery and favorable outcome had significantly lower GFAP concentrations in the first 2 days than patients with incomplete recovery or unfavorable outcome. There was a strong negative correlation between outcome and UCH-L1 in the first 3 days and GFAP levels in the first 2 days. On arrival, both UCH-L1 and GFAP distinguished patients with GOS score 1-3 from patients with GOS score 4-5, but not patients with GOSE score 8 from patients with GOSE score 1-7. For UCH-L1 and GFAP to predict unfavorable outcome (GOS score ≤ 3), the area under the receiver operating characteristic curve was 0.727, and 0.723, respectively. Neither UCHL-1 nor GFAP was independently able to predict the outcome when age, worst Glasgow Coma Scale score, pupil reactivity, Injury Severity Score, and Marshall score were added into the multivariate logistic regression model.
  
  
  CONCLUSIONS
  GFAP and UCH-L1 are significantly associated with outcome, but they do not add predictive power to commonly used prognostic variables in a population of patients with TBI of varying severities.
authors.affiliation: Perioperative Services, Intensive Care Medicine and Pain Management, Turku University Hospital and University of Turku, Turku, Finland. Electronic address: riikka.takala@gmail.com.
authors.forename: Riikka S K
authors.initials: RS
authors.lastname: Takala
authors.affiliation: Division of Clinical Neurosciences, Department of Neurosurgery, Turku University Hospital and University of Turku, Turku, Finland; Division of Clinical Neurosciences, Department of Rehabilitation and Brain Trauma, Turku University Hospital and University of Turku, Turku, Finland; Department of Neurology, University of Turku, Turku, Finland.
authors.forename: Jussi P
authors.initials: JP
authors.lastname: Posti
authors.affiliation: Systems Medicine, VTT Technical Research Centre of Finland, Tampere, Finland.
authors.forename: Hilkka
authors.initials: H
authors.lastname: Runtti
authors.affiliation: Division of Anaesthesia, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: Virginia F
authors.initials: VF
authors.lastname: Newcombe
authors.affiliation: Division of Anaesthesia, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: Joanne
authors.initials: J
authors.lastname: Outtrim
authors.affiliation: Perioperative Services, Intensive Care Medicine and Pain Management, Turku University Hospital and University of Turku, Turku, Finland.
authors.forename: Ari J
authors.initials: AJ
authors.lastname: Katila
authors.affiliation: Division of Clinical Neurosciences, Department of Neurosurgery, Turku University Hospital and University of Turku, Turku, Finland; Division of Clinical Neurosciences, Department of Rehabilitation and Brain Trauma, Turku University Hospital and University of Turku, Turku, Finland.
authors.forename: Janek
authors.initials: J
authors.lastname: Frantzén
authors.affiliation: Department of Neurology, University of Turku, Turku, Finland.
authors.forename: Henna
authors.initials: H
authors.lastname: Ala-Seppälä
authors.affiliation: Department of Neurology, University of Turku, Turku, Finland.
authors.forename: Anna
authors.initials: A
authors.lastname: Kyllönen
authors.affiliation: Department of Neurology, University of Turku, Turku, Finland.
authors.forename: Henna-Riikka
authors.initials: HR
authors.lastname: Maanpää
authors.affiliation: Department of Neurology, University of Turku, Turku, Finland.
authors.forename: Jussi
authors.initials: J
authors.lastname: Tallus
authors.affiliation: Department of Neurology, University of Turku, Turku, Finland.
authors.forename: Md Iftakher
authors.initials: MI
authors.lastname: Hossain
authors.affiliation: Division of Anaesthesia, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Coles
authors.affiliation: Department of Clinical Neurosciences, Neurosurgery Unit, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Hutchinson
authors.affiliation: Systems Medicine, VTT Technical Research Centre of Finland, Tampere, Finland.
authors.forename: Mark
authors.initials: M
authors.lastname: van Gils
authors.affiliation: Division of Anaesthesia, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: David K
authors.initials: DK
authors.lastname: Menon
authors.affiliation: Division of Clinical Neurosciences, Department of Rehabilitation and Brain Trauma, Turku University Hospital and University of Turku, Turku, Finland; Department of Neurology, University of Turku, Turku, Finland.
authors.forename: Olli
authors.initials: O
authors.lastname: Tenovuo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D001930:Brain Injuries / Q000097:blood* / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D015600:Glasgow Coma Scale; D005904:Glial Fibrillary Acidic Protein / Q000097:blood*; D006801:Humans; D015601:Injury Severity Score; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D043222:Ubiquitin Thiolesterase / Q000097:blood*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D005904:Glial Fibrillary Acidic Protein; C482860:UCHL1 protein, human; D043222:Ubiquitin Thiolesterase
keywords: Biomarkers; GFAP; Outcome; Traumatic brain injury; UCH-L1