title: External validation of the international mission for prognosis and analysis of clinical trials model and the role of markers of coagulation.
abstract: BACKGROUND
  Markers of coagulation have shown to have important value in predicting traumatic brain injury outcome.
  
  
  OBJECTIVE
  To externally validate and investigate the role of markers of coagulation for outcome prediction by using the International Mission for Prognosis and Analysis of Clinical Trials (IMPACT) model while adjusting for overall injury severity.
  
  
  METHODS
  A retrospective chart analysis of traumatic brain injury patients admitted to Helsinki University Central Hospital between 2009 and 2010 was performed. Outcome was estimated by using the criteria of the IMPACT model. Admission international normalized ratio (INR) and platelet count were used as markers of coagulation. Overall injury severity was categorized with the injury severity score (ISS). Variables were added to the calculated IMPACT risk, generating new models. Model performance was assessed by analyzing and comparing the area under the curve (AUC) of the models.
  
  
  RESULTS
  For 342 included patients, 6-month mortality was 32% and unfavorable neurological outcome was 36%. Patients with a poor outcome had lower platelets and higher INR and ISS than those with good outcome (P < .001). The IMPACT model had an AUC of 0.85 for predicting mortality and 0.81 for neurological outcome. Addition of INR but not ISS or platelets to the IMPACT predicted risk improved the predictive validity for mortality ([INCREMENT]AUC 0.02, P = .034) but not neurological outcome ([INCREMENT]AUC 0.00, P = .401). In multivariate analysis, INR remained significant for mortality but not for neurological outcome when adjusting for IMPACT risk and ISS (P = .012).
  
  
  CONCLUSIONS
  The IMPACT model showed excellent performance, and INR was an independent predictor for mortality, independent of overall injury severity.
authors.affiliation: *Department of Neurosurgery, Helsinki University Central Hospital, Helsinki, Finland; ‡Department of Anaesthesiology and Intensive Care Medicine, Helsinki University Central Hospital, Helsinki, Finland; §Department of Orthopedics and Traumatology, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Rahul
authors.initials: R
authors.lastname: Raj
authors.forename: Jari
authors.initials: J
authors.lastname: Siironen
authors.forename: Riku
authors.initials: R
authors.lastname: Kivisaari
authors.forename: Juha
authors.initials: J
authors.lastname: Hernesniemi
authors.forename: Päivi
authors.initials: P
authors.lastname: Tanskanen
authors.forename: Lauri
authors.initials: L
authors.lastname: Handolin
authors.forename: Markus B
authors.initials: MB
authors.lastname: Skrifvars
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood*; D001777:Blood Coagulation; D001930:Brain Injuries / Q000097:blood* / Q000401:mortality*; D005260:Female; D023261:Glasgow Outcome Scale; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D011237:Predictive Value of Tests; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies
chemical_list: D015415:Biomarkers