title: Predicting outcome after traumatic brain injury: practical prognostic models based on large cohort of international patients.
abstract: OBJECTIVE
  To develop and validate practical prognostic models for death at 14 days and for death or severe disability six months after traumatic brain injury.
  
  
  METHODS
  Multivariable logistic regression to select variables that were independently associated with two patient outcomes. Two models designed: "basic" model (demographic and clinical variables only) and "CT" model (basic model plus results of computed tomography). The models were subsequently developed for high and low-middle income countries separately.
  
  
  METHODS
  Medical Research Council (MRC) CRASH Trial.
  
  
  METHODS
  10,008 patients with traumatic brain injury. Models externally validated in a cohort of 8509.
  
  
  RESULTS
  The basic model included four predictors: age, Glasgow coma scale, pupil reactivity, and the presence of major extracranial injury. The CT model also included the presence of petechial haemorrhages, obliteration of the third ventricle or basal cisterns, subarachnoid bleeding, midline shift, and non-evacuated haematoma. In the derivation sample the models showed excellent discrimination (C statistic above 0.80). The models showed good calibration graphically. The Hosmer-Lemeshow test also indicated good calibration, except for the CT model in low-middle income countries. External validation for unfavourable outcome at six months in high income countries showed that basic and CT models had good discrimination (C statistic 0.77 for both models) but poorer calibration.
  
  
  CONCLUSIONS
  Simple prognostic models can be used to obtain valid predictions of relevant outcomes in patients with traumatic brain injury.
authors.affiliation: London School of Hygiene and Tropical Medicine, London WC1B 3DP. Pablo.perel@lshtm.ac.uk
authors.forename: Pablo
authors.initials: P
authors.lastname: Perel
authors.forename: Miguel
authors.initials: M
authors.lastname: Arango
authors.forename: Tim
authors.initials: T
authors.lastname: Clayton
authors.forename: Phil
authors.initials: P
authors.lastname: Edwards
authors.forename: Edward
authors.initials: E
authors.lastname: Komolafe
authors.forename: Stuart
authors.initials: S
authors.lastname: Poccock
authors.forename: Ian
authors.initials: I
authors.lastname: Roberts
authors.forename: Haleema
authors.initials: H
authors.lastname: Shakur
authors.forename: Ewout
authors.initials: E
authors.lastname: Steyerberg
authors.forename: Surakrant
authors.initials: S
authors.lastname: Yutthakasemsunt
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data; D001930:Brain Injuries / Q000000981:diagnostic imaging / Q000401:mortality*; D015331:Cohort Studies; D015600:Glasgow Coma Scale; D006801:Humans; D007182:Income; D015999:Multivariate Analysis; D017063:Outcome Assessment, Health Care / Q000592:standards*; D011379:Prognosis; D014057:Tomography, X-Ray Computed