title: Prediction of outcome after moderate and severe traumatic brain injury: external validation of the International Mission on Prognosis and Analysis of Clinical Trials (IMPACT) and Corticoid Randomisation After Significant Head injury (CRASH) prognostic models.
abstract: OBJECTIVE
  The International Mission on Prognosis and Analysis of Clinical Trials and Corticoid Randomisation After Significant Head injury prognostic models predict outcome after traumatic brain injury but have not been compared in large datasets. The objective of this is study is to validate externally and compare the International Mission on Prognosis and Analysis of Clinical Trials and Corticoid Randomisation after Significant Head injury prognostic models for prediction of outcome after moderate or severe traumatic brain injury.
  
  
  METHODS
  External validation study.
  
  
  METHODS
  We considered five new datasets with a total of 9,036 patients, comprising three randomized trials and two observational series, containing prospectively collected individual traumatic brain injury patient data.
  
  
  RESULTS
  Outcomes were mortality and unfavorable outcome, based on the Glasgow Outcome Score at 6 months after injury. To assess performance, we studied the discrimination of the models (by area under the receiver operating characteristic curves), and calibration (by comparison of the mean observed to predicted outcomes and calibration slopes). The highest discrimination was found in the Trauma Audit and Research Network trauma registry (area under the receiver operating characteristic curves between 0.83 and 0.87), and the lowest discrimination in the Pharmos trial (area under the receiver operating characteristic curves between 0.65 and 0.71). Although differences in predictor effects between development and validation populations were found (calibration slopes varying between 0.58 and 1.53), the differences in discrimination were largely explained by differences in case mix in the validation studies. Calibration was good, the fraction of observed outcomes generally agreed well with the mean predicted outcome. No meaningful differences were noted in performance between the International Mission on Prognosis and Analysis of Clinical Trials and Corticoid Randomisation After Significant Head injury models. More complex models discriminated slightly better than simpler variants.
  
  
  CONCLUSIONS
  Since both the International Mission on Prognosis and Analysis of Clinical Trials and the Corticoid Randomisation After Significant Head injury prognostic models show good generalizability to more recent data, they are valid instruments to quantify prognosis in traumatic brain injury.
authors.affiliation: Department of Public Health, Center for Medical Decision Making, Erasmus MC, Rotterdam, The Netherlands. b.roozenbeek@erasmusmc.nl
authors.forename: Bob
authors.initials: B
authors.lastname: Roozenbeek
authors.forename: Hester F
authors.initials: HF
authors.lastname: Lingsma
authors.forename: Fiona E
authors.initials: FE
authors.lastname: Lecky
authors.forename: Juan
authors.initials: J
authors.lastname: Lu
authors.forename: James
authors.initials: J
authors.lastname: Weir
authors.forename: Isabella
authors.initials: I
authors.lastname: Butcher
authors.forename: Gillian S
authors.initials: GS
authors.lastname: McHugh
authors.forename: Gordon D
authors.initials: GD
authors.lastname: Murray
authors.forename: Pablo
authors.initials: P
authors.lastname: Perel
authors.forename: Andrew I
authors.initials: AI
authors.lastname: Maas
authors.forename: Ewout W
authors.initials: EW
authors.lastname: Steyerberg
mesh_terms: D001057:Apolipoproteins E / Q000235:genetics; D001930:Brain Injuries / Q000175:diagnosis* / Q000188:drug therapy / Q000401:mortality / Q000628:therapy; D013759:Dronabinol / Q000031:analogs & derivatives / Q000627:therapeutic use; D023261:Glasgow Outcome Scale; D006146:Guanidines / Q000627:therapeutic use; D006801:Humans; D007036:Hypothermia, Induced; D016015:Logistic Models; D015233:Models, Statistical; D018696:Neuroprotective Agents / Q000627:therapeutic use; D011379:Prognosis; D012372:ROC Curve; D012042:Registries
chemical_list: D001057:Apolipoproteins E; D006146:Guanidines; D018696:Neuroprotective Agents; C079779:aptiganel; D013759:Dronabinol; C062018:HU 211