Predicting outcome after traumatic brain injury: practical prognostic models based on large cohort of international patients.
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.
London School of Hygiene and Tropical Medicine, London WC1B 3DP. Pablo.perel@lshtm.ac.uk
Perel
Pablo
P
Arango
Miguel
M
Clayton
Tim
T
Edwards
Phil
P
Komolafe
Edward
E
Poccock
Stuart
S
Roberts
Ian
I
Shakur
Haleema
H
Steyerberg
Ewout
E
Yutthakasemsunt
Surakrant
S
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