Introduction: To date, many prognostic models have been proposed to predict the outcome of patients withtraumatic brain injuries. External validation of these models in different populations is of great importancefor their generalization. The present study was designed, aiming to determine the value of CRASH prognosticmodel in prediction of 14-day mortality (14-DM) and 6-month unfavorable outcome (6-MUO) of patients withtraumatic brain injury. Methods: In the present prospective diagnostic test study, calibration and discriminationof CRASH model were evaluated in head trauma patients referred to the emergency department. Variablesrequired for calculating CRASH expected risks (ER), and observed 14-DM and 6-MUO were gathered. Then ERof 14-DM and 6-MUO were calculated. The patients were followed for 6 months and their 14-DM and 6-MUOwere recorded. Finally, the correlation of CRASH ER and the observed outcome of the patients was evaluated.The data were analyzed using STATA version 11.0. Results: In this study, 323 patients with the mean age of 34.0´s 19.4 years were evaluated (87.3% male). Calibration of the basic and CT models in prediction of 14-day and6-month outcome were in the desirable range (P Ç 0.05). Area under the curve in the basic model for predictionof 14-DM and 6-MUO were 0.92 (95% CI: 0.89–0.96) and 0.92 (95% CI: 0.90–0.95), respectively. In addition,area under the curve in the CT model for prediction of 14-DM and 6-MUO were 0.93 (95% CI: 0.91–0.97) and0.93 (95% CI: 0.91–0.96), respectively. There was no significant difference between the discriminations of thetwo models in prediction of 14-DM (p Æ 0.11) and 6-MUO (p Æ 0.1). Conclusion: The results of the presentstudy showed that CRASH prediction model has proper discrimination and calibration in predicting 14-DMand6-MUO of head trauma patients. Since there was no difference between the values of the basic and CT models,using the basic model is recommended to simplify the risk calculations
