Prediction of global functional outcome and post-concussive symptoms following mild traumatic brain injury: external validation of prognostic models in the CENTER-TBI study
Journal of Neurotrauma
The majority of patients with traumatic brain injury (TBI) are categorized as mild according to a baseline Glasgow Coma Scale (GCS) score of 13 to 15. Prognostic models that were developed to predict functional outcome and persistent post-concussive symptoms (PPCS) after mild TBI have rarely been externally validated. We aimed to identify validate existing models predicting 3 to 12-month Glasgow Outcome Scale Extended (GOSE) or PPCS in adults with mild TBI. We analyzed data from the
... rom the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) project, which included 2862 adults with mild TBI, with 6-month GOSE available for 2374, and the Rivermead Post-concussion Symptom Questionnaire (RPQ) for 1605 participants. Model performance was evaluated based on calibration (graphically and characterized by slope and intercept) and discrimination (c-index). We validated five published models for 6-month GOSE and three for 6-month PPCS scores. The models used different cutoffs for outcome and some included symptoms measured 2 weeks post-injury. Discriminative ability varied substantially (C- index between 0.58 and 0.79). The models developed in the CRASH trial for prediction of GOSE<5 discriminated best (C- index 0.78 and 0.79), but were poorly calibrated. The best performing models for PPCS included 2-week symptoms (C- index 0.75 and 0.76). In conclusion, none of the prognostic models for early prediction of GOSE and PPCS has both good calibration and discrimination in persons with mild TBI. In future studies prognostic models should be tailored to the population of mild TBI, predicting relevant endpoints based on readily available predictors. Key words: external validation, mild traumatic brain injury, prognostic model, Glasgow Outcome Scale Extended, post-concussive symptoms.