Predicting Outcomes in Patients with Diffuse Axonal Injury: External Validation of the Widely Used Prognostic Instruments.

Aim: Accurate prognosis of diffuse axonal injury (DAI) is important in directing clinical care, allocating resources appropriately, and communicating with families and surrogate decision-makers.

Methods: A study was conducted on patients with clinical DAI due to closed-head traumatic brain injury treated at a trauma center in Brazil from July 2013 to September 2015.  The objective efficacy of the Glasgow Coma Scale (GCS), Trauma and Injury Severity Scoring system (TRISS), New Trauma and Injury Severity Scoring system (NTRISS), Abbreviated Injury Scale (AIS)/head, Corticosteroid Randomization After Significant Head Injury (CRASH), and International Mission on Prognosis and Analysis of Clinical Trials (IMPACT) models in the prediction of mortality at 14 days and 6-months and unfavorable outcomes at 6 months was tested.

Results: Our cohort comprised 95 prospectively recruited adults (85 males, 10 females, mean age 30.3 ± 10.9 years) admitted with DAI. Model efficacy was assessed through discrimination (area under the curve [AUC]), and Cox calibration. The AIS/head, TRISS, NTRISS, CRASH, and IMPACT models were able to discriminate both mortality and unfavorable outcomes (AUC 0.78-0.87). IMPACT models resulted in a statistically perfect calibration for both 6-month outcome variables; mortality and 6-month unfavorable outcome. Calibration also revealed that TRISS, NTRISS, and CRASH systematically overpredicted both outcomes, except for 6-month unfavorable outcome with TRISS.

Conclusions: The results of this study suggest that TRISS, NTRISS, CRASH, and IMPACT models satisfactorily discriminate between mortality and unfavorable outcomes. However, only the TRISS and IMPACT models showed accurate calibration when predicting 6-month unfavorable outcome.