Factors associated with strain in carers of people with traumatic brain injury.

OBJECTIVE: To explore factors associated with strain in carers of patients with traumatic brain injury. DESIGN: Cross-sectional cohort study. PARTICIPANTS: Forty-eight carers of patients with traumatic brain injury admitted to a neurosurgical unit over a 9-year period were assessed an average of 9.3 years after injury. MEASURES: Caregiver Strain Index (CSI), Neurobehavioral Functioning Inventory (NFI), Glasgow Outcome Scale (GOS), Virginia Prediction Tree Score, and carer and patient demographics. PROCEDURE: Carers were assessed via postal survey for levels of strain using the CSI and for their perception of the patients' disabilities using the NFI. RESULTS: Elevated levels of strain were found in 42% of carers. Using logistic regression, outcome as rated by the patients' general practitioner on the GOS and all subscales of the NFI (except Somatic) explained 41% to 57% of the variance in strain and predicted group membership correctly in 72.9% of cases. No individual variable contributed significantly to the explained variance in the model. CONCLUSION: A number of factors appear to combine to result in feelings of strain, but the GOS could be used as a crude screening tool. Interventions for cognitive, behavioral, and emotional difficulties may be most useful for carers.

Validation of the IMPACT outcome prediction score using the Nottingham Head Injury Register dataset.

BACKGROUND: Comparison of traumatic brain injury (TBI) outcomes is severely limited by the absence of a universally accepted and validated outcome prediction score. The IMPACT group recently reported models predicting mortality and unfavorable outcome after TBI, based on the outcomes of patients with moderate and severe head injury reported in two large clinical trials. METHODS: We have used prospectively collected data from 1,276 adult patients from the Nottingham Head Injury Register admitted to a single UK neurosurgical unit during a 10-year period to validate the IMPACT score models. The two models were validated for discrimination, calibration, and accuracy, using multiple imputation to adjust for missing data. RESULTS: One thousand sixty-one patients (83%) had a complete set of data. For the multiply imputed analysis, the IMPACT prognostic models showed satisfactory discrimination (area under the receiver operator curve for mortality, 0.835; 95% confidence interval, 0.811-0.858; unfavorable outcome, 0.828; 95% confidence interval, 0.805-0.851) and accuracy (Brier Accuracy Score for mortality, 0.403, p < 0.01; unfavorable outcome, 0.371, p < 0.01). Good calibration was evident for unfavorable outcome, but mortality risk was underestimated by the scoring system in our sample (Hosmer-Lemeshow test: mortality: p < 0.01; unfavorable outcome: p = 0.6). These results were not significantly changed when repeated using patients with complete data only. CONCLUSION: The 2005 IMPACT model for unfavorable outcome performs well when used to predict outcome in adults with moderate and severe TBI presenting to a British neurosurgical center. However, the model for mortality fitted less well, slightly overestimating mortality in the higher-risk groups.