Background: Trauma centers routinely benchmark their survival outcomes against a national norm using the TRISS methodology. However, the use of survival as a measure of the effectiveness of trauma care may be too limited in scope because it fails to capture information regarding functional outcomes.
Methods: The objective of this study was to develop a prediction model that allows hospitals to benchmark their functional outcomes in blunt trauma patients, and to determine whether the assessment of hospital "quality" depends on the choice of outcome measure: survival or survival combined with functional outcome. This retrospective cohort study was based on patients, aged 18 years or older, in the National Trauma Database who sustained blunt trauma in 1999 without associated head or spinal cord injury. We developed a sequential logistic model to predict the probability of a good functional outcome. The TRISS methodology was customized to this data set to obtain a survival model. Using each of these prediction models, we then obtained two standardized measures of hospital performance: one based on the number of survivors and the other based on the number of survivors with good functional outcomes. These standardized outcome measures were then used to identify low-performance and high-performance hospitals. The ranking based on these two different measures were compared.
Results: Fifteen of the 27 hospitals in the study cohort were categorized differently when their performance was benchmarked using survival versus functional outcome. Kappa analysis revealed minimal agreement between these two quality measures on the identity of hospital quality outliers (kappa = 0.04; p = 0.35).
Conclusion: The evaluation of hospital quality depends on whether hospital performance is judged by looking at survival or at survival combined with functional outcome. Because functional status is an important outcome of major concern to survivors, it is important to include it in hospital performance assessment. Consideration should be given to including functional outcome in the evaluation of trauma center performance.