Predicting long-term global outcome after traumatic brain injury: Development of a practical prognostic tool using the traumatic brain injury model systems national database
Study developed decision trees from commonly collected clinical variables to predict Glasgow Outcome Scale (GOS) functional levels at 1, 2, and 5 years after moderate-to-severe closed traumatic brain injury (TBI). Flexible classification tree statistical modeling was used on prospectively collected data from the TBI-Model Systems (TBIMS) inception cohort study. Enrollments occurred at 17 designated, or previously designated, TBIMS inpatient rehabilitation facilities. Analysis included all participants with non-penetrating TBI injured between January 1997 and January 2017. Sample sizes were 10,125 (year 1); 8,821 (year 2), and 6,165 (year 5) patientsafter cross-sectional exclusions (death, vegetative state, insufficient post-injury time, and unavailable outcome). In the final models, post-traumatic amnesia (PTA) duration consistently dominated branching hierarchy and was the lone injury characteristic significantly contributing to GOS predictability. Lower-order variables that added predictability were age, pre-morbid education, productivity, and occupational category. Generally, patient outcomes improved with shorter PTA, younger age, greater pre-morbid productivity, and higher pre-morbid vocational or educational achievement. Across all prognostic groups, the best and worst good recovery rates were 65.7 percent and 10.9 percent, respectively, and the best and worst severe disability rates were 3.9 percent and 64.1 percent, respectively. Predictability in test data sets ranged from a C-statistic of 0.691 (year 1) to 0.731 (year 2). This study developed a clinically useful tool to predit long-term functional outcomes for adult survivors of moderate and severe closed TBI. Predictive accuracy for GOS level was demonstrated in an independent test sample. Length of PTA, a clinical marker of injury severity, was by far the most critical outcome determinant.
Author(s):
Walker, William C.|Stromberg, Katharine A.|Marwitz, Jennifer H.|Sima, Adam P.|Agyemang, Amma A.|Graham, Kristin M.|Harrison-Felix, Cynthia |Hoffman, Jeanne M.|Brown, Allen W.|Kreutzer, Jeffrey S>|Merchant, Randall|
