Citation

Walker W, Stromberg KA, Marwitz JH, Sima AP, Agyemang AA, Graham KM, Harrison-Felix CL, Hoffman J, Brown AW, Kreutzer JS, Merchant R. J. Neurotrauma 2018; 35(14): 1587-1595.

Affiliation

Virginia Commonwealth University Department of Physical Medicine and Rehabilitation, 172801, Richmond, Virginia, United States ; randall.merchant@vcuhealth.org.

Copyright

(Copyright © 2018, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2017.5359

PMID

29566600

Abstract

For patients surviving serious traumatic brain injury (TBI), families and other stakeholders often desire information on long-term functional prognosis, but accurate and easy-to-use clinical tools are lacking. We aimed to build utilitarian 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 TBI. Flexible classification tree statistical modeling was used on prospectively collected data from the TBI-Model Systems (TBIMS) inception cohort study. Enrollments occurred at seventeen designated, or previously designated, TBIMS inpatient rehabilitation facilities. Analysis included all participants with non-penetrating TBI injured between Jan 1997 - Jan 2017. Sample sizes were 10,125 (year-1), 8,821 (year-2), and 6,165 (year-5) after cross-sectional exclusions (death, vegetative state, insufficient post-injury time, unavailable outcome). In our final models, posttraumatic 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, premorbid 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% and 10.9% respectively, and the best and worst Severe Disability rates were 3.9% and 64.1%. Predictability in test datasets ranged from C-statistic of 0.691 (year-1; CI: 0.675, 0.711) to 0.731 (year-2; CI: 0.724, 0.738). In conclusion, we developed a clinically useful tool to provide prognostic information on 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.

Language: en

Keywords

ADULT BRAIN INJURY; OUTCOME MEASURES; PROSPECTIVE STUDY; RECOVERY; TRAUMATIC BRAIN INJURY