Global Disability Trajectories Over the First Decade Following Combat Concussion.

OBJECTIVE: To examine global disability trajectories in US military with and without traumatic brain injury (TBI) over the first decade following deployment to identify risk profiles for better intervention stratification, hopefully reducing long-term cost. SETTING: Patients and participants were enrolled in combat or directly following medical evacuation at the time of injury and followed up every 6 months for 10 years. PARTICIPANTS: There are 4 main groups (n = 475), 2 primary and 2 exploratory: (1) combat-deployed controls without a history of blast exposure "non-blast- control" (n = 143), (2) concussive blast TBI "'blast-TBI" (n = 236) (primary), (3) combat-deployed controls with a history of blast exposure "blast-control" (n = 54), and (4) patients sustaining a combat concussion not from blast "non-blast-TBI" (n = 42) (exploratory). DESIGN: Prospective, observational, longitudinal study. MAIN MEASURES: Combat concussion, blast exposure, and subsequent head injury exposure over the first decade post-deployment. Global disability measured by the Glasgow Outcome Scale Extended (GOSE). RESULTS: Latent class growth analysis identified 4 main trajectories of global outcome, with service members sustaining combat concussion 37 to 49 times more likely to be in the worse disability trajectories than non-blast-controls (blast-TBI: odds ratio [OR] = 49.33; CI, 19.77-123.11; P < .001; non-blast-TBI: OR = 37.50; CI, 10.01-140.50; P < .001). Even blast-exposed-controls were 5 times more likely to be in these worse disability categories compared with non-blast-controls (OR = 5.00; CI, 1.59-15.99; P = .007). Adjustment for demographic factors and subsequent head injury exposure did not substantially alter these odds ratios. CONCLUSIONS: Very high odds of poor long-term outcome trajectory were identified for those who sustained a concussion in combat, were younger at the time of injury, had lower education, and enlisted in the Army above the risk of deployment alone. These findings help identify a risk profile that could be used to target early intervention and screen for poor long-term outcome to aid in reducing the high public health cost and enhance the long-term quality of life for these service members following deployment.