Health Phenotypes and Neurobehavioral Symptom Severity among Post-9/11 Veterans with Mild Traumatic Brain Injury: A Chronic Effects of Neurotrauma Consortium Study

Objective: To evaluate whether neurobehavioral symptoms differ between groups of veterans with mild traumatic brain injury (mTBI) classified by health characteristics. Participants: A total of 71 934 post-9/11 veterans with mTBI from the Chronic Effects of Neurotrauma Consortium Epidemiology warfighter cohort. Design: Cross-sectional analysis of retrospective cohort. Main Measures: Health phenotypes identified using latent class analysis of health and function over 5 years. Symptom severity measured using Neurobehavioral Symptom Inventory; domains included vestibular, somatic, cognitive, and affective. Results: Veterans classified as moderately healthy had the lowest symptom burden while the polytrauma phenotype group had the highest. After accounting for sociodemographic and injury characteristics, polytrauma phenotype veterans had about 3 times the odds of reporting severe symptoms in each domain compared with moderately healthy veterans. Those veterans who were initially moderately healthy but whose health declined over time had about twice the odds of severe symptoms as consistently healthier Veterans. The strongest associations were in the affective domain. Compared with the moderately healthy group, veterans in other phenotypes were more likely to report symptoms substantially interfered with their daily lives (odds ratio range: 1.3-2.8). Conclusion: Symptom severity and interference varied by phenotype, including between veterans with stable and declining health. Ameliorating severe symptoms, particularly in the affective domain, could improve health trajectories following mTBI.