Long-term physical and mental health outcomes associated with traumatic brain injury severity in post-9/11 veterans: A retrospective cohort study

Evaluation of clinical outcomes and employment status in veterans with dual diagnosis of traumatic brain injury and spinal cord injury

PURPOSE

To examine clinical outcomes and employment status in Veterans with and without a dual diagnosis of traumatic brain injury (TBI) and spinal cord injury (SCI).

METHODS

This cross-sectional study examined a national sample of Veterans enrolled in the VA Million Veteran Program who completed the Comprehensive TBI Evaluation (CTBIE) as part of the Veterans Health Administration's TBI Screening and Evaluation Program. Veterans (N = 12,985) were classified into the following TBI/SCI groups using CTBIE data: those with a dual diagnosis of TBI and SCI (TBI+/SCI+); those with a history of TBI but no SCI (TBI+/SCI-); and those with no history of TBI or SCI (TBI-/SCI-; i.e., the control group). CTBIE-derived outcomes included neurobehavioral symptoms, comorbid psychiatric symptoms, pain and pain interference, and employment status.

RESULTS

Chi-square analyses showed significant associations between TBI/SCI group and all clinical outcomes evaluated (all p's < .001; V = 0.07-0.11). In general, the TBI+/SCI+ and TBI +/SCI- groups endorsed comparable levels of neurobehavioral symptoms, psychiatric symptoms, and pain, but significantly greater rates of symptoms and pain relative to the TBI-/SCI- group. Effect sizes for all pairwise comparisons were small (φ = 0.01-0.11). Finally, there was no significant association between TBI/SCI group and employment status (p = .170; V = 0.02), with all three groups showing relatively comparable rates of unemployment.

CONCLUSIONS

Regardless of SCI status, Veterans with TBI history endorsed poorer clinical outcomes than Veterans without TBI and SCI. However, rates of unemployment were similarly high across all three groups. Findings suggest that any Veteran completing the CTBIE may be at risk for poor clinical and employment outcomes.

Comorbidity and polypharmacy impact neurobehavioral symptoms and symptom validity failure among post-9/11 veterans with mild traumatic brain injury

Objective

The study aimed to examine the association between post-concussive comorbidity burdens [post-traumatic stress disorder (PTSD), depression, and/or headache] and central nervous system (CNS) polypharmacy (five or more concurrent medications) with reported neurobehavioral symptoms and symptom validity screening among post-9/11 veterans with a history of mild traumatic brain injury (mTBI).

Setting

Administrative medical record data from the Department of Veterans Affairs (VA) were used in the study.

Participants

Post-9/11 veterans with mTBI and at least 2 years of VA care between 2001 and 2019 who had completed the comprehensive traumatic brain injury evaluation (CTBIE) were included in the study.

Design

Retrospective cross-sectional design was used in the study.

Main measures

Neurobehavioral Symptom Inventory (NSI), International Classification of Diseases, Ninth Revision, and Clinical Modification diagnosis codes were included in the study.

Results

Of the 92,495 veterans with a history of TBI, 90% had diagnoses of at least one identified comorbidity (PTSD, depression, and/or headache) and 28% had evidence of CNS polypharmacy. Neurobehavioral symptom reporting and symptom validity failure was associated with comorbidity burden and polypharmacy after adjusting for sociodemographic characteristics. Veterans with concurrent diagnoses of PTSD, depression, and headache were more than six times more likely [Adjusted odds ratio = 6.55 (99% CI: 5.41, 7.92)]. to fail the embedded symptom validity measure (Validity-10) in the NSI.

Conclusion

TBI-related multimorbidity and CNS polypharmacy had the strongest association with neurobehavioral symptom distress, even after accounting for injury and sociodemographic characteristics. Given the regular use of the NSI in clinical and research settings, these findings emphasize the need for comprehensive neuropsychological evaluation for individuals who screen positively for potential symptom overreporting, the importance of multidisciplinary rehabilitation to restore functioning following mTBI, and the conscientious utilization of symptom validity measures in research efforts.

Time from injury and age interact in relationship with perceived quality of life outcomes following vocation-focused neuropsychological rehabilitation

At the group level, community-based neuropsychological rehabilitation interventions with a vocational focus are generally effective among individuals with brain injuries. However, individual participants vary significantly in the extent of their improvement, prompting attempts to elucidate individual, injury-related, and environmental factors affecting prognosis. In this study, we examined the relationships between one such factor - "time from injury" (the time between injury and intervention) - and two outcome measures: employment status and perceived quality of life (PQoL), in 157 brain injury survivors, before and after a holistic neuropsychological vocational rehabilitation program. We also examined whether relationships between the variables were moderated by age at onset of treatment and injury severity. In the entire sample, both the proportion of employed participants and average PQoL increased following program participation. Neither, time from injury, severity, nor age at onset of treatment predicted the increase in employment proportion, and severity was not a significant predictor of PQoL. However, an interactive effect indicated that when treatment was started at a younger age, longer time from injury predicted higher levels of PQoL, but when treatment was started at older ages, longer time from injury predicted lower levels of PQoL. When interpreted alongside existing literature, these results suggest that delaying vocational components of rehabilitation can be beneficial for younger participants, while the effectiveness of vocational rehabilitation can be maximized by starting as early as possible among older participants. Most importantly, regardless of age, it appears that vocational rehabilitation can be effective even when initiated many years after injury.

The psychosocial burden of visible disfigurement following traumatic injury

Hundreds of thousands of individuals experience traumatic injuries each year. Some are mild to moderate in nature and patients experience full functional recovery and little change to their physical appearance. Others result in enduring, if not permanent, changes in physical functioning and appearance. Reconstructive plastic surgical procedures are viable treatments options for many patients who have experienced the spectrum of traumatic injuries. The goal of these procedures is to restore physical functioning and reduce the psychosocial burden of living with an appearance that may be viewed negatively by the patient or by others. Even after receipt of reconstructive procedures, many patients are left with residual disfigurement. In some, disability and disfigurement may be so profound that individuals are candidates for vascularized composite allotransplantation (VCA) procedures, i.e., the transplantation of a vascularized human body part containing multiple tissue types (skin, muscle, bone, nerves, and blood vessels) as an anatomical and/or structural unit. This narrative review paper summarizes the literature on the psychosocial burden experienced by those who have visible disfigurement. While many of these individuals experience stigma and discrimination, relatively few studies have employed a stigma framework to understand the psychosocial sequelea. This paper briefly addresses this framework. Last, particular focus is given to the psychosocial issues of individuals with particularly severe injuries who are potential candidates for VCA procedures.

Subjective cognitive and psychiatric well-being in U.S. Military Veterans screened for deployment-related traumatic brain injury: A Million Veteran Program Study

The purpose of this study was to examine subjective cognitive and psychiatric functioning in post-deployed military Veterans who underwent the Veterans Health Administration's Traumatic Brain Injury (TBI) Screening and Evaluation Program and enrolled in the VA's Million Veteran Program (MVP). Veterans (N = 7483) were classified into three groups based on outcomes from the TBI Screening and Evaluation Program: (1) negative TBI screen ('Screen-'), (2) positive TBI screen but no TBI diagnosis ('Screen+/TBI-'), or (3) positive TBI screen and TBI diagnosis ('Screen+/TBI+'). Chi-square analyses revealed significant group differences across all self-reported cognitive and psychiatric health conditions (e.g., memory loss, depression), and ANCOVAs similarly showed a significant association between group and subjective symptom reporting. Specifically, the relationship between TBI group and clinical outcome (i.e., health conditions and symptoms) was such that the Screen+/TBI+ group fared the worst, followed by the Screen+/TBI- group, and finally the Screen- group. However, evaluation of effect sizes suggested that Veterans in the two Screen+ groups (Screen+/TBI+ and Screen+/TBI-) are faring similarly to one another on subjective cognitive and psychiatric functioning, but that both Screen+ groups are faring significantly worse than the Screen- group. Our results have meaningful clinical implications and suggest that Veterans who screen positive for TBI, regardless of ultimate TBI diagnosis, be eligible for similar clinical services so that both groups can benefit from valuable treatments and therapeutics. Finally, this research sets the stage for follow-up work to be conducted within MVP that will address the neurobiological underpinnings of cognitive and psychiatric distress in this population.

Clinical research findings from the long-term impact of military-relevant brain injury consortium-Chronic Effects of Neurotrauma Consortium (LIMBIC-CENC) 2013-2021

This is a summary of the published research from the 14 observational, longitudinal and big-data, epidemiological studies supported by the LIMBIC-CENC program from 2013-2021 examining the long-term effects of combat-related traumatic brain injury (TBI). Findings from these 43 primary and secondary analyses include: 1) unique fluid, advanced neuroimaging and electrophysiologic biomarkers associated with mild traumatic brain injury (mTBI), number of mTBIs and related dysfunction, 2) increases in a range of chronic difficulties, including neurosensory, sleep, pain, cognitive deficits, behavioral disorders, overall symptom burden, healthcare costs and service-connected disability, associated with mTBI, all-severity traumatic brain injury (TBI), blast exposure, and number of mTBIs, and 3) increases in the risk for suicide and neurodegeneration, including dementia and Parkinson's disease, associated with mTBI and all-severity TBI. Ongoing LIMBIC-CENC longitudinal and epidemiologic research will clarify, confirm and expand upon these findings.

The Military Injuries: Understanding Post-Traumatic Epilepsy Study: Understanding Relationships among Lifetime Traumatic Brain Injury History, Epilepsy, and Quality of Life

Understanding risk for epilepsy among persons who sustain a mild (mTBI) traumatic brain injury (TBI) is crucial for effective intervention and prevention. However, mTBI is frequently undocumented or poorly documented in health records. Further, health records are non-continuous, such as when persons move through health systems (e.g., from Department of Defense to Veterans Affairs [VA] or between jobs in the civilian sector), making population-based assessments of this relationship challenging. Here, we introduce the MINUTE (Military INjuries-Understanding post-Traumatic Epilepsy) study, which integrates data from the Veterans Health Administration with self-report survey data for post-9/11 veterans (n = 2603) with histories of TBI, epilepsy and controls without a history of TBI or epilepsy. This article describes the MINUTE study design, implementation, hypotheses, and initial results across four groups of interest for neurotrauma: 1) control; 2) epilepsy; 3) TBI; and 4) post-traumatic epilepsy (PTE). Using combined survey and health record data, we test hypotheses examining lifetime history of TBI and the differential impacts of TBI, epilepsy, and PTE on quality of life. The MINUTE study revealed high rates of undocumented lifetime TBIs among veterans with epilepsy who had no evidence of TBI in VA medical records. Further, worse physical functioning and health-related quality of life were found for persons with epilepsy + TBI compared to those with either epilepsy or TBI alone. This effect was not fully explained by TBI severity. These insights provide valuable opportunities to optimize the resilience, delivery of health services, and community reintegration of veterans with TBI and complex comorbidity.

Prospective Evaluation of Health Outcomes in a Nationwide Sample of Aeromedical Evacuation Casualties: Methods From a Pilot Study

INTRODUCTION

Although retrospective analyses have found that combat-injured service members are at high risk for mental and physical health outcomes following injury, relatively little is known about the long-term health of injured service members. To better understand long-term health outcomes after combat injury, a large, prospective observational cohort collecting both subjective and objective health data is needed. Given that a study of this nature would be costly and face many logistical challenges, we first conducted a pilot to assess the feasibility of a larger, definitive study.

MATERIALS AND METHODS

We ran a prospective, observational pilot study of 119 combat-injured service members and veterans who completed (1) at least one set of laboratory measurements (blood and urine sample collection and vitals measurements) at Clinical Laboratory Improvement Amendment of 1988 compliant laboratory locations and (2) at least one online assessment for the Wounded Warrior Recovery Project (WWRP), a 15-year examination of patient-reported outcomes among service members injured on combat deployment. We recruited the pilot study cohort from WWRP participants who met eligibility criteria and indicated interest in additional research opportunities. We collected laboratory values and patient-reported outcomes at baseline and again 1 year later, and obtained demographic, injury, and military service data from the Expeditionary Medical Encounter Database. The David Grant USAF Medical Center Institution Review Board (IRB) and the Naval Health Research Center IRB reviewed and approved the study protocols.

RESULTS

During recruitment for the pilot study, 624 study candidates were identified from WWRP. Of the 397 candidates we contacted about the pilot study, 179 (45.1%) enrolled and 119 (66.4%) of those who enrolled completed the first year of participation. The second study year was suspended due to the coronavirus disease-2019 pandemic. At the time of suspension, 72 (60.5%) participants completed follow-up laboratory appointments, and 111 (93.3%) completed second-year WWRP assessments. Participants in the pilot study were predominately male (95.0%) and non-Hispanic White (55.5%), with a median (interquartile range) age of 38.3 (34.1-45.4) years.

CONCLUSIONS

Collection of patient-reported outcomes and laboratory samples in a geographically dispersed cohort of combat-injured service members is possible. While significant challenges exist, our pilot study results indicate that a larger, longitudinal, cohort study is feasible.

Longitudinal mental health outcomes of combat-injured service members

BACKGROUND

The relationship between traumatic injury and subsequent mental health diagnoses is not well understood and may have significant implications for patient screening and clinical intervention. We sought to determine the adjusted association between traumatic injury and the subsequent development of post-traumatic stress disorder (PTSD), depression, and anxiety.

METHODS

Using Department of Defense and Veterans Affairs datasets between February 2002 and June 2016, we conducted a retrospective cohort study of 7,787 combat-injured United States service members matched 1:1 to combat-deployed, uninjured service members. The primary exposure was combat injury versus no combat injury. Outcomes were diagnoses of PTSD, depression, and anxiety, defined by International Classification of Diseases 9th and 10th Revision Clinical Modification codes.

RESULTS

Compared to noninjured service members, injured service members had higher observed incidence rates per 100 person-years for PTSD (17.1 vs. 5.8), depression (10.4 vs. 5.7), and anxiety (9.1 vs. 4.9). After adjustment, combat-injured patients were at increased risk of development of PTSD (HR 2.92, 95%CI 2.68-3.17), depression (HR 1.47, 95%CI 1.36-1.58), and anxiety (HR 1.34, 95%CI 1.24-1.45).

CONCLUSIONS

Traumatic injury is associated with subsequent development of PTSD, depression, and anxiety. These findings highlight the importance of increased screening, prevention, and intervention in patients with exposure to physical trauma.

Mental Health Outcomes Among Military Service Members After Severe Injury in Combat and TBI

INTRODUCTION

Studies examining the mental health outcomes of military personnel deployed into combat zones have focused on the risk of developing post-traumatic stress disorder conferred by mild or moderate traumatic brain injury (TBI). However, other mental health outcomes among veterans who sustained critical combat injuries have not been described.

MATERIALS AND METHOD

We examined the associations of moderate and severe TBI and combat injury with the risk for anxiety and mood disorders, adjustment reactions, schizophrenia and other psychotic disorders, cognitive disorders, and post-traumatic stress disorder. We conducted a retrospective cohort study of U.S. military service members critically injured in combat during military operations in Iraq and Afghanistan from February 1, 2002, to February 1, 2011. Health care encounters from (1) the Department of Defense (DoD) Trauma Registry (TR), (2) acute and ambulatory care in military facilities, and (3) civilian facilities are reimbursed by Tricare. Service members who sustained severe combat injury require critical care. We estimated the risk of mental health outcomes using risk-adjusted logit models for demographic and clinical factors. We explored the relationship between TBI and the total number of mental health diagnoses.

RESULTS

Of the 4,980 subjects who met inclusion criteria, most injuries occurred among members of the Army (72%) or Marines (25%), with mean (SD) age of 25.5(6.1) years. The prevalence of moderate or severe TBI was 31.6% with explosion as the most common mechanism of injury (78%). We found 71% of the cohort was diagnosed with at least one poor mental health condition, and the adjusted risk conferred by TBI ranged from a modest increase for anxiety disorder (odds ratio, 1.27; 95% confidence interval [CI], 1.11-1.45) to a large increase for cognitive disorder (odds ratio, 3.24; 95% CI, 2.78-3.77). We found TBI was associated with an increased number of mental health diagnoses (incidence rate ratio, 1.52; 95% CI, 1.42-1.63).

CONCLUSIONS

Combat-associated TBI may have a broad effect on several mental health conditions among critically injured combat casualties. Early recognition and treatment for trauma-associated mental health are crucial to improving outcomes among service personnel as they transition to post-deployment care in the DoD, Department of Veterans Affairs, or community health systems.

The Enduring Health Consequences of Combat Trauma: a Legacy of Chronic Disease

BACKGROUND

A better understanding of the long-term health effects of combat injury is important for the management of veterans' health in the Department of Defense (DoD) and Veterans Affairs (VA) health care systems and may have implications for primary care management of civilian trauma patients.

OBJECTIVE

To determine the impact of traumatic injury on the subsequent development of hypertension (HTN), diabetes mellitus (DM), and coronary artery disease (CAD) after adjustment for sociodemographic, health behavior, and mental health factors.

DESIGN

Retrospective cohort study of current and former US military personnel with data obtained from both the DoD and VA health care systems.

PARTICIPANTS

Combat injured (n = 8727) service members between 1 February 2002 and 14 June 2016 randomly selected from the DoD Trauma Registry matched 1:1 based on year of birth, sex, and branch of service to subjects that deployed to a combat zone but were not injured.

MAIN MEASURES

Traumatic injury, stratified by severity, compared with no documented injury. Diagnoses of HTN, DM, and CAD defined by International Classification of Diseases 9th or 10th Revision Clinical Modification codes.

KEY RESULTS

After adjustment, severe traumatic injury was significantly associated with HTN (HR 2.78, 95% CI 2.18-3.55), DM (HR 4.45, 95% CI 2.15-9.18), and CAD (HR 4.87, 95% CI 2.11-11.25), compared with no injury. Less severe injury was associated with HTN (HR 1.14, 95% CI 1.05-1.24) and CAD (HR 1.62, 95% CI 1.11-2.37).

CONCLUSIONS

Severe traumatic injury is associated with the subsequent development of HTN, DM, and CAD. These findings have profound implications for the primary care of injured service members in both the DoD/VA health systems and may be applicable to civilian trauma patients as well. Further exploration of pathophysiologic, health behavior, and mental health changes after trauma is warranted to guide future intervention strategies.

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.

TBI weight-drop model with variable impact heights differentially perturbs hippocampus-cerebellum specific transcriptomic profile

The degree of brain injury is the governing factor for the magnitude of the patient's psycho- and physiological deficits post-injury, and the associated long-term consequences. The present scaling method used to segregate the patients among mild, moderate and severe phases of traumatic brain injury (TBI) has major limitations; however, a more continuous stratification of TBI is still elusive. With the anticipation that differentiating molecular markers could be the backbone of a robust method to triage TBI, we used a modified closed-head injury (CHI) Marmarou model with two impact heights (IH). By definition, IH directly correlates with the impact force causing TBI. In our modified CHI model, the rat skull was fitted with a helmet to permit a diffuse axonal injury. With the frontal cortex as the focal point of injury, the adjacent brain regions (hippocampus, HC and cerebellum, CB) were susceptible to diffuse secondary shock injury. At 8 days post injury (po.i.), rats impacted by 120 cm IH (IH₁₂₀) took a longer time to find an escape route in the Barnes maze as compared to those impacted by 100 cm IH (IH₁₀₀). Using a time-resolved interrogation of the transcriptomic landscape of HC and CB tissues, we mined those genes that altered their regulations in correlation with the variable IHs. At 14 days po.i., when all rats demonstrated nearly normal visuomotor performance, the bio-functional analysis suggested an advanced healing mechanism in the HC of IH₁₀₀ group. In contrast, the HC of IH₁₂₀ group displayed a delayed healing with evidence of active cell death networks. Combining whole genome rat microarrays with behavioral analysis provided the insight of neuroprotective signals that could be the foundation of the next generation triage for TBI patients.

Long-term negative emotional outcomes of warzone TBI

OBJECTIVE

Many veterans of the Iraq and Afghanistan Wars have experienced traumatic brain injury (TBI). Although prior work has examined associations between TBI and development of psychiatric syndromes, less is known about associations between TBI and component emotions constituting these syndromes, especially in the long term. The purpose of this study was to examine the long-term emotional consequences of deployment-related TBI.

METHODS

As part of VA Cooperative Studies Program #566, we assessed a sample of n = 456 US Army soldiers prior to an index deployment to Iraq, and again an average of 8.3 years (SD = 2.4 years) after their deployment for a long-term follow-up assessment. In this report, we used adjusted regression analyses to examine the relationship of deployment TBI to depression, anxiety, and stress symptom severity measured at the long-term follow-up assessment. A structured interview was used to determine TBI history; the Depression, Anxiety, and Stress Scale, 21-item version (DASS-21) was used to determine emotional status at the follow-up evaluation.

RESULTS

Warzone TBI events, particularly when greater than mild in severity, were independently associated with depression, anxiety, and stress severity at long-term follow-up, even after taking into account variance attributable to pre-deployment emotional distress and war-zone stress. Post-hoc analyses did not detect independent associations of either number of events or injury mechanism with outcomes.

CONCLUSIONS

These findings highlight the potentially enduring and multi-faceted emotional effects of deployment TBI, underscoring the need for early assessment of negative affectivity in warzone veterans reporting TBI.

Establishment of a Patient-Centered Outcomes Research Network for Individuals with TBI and Neuropsychiatric Symptoms

Aims: The overarching goal of this project was to establish a group comprised of a variety of TBI stakeholders for the purpose of: (1) determining facilitators and barriers in management of neuropsychiatric symptoms after TBI; (2) identifying strategies for maintaining a TBI PCOR network; (3) enumerating research topics related to TBI neuropsychiatry; and (4) highlighting policy changes related to TBI neuropsychiatry.Methods: Twenty-nine TBI stakeholders participated in focus group discussions. Qualitative analyses were conducted both manually and using Dedoose software.Results: Participant-identified barriers included stigma associated with experiencing neuropsychiatric symptoms and poor insurance coverage. Facilitators included treatment focused on education of neuropsychiatric symptoms after TBI and having a comprehensive caregiver plan. Best strategies for maintaining TBI PCOR network included having a well-defined project, continued regular meetings, and on-going education of network members. Pertinent research topics included TBI and aging, factors influencing outcomes after TBI, substance use disorders related to TBI, and effectiveness of telemental health services. Needed policy changes included making TBI neuropsychiatry education accessible to stakeholders and improving accessibility of TBI neuropsychiatric care.Conclusion: TBI stakeholders identified several facilitators of care for neuropsychiatric symptoms after TBI and suggested research topics and best practices for conducting PCOR in this area.

Deployment, suicide, and overdose among comorbidity phenotypes following mild traumatic brain injury: A retrospective cohort study from the Chronic Effects of Neurotrauma Consortium

Mild traumatic brain injury in the Veteran population is frequently comorbid with pain, post-traumatic stress disorder, and/or depression. However, not everyone exposed to mild traumatic brain injury experiences these comorbidities and it is unclear what factors contribute to this variability. The objective of this study was to identify comorbidity phenotypes among Post-9/11 deployed Veterans with no or mild traumatic brain injury and examine the association of comorbidity phenotypes with adverse outcomes. We found that Veterans with mild traumatic brain injury (n = 93,003) and no brain injury (n = 434,378) were mean age of 32.0 (SD 9.21) on entering Department of Veterans Health Administration care, were predominantly Caucasian non-Hispanic (64.69%), and served in the Army (61.31%). Latent class analysis revealed five phenotypes in each subcohort; Moderately Healthy and Mental Health phenotypes were common to both. The Healthy phenotype was found only in no brain injury. Unique phenotypes in mild traumatic brain injury included Moderately Healthy+Decline, Polytrauma, and Polytrauma+Improvement. There was substantial variation in adverse outcomes. The Polytrauma+Improvement phenotype had the lowest likelihood of adverse outcomes. There were no differences between Moderately Healthy+Decline and Polytrauma phenotypes. Phenotypes of comorbidity vary significantly by traumatic brain injury status including divergence in phenotypes (and outcomes) over time in the mild traumatic brain injury subcohort. Understanding risk factors for the divergence between Polytrauma vs. Polytrauma+Improvement and Moderately Healthy vs. Moderately Healthy+Decline, will improve our ability to proactively mitigate risk, better understand the early patterns of comorbidity that are associated with neurodegenerative sequelae following mild traumatic brain injury, and plan more patient-centered care.