Clinical Trajectories of Comorbidity Associated With Military-Sustained Mild Traumatic Brain Injury: Pre- and Post-Injury

Abstract

Background and Objective: In the US military, traumatic brain injury (TBI) is of distinct importance, at home and in the deployed setting, and is considered a “signature injury of the wars in Afghanistan and Iraq.” Since 2000, an estimated 468 424 service members (SMs) have been diagnosed with at least one TBI. We examined the clinical trajectories of a group of 18 comorbidities before and after a military-sustained mild TBI (mTBI). Methods: Without making assumptions on causality, a group of 18 conditions often co-occurring with mTBI were identified through literature review and TBI subject matter workgroup consensus. Using data from Military Health System Data Repository, we identified SMs whose first lifetime military mTBI occurred between October 1, 2016, and October 30, 2019. Correlation analyses were used to determine the linear relationship between comorbidities prior to and after mTBI diagnosis. Changes in the period prevalence of comorbidities was calculated. Results: We identified 42 018 SMs with a first lifetime military mTBI, of which 77.6% had at least one comorbidity. Identified SMs were mostly young (46.1% ages 18-24 years), male (81.4%), and White (64.1%). Up to 180 days prior to an mTBI, the most frequently identified conditions were sleep-related conditions (21.7%), headaches (19.4%), posttraumatic stress disorders (PTSDs) (17.8%), anxiety disorders (11.3%), and cervicogenic disorders (eg, cervicalgia) (10.9%). In the period following mTBI diagnosis, the prevalence of diagnosed conditions increased, especially for visual disturbances (327.2%), cognitive conditions (313.9%), vestibular conditions (192.6%), those related to headache (152.2%), and hearing (72.9%). Sleep-related conditions showed moderate positive correlation with a group of co-occurring conditions, led by cognitive conditions (ϕc = 0.50), anxiety disorders (ϕc = 0.42), PTSDs (ϕc =0.43), and headaches and related conditions (ϕc = 0.38). Conclusion: Results indicate that caring for SMs with mild TBI requires a holistic approach, one that considers the complex nature of SM conditions, prior to sustaining their mTBI, as well as after injury. We found a complex correlation of conditions that suggest SMs with mTBI are undergoing a multifaceted experience, one that may require the development of a targeted multidimensional clinical practice recommendation and practice.