Symptoms of Traumatic Brain Injury and Alzheimer's Disease and Their Impact on Military Service Members' Quality of Life (QOL) and Caregivers' Burden

Background: The goal of the proposed study is to examine the impact of common symptoms of traumatic brain injury (TBI) and Alzheimer's disease (AD), hereafter called TBI-AD, on the quality of life (QOL) of Service members and military retirees diagnosed with this condition as well as to examine the effect of these common symptoms on their caregivers' burden in the Military Health System (MHS). Much of our understanding of the association between TBI and AD comes from the civilian and Veteran populations' data or from neuroimaging and biomarker analysis using data from Vietnam War Veterans with a history of moderate or severe TBI. However, much remains to be known about how common symptoms of TBI-AD impact patients' QOL and their caregivers' burden given the unique risk factors and comorbidities associated with TBI-AD in the MHS.

Hypotheses: This study hypothesizes that these common symptoms of TBI-AD will have a negative impact on the QOL of Service members and military retirees compared to the comparison group, as well as on the employment status of caregivers of these patients. Also, we hypothesize that these common symptoms of TBI-AD will have a positive impact on the number of hours/days taken off work by caregivers to care for patients diagnosed with TBI-AD, as well as on the burden and depression scores of caregivers compared to the comparison group.

Specific Aims: This study aims to (1) determine the mechanisms through which common symptoms of TBI-AD are associated with this condition in the MHS; (2) examine the effect of common symptoms of TBI-AD on the QOL of Service members and military retirees affected by TBI-AD in the MHS; and (3) examine the effects of common symptoms of TBI-AD on the caregivers of those affected by TBI-AD in the MHS.

Research Strategy: This is a two-phase project. The first phase will use retrospective data from the Military Health System Data Repository (MHS-MDR) and the second phase will use survey data collected on patients diagnosed with TBI-AD and AD only, as well as on their caregivers, to achieve its objectives. We will use the Alzheimer's Disease Related Quality of Life (ADRQL) and the Quality of Life in Alzheimer's disease (QOL-AD) instruments to capture the QOL of patients with TBI-AD and AD only. We will also use several instruments to assess caregivers' burden and measure depression in caregivers. We will include the following common symptoms: memory loss, major depressive disorder, mental disorders, depressive disorder, generalized anxiety disorder, irritability or impulsivity, chronic pain, generalized pain, post-traumatic stress disorder, migraine, other malaise and fatigue, conduct disorder aggressive type, and sleep disturbance. Descriptive analyses using trend charts and frequency tables of means, standard deviations, medians, and confidence intervals will be used to examine differences between groups using T and Chi square tests. Logistic regressions and multiple linear regression models will be used as well to complete the aims stated above.

This proposal is innovative from a conceptual standpoint as it plans to use a series of well-validated instruments that will capture an extensive set of variables that are known to be associated with the QOL of patients and with caregivers' burden. It is innovative from a methodological standpoint as well since it will use administrative claims data from the MHS-MDR to create a randomly selected comparison group of patients diagnosed with AD to minimize the impact of potential sample selection biases between those with TBI-AD compared to those with AD only.

The proposed study is significant in several ways. Findings from this study will help in designing effective intervention programs that aim to improve the QOL of patients and to reduce the caregiving burden for those affected by these common symptoms of TBI-AD in the MHS by taking into account the multiplicative effects of unique risk factors of TBI-AD and associated comorbidities. Findings will underscore the importance of promoting interventions that focus on the needs, characteristics, and circumstances of these patients and their caregivers to ultimately improve patients' and caregivers' outcomes, hence improving military readiness.