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Abstract
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n August 30, 2021, the last US military service members left Afghanistan, marking the end of America's longest war. It is important to continue to examine the impact of the war on service members, veterans, family members, clinicians, and health care systems. Traumatic brain injuries (TBIs) are often described as one of the signature injuries of the war. Estimates of TBI among service members who have returned from military operations in Iraq and Afghanistan vary moderately, which highlights the critical importance of TBI definitions and methods to ascertain TBI exposure. Estimates suggest that between 9% and 28% of service members experienced a TBI.1 Complicating matters further, many veterans experienced 1 or more TBIs before their military service, thereby suggesting that military-related injuries may be neither the first nor the worst lifetime injury sustained. Regardless of the true prevalence of TBI, it is clear that TBI represents a major health care issue for veterans. Additional research is needed to understand the long-term health outcomes for veterans with TBIs. The results should guide clinical, research, and policy-based decisions.
Within this context, the analyses by Howard and colleagues2 represent a timely contribution examining the association of TBI severity with mortality among more than 2.5 million veterans serving after September 11, 2001 (9/11). These secondary analyses were conducted as part of a larger study designed to examine health trajectories over time. Therefore, Howard et al2 were right to highlight their limitations; this was not a population-based cohort study of all post-9/11 TBI cases. Cases were required to have 3 or more years of Department of Defense (DoD) health care, and 2 or more years of Veterans Health Administration (VHA) care for those who entered the VHA; therefore, these results should be confirmed in future studies. The authors found that all-cause mortality was higher among post-9/11 military veterans compared with the general population, and the differences increased along with TBI severity, especially among older veterans.2 Different patterns emerged when external causes of death (ie, accidents, suicide, and homicides), cancer, and cardiovascular disease were examined separately; rates of external causes of death were especially high among those with a moderate-to-severe TBI. The authors calculated excess death estimates. Although only 3% of the post-9/11 cohort had a moderate-to-severe TBI, they accounted for 33.6% of total excess deaths.2
The study by Howard et al2 highlights challenges identified early in the war as TBI evolved as a critical issue. How should TBI be defined? What methods should be used to ascertain TBI cases? Despite substantial progress on these issues, many researchers are forced to make trade-off decisions that balance feasibility with reference standard methods. These methodological issues create challenges for identifying the true rate of TBI, injury severity, and short- and long-term outcomes associated with such injuries (eg, mortality and cause of death). In this study,2 TBI cases were identified at least in part with TBI screening procedures for deployment-related injuries. Challenges and limitation associated with VHA and DoD screening procedures have been previously discussed3 and should be considered in the interpretation of the results. Without substantial and coordinated efforts, challenges with screening and diagnostic definitions are expected to persist. Efforts to refine diagnostic definitions for TBI, as well as future signature injuries, should be prioritized. This will facilitate valid and reliable case identification and advance the development of interventions to help service members and veterans.
The findings presented by Howard and colleagues2 are relatively consistent with previously published literature. History of TBI (all levels of severity) is associated with both mood-related symptoms (eg, depression), as well as new or exacerbated psychiatric conditions (eg, posttraumatic stress disorder). In addition, those with TBI and, in particular, more severe injury often cope with secondary health conditions (eg, obesity, chronic pain) that are known to be related to increased risk for conditions associated with mortality. For example, Harrison-Felix and colleagues4 found that those who received civilian inpatient rehabilitation for TBI were 1.5 times more likely to die than members of the general population and had an estimated average life expectancy reduction of 4 years. Rates of death secondary to suicide, aspiration pneumonia, other pneumonias, digestive conditions, and seizures were greater than expected...
Language: en |