Traumatic Brain Injury Following Military Deployment: Evaluation of Diagnosis and Cause of Injury.

OBJECTIVE: To evaluate the prevalence of delayed traumatic brain injury (TBI) diagnosis and cause of injury that resulted in a TBI diagnosis after military deployment. DESIGN: Medical record notes were reviewed in 2016 from a random sample of 1150 US military service members who had their first-time deployment in 2011 and likely sustained a TBI. Location and cause of the injury were extracted from the progress note for analysis. PARTICIPANTS AND SETTING: Active-duty US military service members who received an International Classification of Diseases, Ninth Revision code for a TBI diagnosis in a military facility. MAIN OUTCOME MEASURES: Presence of TBI, location of injury, cause of injury, and time of diagnosis with respect to deployment. RESULTS: The odds of being diagnosed with a deployment-related TBI were 8 times higher during the first 4 weeks upon return from deployment than the subsequent 32 weeks. The likelihood of diagnosing a deployment-sustained TBI during weeks 5 to 32 was 2 times higher than during 33 to 76 weeks following return from deployment. The proportion of deployment-related TBI diagnoses decreased with time following return from deployment but remained above 40% during weeks 33 to 76. Service branch, gender, race, occupation, and time between TBI diagnosis and return from deployment were significant predictors of deployment-related TBIs. Moving motor vehicle, sports, parachute, and being struck by objects were the top causes of injury in garrison (nondeployed setting), whereas blast produced the majority (66%) of all causes of injuries that resulted in a TBI in the deployed setting. CONCLUSION: The increased incidence rate of a TBI diagnosis following deployment can be attributed to delayed diagnosis of TBI sustained from injuries during deployment. TBIs sustained during deployment can be diagnosed beyond the initial 4 weeks after return from deployment and may continue up to 76 weeks following return from deployment.

Incidence of Traumatic Brain Injury in the U.S. Military, 2010-2014.

INTRODUCTION: Traumatic brain injury (TBI) is a significant health issue that affects U.S. military service members (SM) at home and in combat deployments. We estimated the TBI incidence rate in the deployed and non-deployed setting between 2010 and 2014 and identified subgroups with elevated rates for prevention efforts. METHODS: Retrospective population-based study of all active duty U.S. military SM that sustained a first active duty TBI diagnosis between January 2010 and December 2014 collected and analyzed in 2017. Using Armed Forces Health Surveillance Branch data we calculated the Mantel-Haenszel (MH) standardized TBI incidence rate in the deployed and non-deployed setting, adjusting for service and demographic factors. RESULTS: From 2010 to 2014, the MH standardized incidence rate for deployed SMs was 3,265 TBIs per 100 thousand p-yrs (95% CI: 3,222-3,307) and 1,705.2 (95% CI: 1,694.0-1,716.5) for non-deployed SMs. The youngest deployed male Army soldiers, those ages 17-24, especially White and Hispanic soldiers, had the highest TBI incidence rate (IR) of 5,748.7 (95% CI: 5,585.8-5,916.4) and 5,010.3 (95% CI: 4,647.5-5,401.4), respectively. The IR for all branches was 1,972.6 (95% CI: 1,959.5-1,985.7) and 724.0 (95% CI: 714.9-733.0) for Reserve/Guard Service members. CONCLUSIONS: Across all years, Marines and Army Soldiers experience the highest rates of injury with deployed SMs having elevated IRs of TBI. The TBI IR among deployed SMs was 91% higher than among those in the non-deployed setting, due to continued exposures to combat. Deployed Reserve/Guard component SMs seem to have an above average rate, a finding with implications for training and prevention.

Mortality Following Hospital Admission for US Active Duty Service Members Diagnosed With Penetrating Traumatic Brain Injury, 2004-2014.

OBJECTIVE: To examine mortality among active duty US military service members (SMs) with the diagnosis of penetrating traumatic brain injury (PTBI) and a hospital admission between 2004 and 2014. DESIGN: Data on SMs with PTBI and an admission to a military or civilian hospital were obtained from the 2004 to 2014 Military Health System data repository. After applying exclusion criteria, data on 1226 SMs were analyzed. MAIN MEASURES: The number of observed deaths per 100 identified patients with PTBI and time to death from admission were used as main measures. RESULTS: Approximately 25% of the 1226 patients with PTBI included in this study died following admission, with 44.6% of the all deaths occurring within a day following hospital admission and 75% occurring within the first week. Severe comorbid conditions and intentionally self-inflicted injuries are associated with higher mortality rate. SMs' gender, age, year of hospital admission, and service were significantly associated with likelihood of death following PTBI hospitalization. Males had a higher likelihood of dying following hospital admission compared with females (odds ratio = 2.7, confidence interval = 1.03-7.9). SMs in the 35- to 44-year-old and 45- to 64-year-old groups had up to a 2.6 times higher odds of death following their admission compared with the 25- to 34-year-old group. Age, admission year, service, and rank were significantly associated with SMs' time to death from hospitalization. Patients between the ages of 45 and 64 years were significantly more likely to die earlier than other age groups. Furthermore, cases in the Navy Afloat group had a higher fatality rate and were more likely to die earlier than patients in other services. PTBI comorbid conditions and injury type did not significantly affect time to death. CONCLUSION: This study quantifies case fatality rate among hospitalized US SMs with the diagnosis of PTBI. We report a 23.1% crude case fatality rate among the current cohort. Early intensive care for these patients may be the key to improving survival rates.

Role of Department of Defense Policies in Identifying Traumatic Brain Injuries Among Deployed US Service Members, 2001-2016.

OBJECTIVES: To examine the role of Department of Defense policies in identifying theater-sustained traumatic brain injuries (TBIs). METHODS: We conducted a retrospective study of 48 172 US military service members who sustained their first lifetime TBIs between 2001 and 2016 while deployed to Afghanistan or Iraq. We used multivariable negative binomial models to examine the changes in TBI incidence rates following the introduction of Department of Defense policies. RESULTS: Two Army policies encouraging TBI reporting were associated with an increase of 251% and 97% in TBIs identified following their implementation, respectively. Among airmen, the introduction of TBI-specific screening questions to the Post-Deployment Health Assessment was associated with a 78% increase in reported TBIs. The 2010 Department of Defense Directive Type Memorandum 09-033 was associated with another increase of 80% in the likelihood of being identified with a TBI among soldiers, a 51% increase among sailors, and a 124% increase among Marines. CONCLUSIONS: Department of Defense and service-specific policies introduced between 2006 and 2013 significantly increased the number of battlefield TBIs identified, successfully improving the longstanding problem of underreporting of TBIs.

Military Deployment May Increase the Risk for Traumatic Brain Injury Following Deployment.

OBJECTIVE: To compare rates of traumatic brain injury (TBI) diagnosis before and after overseas military deployment. DESIGN: We conducted a retrospective examination of a cohort of 119 353 active duty US military service members (Army, Navy, Air Force, and Marines) whose first lifetime overseas deployment began at any time between January 1, 2011, and December 31, 2011, and lasted at least for 30 days. For this cohort, TBI diagnoses were examined during the 76 weeks prior to deployment, during deployment, and 76 weeks following the end of deployment. MAIN MEASURES: 4-week rates of TBI diagnosis. RESULTS: The risk of being diagnosed with TBI within 4 weeks after returning from deployment was 8.4 times higher than the average risk before deployment. The risk gradually decreased thereafter up to 40 weeks postdeployment. However, during the 41 to 76 weeks following deployment, risk stabilized but remained on average 1.7 times higher than before deployment. CONCLUSION: An increased rate of TBI diagnosis following deployment was identified, which may be partly due to delayed diagnosis of TBIs that occurred while service members were deployed. Also, the increased rate may partly be due to riskier behaviors of service members following deployment that results in an increased occurrence of TBIs.