Sex Differences in Postinjury Health Profiles Among U.S. Military Personnel Following Deployment-Related Concussion.

Background: Women in the U.S. military are now authorized to serve in direct combat occupations. This may increase their risk of combat injuries, such as concussion, in future conflicts. Knowledge of sex differences in health profiles after concussion is paramount for military medical planning efforts. The purpose of this study was to assess sex-related differences in health profiles among U.S. military personnel following deployment-related concussion. Materials and Methods: We conducted a retrospective study of service members who sustained a concussion during combat deployment between 2004 and 2013. Postinjury diagnoses were abstracted from outpatient encounters in electronic health records for 24 months after concussion. We used hierarchical clustering to identify clusters, termed "health profiles," and logistic regression to determine whether sex predicted membership in the health profiles. Results: The study sample included 346 women and 4536 men with deployment-related concussion. Five postinjury health profiles were identified and classified as no morbidity, back pain, tinnitus/memory loss, posttraumatic stress disorder/postconcussion syndrome, and multimorbidity. Women relative to men had higher odds of membership in the back pain (odds ratio [OR] = 1.32; 95% confidence interval [CI] = 1.05-1.67) and multimorbidity profiles (OR = 1.44; 95% CI = 1.03-2.00) and lower odds than men in the tinnitus/memory loss profile (OR = 0.62; 95% CI = 0.42-0.91). Conclusions: Postinjury health profiles among U.S. service members differ by sex following deployment-related concussion, particularly with a higher burden of multimorbidity among women than men, which may require interdisciplinary care. Women also had higher odds of membership in the back pain profile and lower odds in the tinnitus/memory loss profile than men. To prepare for future military operations where women may have greater exposure to combat, continued research elucidating health-related sex differences after deployment-related concussion is imperative.

Investigating insomnia in United States deployed military forces: A topic modeling approach.

STUDY OBJECTIVES: This retrospective study analyzed free-text clinical notes from medical encounters for insomnia among a sample of deployed US military personnel. Topic modeling, a natural language processing technique, was used to identify thematic patterns in the clinical notes that were potentially related to insomnia diagnosis. METHODS: Clinical notes of patient clinical encounters coded for insomnia from the US Department of Defense Military Health System Theater Medical Data Store were analyzed. Following preprocessing of the free text in the clinical notes, topic modeling was employed to identify relevant underlying topics or themes in 32,864 unique patients. The machine-learned topics were validated using human-coded potential insomnia etiological issues. RESULTS: A 12-topic model was selected based on quantitative metrics, interpretability, and coherence of terms comprising topics. The topics were assigned the following labels: personal/family history, stimulants, stress, family/relationships, other sleep disorders, depression, schedule/environment, anxiety, other medication, headache/concussion, pain, and medication refill. Validation of these topics (excluding the two medication topics) against their corresponding human-coded potential etiological issues showed strong agreement for the assessed topics. CONCLUSIONS: Analysis of free-text clinical notes using topic modeling resulted in the identification of thematic patterns that largely mirrored known correlates of insomnia. These findings reveal multiple potential etiologies for deployment-related insomnia. The identified topics may augment electronic health record diagnostic codes and provide valuable information for sleep researchers and providers. As both civilian and military healthcare systems implement electronic health records, topic modeling may be a valuable tool for analyzing free-text data to investigate health outcomes.

The Psychological Consequences of Combat Injury Among U.S. Navy Health Care Personnel.

INTRODUCTION: Military health care personnel face numerous risks to mental health, including those associated with combat injury, although no study has described combat injuries within this subgroup or assessed their impact on mental health outcomes. MATERIALS AND METHODS: Male U.S. Navy-enlisted health care personnel, or corpsmen, with combat injury were identified from clinical records. Noninjured corpsmen were matched to injured corpsmen with a 4:1 ratio on year of deployment end or injury and location (Iraq or Afghanistan). The final study population included 2,025 corpsmen (405 injured and 1,620 noninjured). Mental health disorders assessed included posttraumatic stress disorder (PTSD), anxiety, adjustment, mood, and substance abuse disorders. Stratified Cox models were used for analysis while controlling for additional covariates, and injury severity was evaluated as a predictor. RESULTS: Injuries primarily involved the head/neck (73.8%) and extremities (45.7%), and overall injury severity was mostly mild-to-moderate (85.9%). Injured relative to noninjured corpsmen had greater risk of PTSD (risk ratio [RR] 2.45, 95% confidence interval [CI] 2.05 to 2.94), anxiety disorder (RR 1.61, 95% CI 1.32 to 1.96), adjustment disorder (RR 1.88, 95% CI 1.55 to 2.27), mood disorder (RR 1.44, 95% CI 1.16 to 1.79), and substance abuse (RR 1.48, 95% CI 1.14 to 1.91). More severe injuries yielded stronger associations with PTSD (RR 3.57, 95% CI 2.48 to 5.14), anxiety disorder (RR 2.53, 95% CI 1.74 to 3.69), and adjustment disorder (RR 2.17, 95% CI 1.44 to 3.27). CONCLUSIONS: U.S. Navy corpsmen are at risk of combat injury and associated mental health disorders. Injured corpsmen should be screened for mental health problems in the acute phase postinjury, during their remaining time in theater, and after returning home. Future research should address how combat injury compares with other stressors that health care personnel experience and whether the psychological consequences of these injuries (e.g., PTSD) negatively impact work performance and increase risk of burnout.

Health Profiles of Military Women and the Impact of Combat-Related Injury.

PURPOSE: The role of women in the United States military is expanding. Women are now authorized to serve in all military occupations, including special operations and frontline combat units, which places them at increased risk of combat exposure and injury. Little is known regarding the impact of these injuries on the health of military women. METHODS: We conducted a retrospective matched cohort study of women service members who were injured during combat operations in Iraq and Afghanistan. Injured women were individually matched to non-injured controls at a 1:4 ratio. Medical diagnostic codes were abstracted from outpatient encounters in electronic health records, and hierarchical clustering was conducted to identify clusters of diagnostic codes, termed "health profiles." Conditional logistic regression was used to determine whether combat-related injury predicted membership in the profiles. RESULTS: The study sample included 590 injured women and 2360 non-injured controls. Cluster analysis identified six post-deployment health profiles: low morbidity, anxiety/headache, joint disorders, mixed musculoskeletal, pregnancy-related, and multimorbidity. Combat-related injury predicted membership in the anxiety/headache (odds ratio, 1.73; 95% confidence interval, 1.38-2.16) and multimorbidity (odds ratio, 3.43; 95% confidence interval, 2.65-4.43) profiles. CONCLUSIONS: Combat-related injury is associated with adverse post-deployment health profiles among military women, and women with these profiles may experience increased health care burden. As future conflicts will likely see a greater number of women with combat exposure and injury, health outcomes research among military women is paramount for the purposes of medical planning and resource allocation.

Symptom profiles following combat injury and long-term quality of life: a latent class analysis.

PURPOSE: The purpose of this study was to identify symptom profiles among U.S. military personnel within 1 year after combat injury and assess the relationship between the symptom profiles and long-term quality of life (QoL). METHODS: The study sample consisted of 885 military personnel from the Expeditionary Medical Encounter Database who completed (1) a Post-Deployment Health Assessment (PDHA) within 1 year following combat injury in Iraq or Afghanistan, and (2) a survey for the Wounded Warrior Recovery Project (WWRP), a longitudinal study tracking patient-reported outcomes (e.g., QoL) in injured military personnel. Fifteen self-reported symptoms from the PDHA were assessed using latent class analysis to develop symptom profiles. Multivariable linear regression assessed the predictive effect of symptom profiles on QoL using the physical (PCS) and mental (MCS) component summary scores from the 36-Item Short Form Survey included in the WWRP. Time between PDHA and WWRP survey ranged from 4.3 to 10.5 years (M = 6.6, SD = 1.3). RESULTS: Five distinct symptom profiles were identified: low morbidity (50.4%), multimorbidity (15.6%), musculoskeletal (14.0%), psycho-cognitive (11.1%), and auditory (8.9%). Relative to low morbidity, the multimorbidity (ß = - 5.45, p < 0.001) and musculoskeletal (ß = - 4.23, p < 0.001) profiles were associated with lower PCS, while the multimorbidity (ß = - 4.25, p = 0.002) and psycho-cognitive (ß = - 3.02, p = 0.042) profiles were associated with lower MCS. CONCLUSION: Multimorbidity, musculoskeletal, and psycho-cognitive symptom profiles were the strongest predictors of lower QoL. These profiles can be employed during screening to identify at-risk service members and assist with long-term clinical planning, while factoring in patient-specific impairments and preferences.

Multimorbidity and quality of life after blast-related injury among US military personnel: a cluster analysis of retrospective data.

BACKGROUND: Blast injury emerged as a primary source of morbidity among US military personnel during the recent conflicts in Iraq and Afghanistan, and led to an array of adverse health outcomes. Multimorbidity, or the presence of two or more medical conditions in an individual, can complicate treatment strategies. To date, there is minimal research on the impact of multimorbidity on long-term patient-reported outcomes. We aimed to define multimorbidity patterns in a population of blast-injured military personnel, and to examine these patterns in relation to long-term quality of life (QOL). METHODS: A total of 1972 US military personnel who sustained a blast-related injury during military operations in Iraq and Afghanistan were identified from clinical records. Electronic health databases were used to identify medical diagnoses within the first year postinjury, and QOL was measured with a web-based assessment. Hierarchical cluster analysis methods using Ward's minimum variance were employed to identify clusters with related medical diagnosis categories. Duncan's multiple range test was used to group clusters into domains by QOL. RESULTS: Five distinct clusters were identified and grouped into three QOL domains. The lowest QOL domain contained one cluster with a clinical triad reflecting musculoskeletal pain, concussion, and mental health morbidity. The middle QOL domain had two clusters, one with concussion/anxiety predominating and the other with polytrauma. The highest QOL domain had two clusters with little multimorbidity aside from musculoskeletal pain. CONCLUSIONS: The present study described blast-related injury profiles with varying QOL levels that may indicate the need for integrated health services. Implications exist for current multidisciplinary care of wounded active duty and veteran service members, and future research should determine whether multimorbidity denotes distinct post-blast injury syndromes.

Odds of hospitalization among Marine Corps personnel by military occupational specialty and causative agents during OEF and OIF.

OBJECTIVE: This study investigated the risk of hospitalization among Marines deployed during Operations Enduring and Iraqi Freedom by military occupational specialty (MOS). METHODS: Trends in risk of hospitalization as a function of injury cause (explosive munitions and small arms [EM/SA]), anatomical location, and injury type were analyzed to identify which MOSs were more likely to have open wound injuries or trauma to the extremities. The study population consisted of 163,939 Marines deployed at any time during the study period (September 11, 2001-January 31, 2007). Hospitalized Marines (n=2718) were matched to nonhospitalized Marines on rank, time deployed, and number of deployments. RESULTS: Noninfantry MOSs had lower risk of hospitalization compared with infantry, regardless of injury cause or location. Trends differed for EM/SA versus other injury causative agents, but did not differ by anatomical location among EM/SA. CONCLUSION: This information allows for quantitative assessment of risk by MOS in combat situations.

Injury and illness casualty distributions among U.S. Army and Marine Corps personnel during Operation Iraqi Freedom.

The objective of this study was to evaluate the distributions of U.S. Marine Corps and Army wounded in action (WIA) and disease and nonbattle injury (DNBI) casualties during Operation Iraqi Freedom Major Combat Phase (OIF-1) and Support and Stability Phase (OIF-2). A retrospective review of hospitalization data was conducted. chi2 tests were used to assess the Primary International Classification of Diseases, 9th Revision (ICD-9), diagnostic category distributions by phase of operation, casualty type, and gender. Of the 13,071 casualties identified for analysis, 3,263 were WIA and 9,808 were DNBI. Overall, the proportion of WIA was higher during OIF-1 (36.6%) than OIF-2 (23.6%). Marines had a higher proportion of WIA and nonbattle injuries than soldiers. Although overall DNBI distributions for men and women were statistically different, their distributions of types of nonbattle injuries were similar. Identifying differences in injury and illness distributions by characteristics of the casualty population is necessary for military medical readiness planning.

The Navy-Marine Corps Combat Trauma Registry.

The U.S. military services, drawing on the experiences of civilian trauma systems in monitoring trauma care delivery, have begun to implement their own registries, emphasizing injury incidence and severity in a combat environment. This article introduces and describes the development of the U.S. Navy-Marine Corps Combat Trauma Registry and presents several preliminary inquiries of its database regarding combat injury patterns and casualty management during Operation Iraqi Freedom. The Navy-Marine Corps Combat Trauma Registry is composed of data sets describing events that occur from the point of injury through the medical chain of evacuation and on to long-term rehabilitative outcomes. Data were collected from Navy-Marine Corps level 1B, 2, and 3 medical treatment facilities. Data from the official combat period were analyzed to present a variety of preliminary findings that indicate, among other things, how many and for what type of injury casualties were evacuated, specific mechanisms of injury, and types of injuries treated at the medical treatment facilities.

Wounding patterns for U.S. Marines and sailors during Operation Iraqi Freedom, major combat phase.

This investigation examined the wounds incurred by 279 U.S. Navy-Marine personnel (97% Marines and 3% sailors) identified as wounded in action during Operation Iraqi Freedom, from March 23 through April 30, 2003. The goal was to assess the potential impact of each causative agent by comparing the differences in anatomical locations, types of injuries caused, and medical specialists needed to treat the casualties. The overall average number of diagnoses per patient was 2.2, and the overall average number of anatomical locations was 1.6. The causative agents were classified into six major categories, i.e., small arms, explosive munitions, motor vehicle accidents, falls, weaponry accidents, and other/unknown. Explosive munitions and small arms accounted for approximately three of four combat-related injuries. Upper and lower extremities accounted for approximately 70% of all injuries, a percentage consistent for battlefield injuries since World War II.

An assessment of the potential for reducing future combat deaths through medical technologies and training.

BACKGROUND: We examined clinical records of combat casualties that died subsequent to reaching a medical treatment facility in an effort to determine whether new medical technologies or enhanced training might contribute to a reduction in combat deaths. METHODS: Hospital records of 210 fatal combat casualties were independently reviewed by four surgeons. The surgeons assessed each fatality to determine whether it would be preventable if the trauma were sustained today and treated with currently available technology and training. RESULTS: In 8% of the cases, the four surgeons independently agreed that the deaths would be possibly preventable if the same traumas were incurred today. In an additional 17% of the cases, three of the four surgeons judged the deaths to be possibly preventable today. Causes of death viewed as most likely to be salvageable today included hemorrhage, severe burns, pulmonary edema, and sepsis. The medical technologies most often mentioned to have a potentially lifesaving effect were ventilators/respirators, computed tomographic scanners, ultrasound, and antibiotics. Areas of training most often mentioned to have a potential impact on the salvageability of the trauma cases reviewed were damage control, ventilator management, liver packing, respiratory distress management, and burn management. CONCLUSION: Surgeons reviewing records of past combat deaths indicated that reductions in the incidence of combat deaths through deployment of improved medical technologies and training is possible. Deployment of the noted technologies and proficiency in the cited training has the potential for reducing deaths by 8% to 25% when compared with the died-in-hospital incidence among casualties in the last sustained conflict.