Sex Differences in Screening Positive for Post-Traumatic Stress Disorder After Combat Injury.

INTRODUCTION: U.S. military women were at risk of combat exposure and injury from asymmetric warfare during the conflicts in Iraq and Afghanistan. Previous research has yielded mixed results when examining sex differences in PTSD following operational deployment. To date, no study has explored sex differences in PTSD after combat injury. MATERIALS AND METHODS: This retrospective study included U.S. military service men and women who experienced a combat injury in Iraq or Afghanistan (March 2003 to March 2013) and completed a Post-Deployment Health Assessment (PDHA) within 1 year of injury. The PDHA is administered at the end of deployment and includes the 4-item Primary Care PTSD Screen. The prevalence of screening positive for PTSD was evaluated by sex using a chi-square test. Multivariable logistic regression was used to assess the association between sex and PTSD while adjusting for covariates. RESULTS: The study sample included 16,215 injured military personnel (666 women and 15,549 men). The average time between injury and PDHA was 132 days (SD = 91.0). Overall, women had a higher prevalence of screening positive for PTSD than men (48.3% vs. 40.9%, P < .001). In multivariable regression, women had higher odds than men of screening positive for PTSD (odds ratio, 1.34; 95% confidence interval, 1.14-1.57). Psychiatric history was the strongest predictor of screening positive for PTSD regardless of sex (odds ratio, 1.59; 95% confidence interval, 1.45-1.74). CONCLUSIONS: In this novel study of military service members, women were more likely to screen positive for PTSD than men after combat injury. Strategies to mitigate PTSD, enhance resiliency, and incorporate psychological care into injury rehabilitation programs for women may be needed for future U.S. military conflicts where they will play a larger role in combat operations.

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.

Associations between health-related behaviors and self-reported cognitive symptoms in U.S. military personnel injured on deployment.

Health behaviors may be core contributors to cognition and mental health following mild traumatic brain injury (TBI). The aims of the present study examined: (1) whether health behaviors including sleep duration, alcohol use, and physical activity differed in injured military personnel with and without deployment-related mild TBI history and (2) the relative contributions of health behaviors and deployment-related mild TBI history to self-reported cognitive, posttraumatic stress disorder (PTSD), and depressive symptoms. Participants included 3076 military personnel injured on deployment participating in the Wounded Warrior Recovery Project, an ongoing web-based study. Military personnel with deployment-related mild TBI history reported similar rates of physical activity and levels of alcohol problems as those without, but were less likely to report receiving the recommended duration of sleep. When adjusting for demographic and injury variables, all three health behaviors were associated with cognitive, PTSD, and depressive symptoms. Alcohol problems demonstrated significant but small effects across all outcomes measures (ηp2=.01) whereas physical activity was associated with slightly larger effects albeit still within the small range (ηp2=.02-0.04). Duration of sleep bordered a medium effect for cognitive symptoms (ηp2=.05) and was in the medium range for PTSD and depressive symptoms (ηp2=.06). Although deployment-related mild TBI history was significant in all models, effect sizes were small (ηp2=.01). Findings from the present study provide support that health behaviors have stronger effects with regard to cognitive, PTSD, and depressive symptoms compared to deployment-related mild TBI history in military personnel and, given their modifiable nature, may represent treatment targets in this population.

Pre-Existing Audiometric Hearing Loss is a Predictor of Significant Threshold Shift Following Injury During Combat Deployment.

OBJECTIVES: Military personnel are exposed to multiple risk factors for hearing loss, particularly on the battlefield. The objective of this study was to determine whether pre-existing hearing loss predicted hearing threshold shift in male U.S. military personnel following injury during combat deployment. DESIGN: This was a retrospective cohort study with 1573 male military personnel physically injured in Operations Enduring and Iraqi Freedom between 2004 and 2012. Audiograms before and after injury were analyzed and used to calculate significant threshold shift (STS), defined as a 30 dB or greater change in the sum of hearing thresholds at 2000, 3000, and 4000 Hz in either ear on the postinjury audiogram, relative to the same frequencies on the preinjury audiogram. RESULTS: Twenty-five percent (n = 388) of the sample had preinjury hearing loss, which mostly occurred in the higher frequencies (i.e., 4000 and 6000 Hz). The prevalence of postinjury STS ranged from 11.7% to 33.3% as preinjury hearing level moved from better to worse. In multivariable logistic regression, preinjury hearing loss was a predictor of STS, and there was a dose-response relationship between severity of preinjury hearing threshold and postinjury STS, specifically for preinjury hearing levels of 40 to 45 dBHL (odds ratio [OR] = 1.99; 95% confidence interval [CI] = 1.03 to 3.88), 50 to 55 dBHL (OR = 2.33; 95% CI = 1.17 to 4.64), and >55 dBHL (OR = 3.77; 95% CI = 2.25 to 6.34). CONCLUSIONS: These findings suggest that better preinjury hearing provides increased resistance to threshold shift than impaired preinjury hearing. Although STS is calculated using 2000 to 4000 Hz, clinicians must closely attend to the pure-tone response at 6000 Hz and use this test frequency to identify service members at-risk for STS prior to combat deployment.

Deployment-related concussion and long-term health-related quality of life among US military personnel.

PURPOSE: To examine the relationship between deployment-related concussion and long-term health-related quality of life (HRQoL) among injured US military personnel. METHODS: The study sample included 810 service members with deployment-related injuries between 2008 and 2012 who responded to a web-based longitudinal health survey. Participants were categorized into three injury groups: concussion with loss of consciousness (LOC; n = 247), concussion without LOC (n = 317), or no concussion (n = 246). HRQoL was measured using the 36-Item Short Form Health Survey physical and mental component summary (PCS and MCS) scores. Current post-traumatic stress disorder (PTSD) and depression symptoms were examined. Multivariable linear regression models assessed the effects of concussion on PCS and MCS scores, while controlling for covariates. RESULTS: A lower PCS score was observed in participants with concussion with LOC (B = - 2.65, p = 0.003) compared with those with no history of concussion. Symptoms of PTSD (PCS: B = - 4.84, p < 0.001; MCS: B = - 10.53, p < 0.001) and depression (PCS: B = - 2.85, p < 0.001; MCS: B = - 10.24, p < 0.001) were the strongest statistically significant predictors of lower HRQoL. CONCLUSION: Concussion with LOC was significantly associated with lower HRQoL in the physical domain. These findings affirm that concussion management should integrate physical and psychological care to improve long-term HRQoL and warrant a more detailed examination of causal and mediating mechanisms. Future research should continue to incorporate patient-reported outcomes and long-term follow-up of military service members to further define the lifelong impact of deployment-related concussion.

Research Letter: Prevalence of Spine Injuries Among US Military Personnel With Combat-Related Concussion.

OBJECTIVE: To describe the prevalence of spine injuries among US service members with combat-related concussion. DESIGN AND PARTICIPANTS: A retrospective review of medical records for US service members injured during combat operations in Iraq and Afghanistan between 2002 and 2020. The study sample included 27 897 service members categorized into 3 groups: concussion with loss of consciousness (LOC, n = 4631), concussion non-LOC ( n = 5533), and non-concussion ( n = 17 333). MAIN MEASURES: Spine injuries were identified by International Classification of Diseases, Ninth Revision, Clinical Modification ( ICD-9-CM ) codes and classified by body region and nature of injury using the Barell injury diagnosis matrix. Differences in prevalence of spine injuries by concussion group were evaluated using χ 2 tests. RESULTS: Spine injuries were most prevalent among service members with concussion LOC (31.1%), followed by concussion non-LOC (18.3%), and non-concussion (10.0%, P < .001). Sprains and strains were the most prevalent spine injury category, with injuries to the cervical, thoracic, and lumbar regions significantly more prevalent in the concussion groups ( P values < .001), particularly individuals with LOC compared with non-concussion. CONCLUSION: The US military personnel with combat-related concussion, especially individuals with LOC, may also have spine injuries. Routine assessment for spine injury is recommended during concussion screening because this may impact clinical management and rehabilitation.

Differences in quality-of-life scores across injury categories by mental health status among injured U.S. military service members and veterans.

PURPOSE: Posttraumatic stress disorder (PTSD) and depression are strong predictors of poor health-related quality of life (HRQOL) among injured U.S. military service members (SMs). Patterns of HRQOL between injury categories and injury categories stratified by mental health (MH) symptoms have not been examined. Among deployment-injured SMs and veterans (n = 4353), we examined HRQOL and screening data for PTSD and/or depression within specific injury categories. METHODS: Participants included those enrolled in the Wounded Warrior Recovery Project with complete data for HRQOL (SF-36) from June 2017 to May 2020. Injuries were categorized using the Barell Injury Diagnosis Matrix (Barell Matrix). Mean physical component summary (PCS) and mental component summary (MCS) scores were calculated for each injury category and stratified by the presence or absence of probable PTSD and/or depression. RESULTS: The average follow-up time that participants were surveyed after injury was 10.7 years. Most participants were male, non-Hispanic White, served in the Army, and enlisted rank. Mechanism of injury for 77% was blast-related. Mean PCS and MCS scores across the entire sample were 43.6 (SD = 10.3) and 39.5 (SD = 13.3), respectively; 50% screened positive for depression and/or PTSD. PCS and MCS scores were significantly lower within each injury category among individuals with probable PTSD and/or depression than those without. CONCLUSION: Among deployment-injured SMs, those with probable PTSD and/or depression reported significantly lower HRQOL within injury categories and HRQOL component (i.e., physical or mental) than those without. Findings are consistent with prior reports showing mental health symptoms to be strongly associated with lower HRQOL and suggest integration of mental health treatment into standard care practices to improve long-term HRQOL.

Relationship Between Tinnitus and Hearing Outcomes Among US Military Personnel After Blast Injury.

OBJECTIVES: To examine the association between tinnitus and hearing outcomes among US military personnel after blast injury, including any hearing loss, low-frequency hearing loss, high-frequency hearing loss, early warning shift, and significant threshold shift. DESIGN: In this retrospective study, the Blast-Related Auditory Injury Database was queried for male military service members who had audiometric data 2 years before and after blast injury between 2004 and 2012 with no history of hearing loss or tinnitus before injury (n = 1693). Tinnitus was defined by diagnostic codes in electronic health records. Multivariable logistic regression examined the association between tinnitus and hearing outcomes, while adjusting for covariates. RESULTS: Overall, 14.2% (n = 241) of the study sample was diagnosed with tinnitus within 2 years after blast injury. The proportions of all examined hearing outcomes were higher among service members with tinnitus than those without ( p < 0.001). In multivariable analysis, service members with tinnitus had higher adjusted odds of any hearing loss (odds ratio [OR] = 1.72, 95% confidence interval [CI] = 1.20-2.47), low-frequency hearing loss (OR = 2.77, 95% CI = 1.80-4.26), high-frequency hearing loss (OR = 2.15, 95% CI = 1.47-3.16), early warning shift (OR = 1.83, 95% CI = 1.36-2.45), and significant threshold shift (OR = 2.15, 95% CI = 1.60-2.89) compared with service members without tinnitus. CONCLUSIONS: The findings of this study demonstrate that tinnitus diagnosed within 2 years after blast injury is associated with the examined hearing outcomes in US military personnel. Service members with blast injury who subsequently experience tinnitus should receive routine audiometric hearing conservation testing and be carefully examined for poor hearing outcomes by an audiologist.

Macrotraumatic Fractures of the Multisegmented Ankle-Foot Complex in Military Tactical Athletes: A Cohort Study.

BACKGROUND: Ankle-foot injuries are common in military personnel and substantially degrade function and force readiness. The purpose of this retrospective cohort study was to assess the incidence and contributing factors of traumatic ankle-foot fractures in the US military. METHODS: A population-based study of all service members in the US military was performed assessing the factors of sex, occupation, service branch, rank, and year on segmental tibia-fibula, rearfoot, and forefoot fracture incidence between 2006 and 2015. The Defense Medical Epidemiology Database was queried for the number of individuals with fractures of the tibia-fibula, rearfoot, and forefoot using International Classification of Diseases, Ninth Revision, Clinical Modification on the initial medical encounter. Unadjusted relative risk (RR) calculations were performed assessing sex and occupation. A negative binomial regression assessed the adjusted factors of sex, branch, rank, and year. RESULTS: During this study, 95,540 enlisted service members (8.4 per 1,000 person-years) and 13,318 military officers (5.8 per 1,000 person-years) were diagnosed with ankle-foot fractures. In the adjusted analysis, sex was found to only be a significant factor in forefoot fractures (RR, 1.54), with female service members having a significantly higher risk. There were no significant sex-related differences observed in tibia-fibula or rearfoot fractures. US Navy and Air Force personnel had significantly lower risk of tibia-fibula fractures (RR range, 0.76-0.84) compared with the US Army. Forefoot fracture risk was significantly higher in the US Marine Corps (RR, 1.47) compared with the US Army. Officers had consistently lower risk for fractures in each segment (RR range, 0.68-0.77) compared with enlisted personnel. Enlisted engineers, aviation, and artillery/gunnery compared to infantry, and ground/naval gunfire officers had the greatest relative risk compared all other officer fields (RR range, 1.11-3.67). CONCLUSIONS: Sex, occupation, branch, and rank were salient factors for macrotraumatic ankle-foot fractures. These findings can be used to inform and increase precision in medical planning and in the targeted development of preventive interventions.

Factors Associated With Neuromusculoskeletal Injury and Disability in Navy and Marine Corps Personnel.

INTRODUCTION: Neuromusculoskeletal injuries (NMSKI) are very common in the military, which contribute to short- and long-term disability. MATERIALS AND METHODS: Population-level NMSKI, limited duty (LIMDU), and long-term disability episode counts in the U.S. Navy (USN) and U.S. Marine Corps (USMC) from December 2016 to August 2021 were extracted from the Musculoskeletal Naval Epidemiological Surveillance Tool. The incidence of NMSKI, LIMDU, and long-term disability was calculated. A hurdle negative binomial regression evaluated the association of body region, sex, age, rank, age by rank, and service branch on NMSKI, LIMDU, and long-term disability incidence. RESULTS: From December 2016 to August 2021, there were 2,004,196 NMSKI episodes (USN: 3,285/1,000 Sailors; USMC: 4,418/1,000 Marines), 16,791 LIMDU episodes (USN: 32/1,000 Sailors; USMC: 29/1,000 Marines), and 2,783 long-term disability episodes (USN: 5/1,000 Sailors; USMC: 5/1,000 Marines). There was a large-magnitude protective effect on NMSKI during the pandemic (relative risk, USN: 0.70; USMC: 0.75). Low back and ankle-foot were the most common, primarily affecting female personnel, aged 25-44 years, senior enlisted, in the USMC. Shoulder, arm, pelvis-hip, and knee conditions had the greatest rates of disability, with female sex, enlisted ranks, aged 18-24 years, and service in the USMC having the most salient risk factors. CONCLUSION: Body region, sex, age, rank, and branch were the salient factors for NMSKI. The significant protective effect during the pandemic was likely a function of reduced physical exposure and limited access to nonurgent care. Geographically accessible specialized care, aligned with communities with the greatest risk, is needed for timely NMSKI prevention, assessment, and treatment.

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.

The Neuromusculoskeletal Epidemiological Outcome (NEO) matrix: An innovative injury classification based on anatomical location and primary tissue type.

INTRODUCTION: The purpose of this paper is to propose the Neuromusculoskeletal Epidemiological Outcome (NEO) Matrix, an injury classification based on anatomical location and primary tissue type to classify NMSKI of the trunk and extremities in orthopaedic and sports medicine epidemiological research. MATERIALS AND METHODS: In the proposed NEO matrix, NMSKI diagnosis (International Classification of Disease) codes are classified by the anatomical complex affected. These regional anatomical complexes are frequently employed in orthopaedic and sports medicine disciplines in biomechanical and clinical research. The complexes are arranged from distal to proximal in the lower extremity, inferior to superior in the trunk and head, and proximal to distal in the upper extremity. Injuries are characterized by the primary tissue type affected (Osseous; Articular; Musculotendinous; Neural; Non-specific) based on classified using International Classification of Disease codes. DISCUSSION: The expected patterns of impairment and healing rates of bone, cartilage, ligaments, muscles, tendons, and neural structures vary considerably by the tissue type based on the differences in function, perfusion, and metabolic physiology. Using knowledge of the function of the tissues, expected minimum healing times, and expected sequelae of residual body system impairments, an estimation of morbidity and expected recovery times can be made. While heterogeneity is certainly expected due to varying pathomechanics involved and intrinsic and environmental factors, the NEO matrix classifies the ICD diagnosis codes in framework that qualifies the expected patterns of impairment based on the body system type. CONCLUSION: The NEO matrix provides an alternative approach for characterizing NMSKI in epidemiological research.

Combat injury profiles among U.S. military personnel who survived serious wounds in Iraq and Afghanistan: A latent class analysis.

BACKGROUND: The U.S. military conflicts in Iraq and Afghanistan had the most casualties since Vietnam with more than 53,000 wounded in action. Novel injury mechanisms, such as improvised explosive devices, and higher rates of survivability compared with previous wars led to a new pattern of combat injuries. The purpose of the present study was to use latent class analysis (LCA) to identify combat injury profiles among U.S. military personnel who survived serious wounds. METHODS: A total of 5,227 combat casualty events with an Injury Severity Score (ISS) of 9 or greater that occurred in Iraq and Afghanistan from December 2002 to July 2019 were identified from the Expeditionary Medical Encounter Database for analysis. The Barell Injury Diagnosis Matrix was used to classify injuries into binary variables by site and type of injury. LCA was employed to identify injury profiles that accounted for co-occurring injuries. Injury profiles were described and compared by demographic, operational, and injury-specific variables. RESULTS: Seven injury profiles were identified and defined as: (1) open wounds (18.8%), (2) Type 1 traumatic brain injury (TBI)/facial injuries (14.2%), (3) disseminated injuries (6.8%), (4) Type 2 TBI (15.4%), (5) lower extremity injuries (19.8%), (6) burns (7.4%), and (7) chest and/or abdominal injuries (17.7%). Profiles differed by service branch, combat location, year of injury, injury mechanism, combat posture at the time of injury, and ISS. CONCLUSION: LCA identified seven distinct and interpretable injury profiles among U.S. military personnel who survived serious combat injuries in Iraq or Afghanistan. These findings may be of interest to military medical planners as resource needs are evaluated and projected for future conflicts, and medical professionals involved in the rehabilitation of wounded service members.

Is Prehospital Ketamine Associated With a Change in the Prognosis of PTSD?

INTRODUCTION: Ketamine is an alternative to opioids for prehospital analgesia following serious combat injury. Limited research has examined prehospital ketamine use, associated injuries including traumatic brain injury (TBI) and PTSD outcomes following serious combat injury. MATERIALS AND METHODS: We randomly selected 398 U.S. service members from the Expeditionary Medical Encounter Database who sustained serious combat injuries in Iraq and Afghanistan, 2010-2013. Of these 398 patients, 213 individuals had charted prehospital medications. Clinicians reviewed casualty records to identify injuries and all medications administered. Outcomes were PTSD diagnoses during the first year and during the first 2 years postinjury extracted from military health databases. We compared PTSD outcomes for patients treated with either (a) prehospital ketamine (with or without opioids) or (b) prehospital opioids (without ketamine). RESULTS: Fewer patients received prehospital ketamine (26%, 56 of 213) than only prehospital opioids (69%, 146 of 213) (5%, 11 of 213 received neither ketamine nor opioids). The ketamine group averaged significantly more moderate-to-serious injuries, particularly lower limb amputations and open wounds, compared with the opioid group (Ps < .05). Multivariable regressions showed a significant interaction between prehospital ketamine (versus opioids) and TBI on first-year PTSD (P = .027). In subsequent comparisons, the prehospital ketamine group had significantly lower odds of first-year PTSD (OR = 0.08, 95% CI [0.01, 0.71], P = .023) versus prehospital opioids only among patients who did not sustain TBI. We also report results from separate analyses of PTSD outcomes among patients treated with different prehospital opioids only (without ketamine), either morphine or fentanyl. CONCLUSIONS: The present results showed that patients treated with prehospital ketamine had significantly lower odds of PTSD during the first year postinjury only among patients who did not sustain TBI. These findings can inform combat casualty care guidelines for use of prehospital ketamine and opioid analgesics following serious combat injury.

Sex Differences in the Incidence and Risk of Ankle-Foot Complex Stress Fractures Among U.S. Military Personnel.

Background: The objective of this study was to evaluate sex differences in the incidence and risk of ankle-foot complex (AFC) stress fractures among U.S. military personnel, which could assist in developing management strategies as females assume a greater role in U.S. military operations. Materials and Methods: The Defense Medical Epidemiology Database was used to identify all diagnosed AFC stress fractures in military personnel from 2006 to 2015. Cumulative incidence of AFC stress fractures was calculated and compared by year, service branch, and military rank. Sex differences in the risk of AFC stress fractures by occupation were examined, and integrated (i.e., male and female) occupations were compared with nonintegrated (i.e., male only) occupations. Results: A total of 43,990 AFC stress fractures were identified. The overall incidence rate was 2.76 per 1,000 person-years (p-y) for males and 5.78 per 1,000 p-y for females. Females consistently had higher incidence of AFC stress fractures across all subgroups, particularly among enlisted personnel. Female enlisted service members had the highest risk of AFC stress fractures in aviation (relative risk [RR] = 5.74; 95% confidence interval [CI]: 4.80-6.87) and artillery/gunnery (RR = 5.15; 95% CI: 4.62-5.75) occupations. Females in integrated occupations had significantly higher rates of AFC stress fractures than males in both integrated and nonintegrated occupations (i.e., special forces, infantry, and mechanized/armor). Conclusions: Females in the U.S. military have a higher risk of AFC stress fractures than males. As integration of females into previously sex-restricted occupations continues, focused prevention efforts may be needed to reduce injury burden and maximize medical readiness.

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.

Trajectory of self-rated health after combat-related injury.

BACKGROUND: The U.S. military conflicts in Iraq and Afghanistan yielded the most combat casualties since Vietnam. With more service members than ever surviving their wounds, prospective research on factors related to long-term, patient-reported outcomes, including self-rated health (SRH), has increased importance. This study's objective was to use preinjury and postinjury SRH measures to identify trajectories and predictors of SRH after combat-related injury. METHODS: The Wounded Warrior Recovery Project was queried for U.S. military personnel with combat-related injuries from Iraq or Afghanistan between 2004 and 2011. A single-item measure was used to assess SRH once prior to injury and twice after injury, and responses included excellent, very good, good, fair, or poor. Only those with good or better preinjury SRH levels were included. SRH trajectories were identified and defined. Multinomial logistic regression examined the association between injury-specific characteristics, post-traumatic stress disorder (PTSD), and SRH trajectory. RESULTS: The study sample included 1,093 military personnel. Overall, 4 SRH trajectories were identified: (1) 56.7% resilient (preinjury SRH level was maintained throughout follow-up), (2) 9.4% recovered (SRH declined on first postinjury measure then returned to preinjury level), (3) 22.9% delayed (SRH declined only on second postinjury measure), and (4) 11.0% chronic (SRH declined on first postinjury measure and did not return to preinjury level). In multinomial logistic regression and relative to the resilient group, screening PTSD positive, serious-severe injury severity, and lower extremity injury predicted membership in the recovered and chronic groups, whereas back injury predicted membership in the chronic group only. CONCLUSION: This is the first study to examine long-term SRH trajectory following combat-related injury, finding that a majority of military personnel remain at their preinjury health levels of good or better. Decreases in postinjury SRH were associated with physical and psychological factors, which reinforces the need for a multidisciplinary approach to care.

Time Since Injury as a Factor in Post-Concussion Symptom Reporting among Military Service Members with Blast-Related Concussion.

Over the last decade, much research has been devoted to concussion among military personnel. Post-concussion symptoms after blast-related concussion are common, but it is unknown whether symptom reporting differs over time. This study's objective was to assess the relationship between time since injury and post-concussion symptom reporting. We conducted a retrospective review of existing records to identify service members who experienced blast-related concussion during deployment between 2007 and 2012 and who responded to a Post-Deployment Health Assessment (PDHA). The study population included 3690 military personnel grouped by time between injury and PDHA completion: 1-90 days (45.3%, n = 1,673), 91-180 days (33.0%, n = 1,216), or 181-365 days (21.7%, n = 801). Post-concussion symptoms assessed on the PDHA included headache, tinnitus, memory problems, concentration problems, difficulty making decisions, irritability, dizziness, and sleep problems. All post-concussion symptoms were higher for 91-180 days and 181-365 days after injury relative to 1-90 days, with the exception of dizziness. After adjustment for loss of consciousness, mental health comorbidity, and other covariates, the odds of reporting three or more post-concussion symptoms were significantly higher in those who completed the PDHA 91-180 days (odds ratio: 1.29; 95% confidence interval: 1.09-1.51) or 181-365 days after injury (odds ratio: 1.33; 95% confidence interval: 1.09-1.61), compared with the 1-90 days group. These findings suggest that refinements to in-theater medical care may be needed to reduce post-concussion symptom burden and improve the prospect of concussion recovery.