Refinement of machine learning arterial waveform models for predicting blood loss in canines.

Introduction: Hemorrhage remains a leading cause of death in civilian and military trauma. Hemorrhages also extend to military working dogs, who can experience injuries similar to those of the humans they work alongside. Unfortunately, current physiological monitoring is often inadequate for early detection of hemorrhage. Here, we evaluate if features extracted from the arterial waveform can allow for early hemorrhage prediction and improved intervention in canines. Methods: In this effort, we extracted more than 1,900 features from an arterial waveform in canine hemorrhage datasets prior to hemorrhage, during hemorrhage, and during a shock hold period. Different features were used as input to decision tree machine learning (ML) model architectures to track three model predictors-total blood loss volume, estimated percent blood loss, and area under the time versus hemorrhaged blood volume curve. Results: ML models were successfully developed for total and estimated percent blood loss, with the total blood loss having a higher correlation coefficient. The area predictors were unsuccessful at being directly predicted by decision tree ML models but could be calculated indirectly from the ML prediction models for blood loss. Overall, the area under the hemorrhage curve had the highest sensitivity for detecting hemorrhage at approximately 4 min after hemorrhage onset, compared to more than 45 min before detection based on mean arterial pressure. Conclusion: ML methods successfully tracked hemorrhage and provided earlier prediction in canines, potentially improving hemorrhage detection and objectifying triage for veterinary medicine. Further, its use can potentially be extended to human use with proper training datasets.

The Effect of Radiological Assessment of Volunteers for French Paratrooper Training: A Five-Year Retrospective Study.

INTRODUCTION: A systematic radiological examination is needed for military airborne troops in order to detect subclinical medical contraindications for airborne training. Many potential recruits are excluded because of scoliosis, kyphosis, or spondylolisthesis. This study aimed to determine whether complementary radiological assessment excludes too many recruits and whether medical standards might be lowered without increasing medical risk to appointees. METHODS: This retrospective, epidemiological, cross-sectional single-center study spanned 5 years at the French paratroopers' initial training center. We analyzed all medical files and full-spine X-ray results of all enlisted troops during this period. Secondary evaluation by an orthopedic surgeon enabled 23 enlisted personnel, deemed medically unacceptable because of X-ray findings, to be given waivers for airborne training. A follow-up review of their 23 files was conducted to determine whether static-line parachute jumps were hazardous to those who were initially declared medically unacceptable. RESULTS: Of the 3,993 full-spine X-rays, 67.5% (2,695) were described as having normal alignment and structure; 21.8% (871) had lateral spinal deviation; and 10.7% (427) had scoliosis. Sixty-six recruits (1.6%) were deemed unfit because of findings that did not meet the standard on the fullspine X-ray: 53 enlisted personnel had scoliosis greater than 15°, and 13 had spondylolisthesis (grade II or III). Of the 23 patients granted waivers, 82.3% with scoliosis (14) and all patients with kyphosis had not declared any back pain after 5 years. CONCLUSION: The findings, supported by a literature review of foreign military data, suggest that spondylolisthesis above grade I and low back pain are more significant than scoliosis and kyphosis for establishing airborne standards.

Military Medical Student Specialty Preferences During the DHA Transition: A Retrospective Analysis.

BACKGROUND: The Military Health System is a unique subsector within the nation's Graduate Medical Education (GME), with a different incentive structure for specialty selection for military medical students compared with their civilian counterparts. Changes by the Defense Health Agency (DHA) in 2017 emphasized a shift in military GME to training "operational" medical specialties. This study sought to gain insight into military medical students' reactions to the 2017 DHA transition by examining whether students continued to select "operational" specialties at similar rates as well as whether students remained satisfied with attending medical school. METHODS: We performed a retrospective analysis of Uniformed Services University (USU) post-match students from 2015 to 2020 using anonymized data from the Association of American Medical Colleges (AAMC) Graduation Questionnaire, separated into pre-DHA (2015-2017) and post-DHA (2018-2020) transition groups. RESULTS: Regarding both intent to practice an operational specialty and satisfaction with choosing medical school, there was no statistically significant difference between the preand post-DHA transition groups. CONCLUSIONS: Whether preor post-DHA transition, USU medical students demonstrated similar preferences for operational specialties as well as similar levels of satisfaction with medical school attendance, suggesting that this transition may not significantly influence medical students' career preferences nor blunt their desire to enter military medicine.

Vascular Repair in Wartime Casualties.

In the third installment of the "Lest We Forget" series, the authors discuss a critical advance-vascular repair, pioneered by Dr. Carl Hughes-in the care of the war-wounded during the Korean War. This article reviews the management of large vessel injuries in wartime, the challenges and advances in military medicine during the Korean War, and the application of these lessons to current practices.

Psychological first aid in operation for military healthcare providers : a study on pre-deployment training.

INTRODUCTION: During operational missions, while the management of physical injuries in the field remains the priority, the identification of operational incapacity of psychological origin is necessary as it is equally crucial for the safety of the individual, the group and the mission. The French Military Health Service has developed a Psychological First Aid Training in Operation (PFATO) course based on relational simulations, for military service members. The aim is to identify the early signs of psychological distress in a comrade and to adopt an adapted and protective attitude. PFATO training is also offered to healthcare providers. METHODS: We conducted a descriptive cross-sectional study using a self-administered online questionnaire which was sent after deployment to all physicians or nurses trained in PFATO between July 2019 and July 2021 (n=80). The main objective of our work was to evaluate the relevance of this awareness training among physicians and nurses and to identify specific complementary expectations in operational psychiatry for this population. RESULTS: We obtained a response rate of 55%. Significantly, 21.62% of participants used PFATO during their last deployment and another 20% observed a team member using PFATO. The circumstances of use as reported by participants included acute stress related to combat, conflict with hierarchy or comrades, and suicidal crisis. Among those who used PFATO, the training helped 87.5% of them to identify signs of psychological distress and 100% of them to assist combatants . All respondents stressed the added value of practical simulations during PFATO education. Moreover, this study also makes it possible to identify adaptations needed to optimize this module for healthcare providers. CONCLUSION: The results suggest the value for healthcare provider of training in first-response psychological care using relational simulation based on the model of raising awareness about PFATO.

Medicalizing Topography: The French Army and Mediterranean Climates, 1760-1860.

This article details how the French army employed medical topography as a tool of military occupation throughout the Mediterranean world from the mid-eighteenth to mid-nineteenth century. It departs from other works by focusing exclusively on medical topography's military applications. Medical topographies charted the connections between health and the environment by observing a location's features, such as soil, air, and water quality, as well as elevation, prevailing winds, common local diseases, sources of potential contagion, and the cleanliness of urban environments. Because a medical-topographic study took time to write and implement, its findings provided little utility during active conflict. Only after the fighting ceased during a campaign could the army make use of a medical topography's findings by taking measures such as draining swamps, relocating hospitals in unhealthy environments, and issuing climate-appropriate gear.

Cet article examine la façon dont l'armée française utilisait la topographie médicale en tant qu'outil d'occupation militaire pendant les dix-huitième et dix-neuvième siècles dans le monde Méditerranéen. Il se détache des autres travaux en se concentrant exclusivement sur les applications militaires de l'étude. Les études topographiques-médicales analysaient des liens entre l'environnement et la santé. Ces études permettaient l'observation minutieuse et l'enregistrement des caractéristiques d'un lieu, comme par exemple : son élévation, les vents dominants, la qualité de terre, d'eaux, et d'air, la propreté des centres urbaines, et des maladies locales ainsi que leurs origines. Parce que ces études exigeaient du temps d'écrire et d'implémenter, elles n'ont pas eu une grande utilité pratique pendant une campagne. Cependant, après la cessation des hostilités, l'armée a mis en pratique les résultats de ces études. Elle a vidé des marais, déménagé des hôpitaux malsains, et distribué du matériel adapté à l'environnement.

BMI changes among U.S. Navy and Marine Corps active-duty service members during the COVID-19 pandemic, 2019-2021.

BACKGROUND: The COVID-19 pandemic disrupted the daily life and routines of Americans across the United States (U.S.), including those of our active-duty service members (ADSMs). Limited movement orders enacted during this time to promote social distancing prohibited access to fitness and dining facilities for ADSMs. This study aims to expand on previous work identifying changes in body mass index (BMI) among U.S. Army service members by identifying changes in body mass index (BMI) among active-duty service members from both the Navy and Marine Corps during the same time period. METHODS: We conducted a retrospective cohort study of active-duty service members from the Navy and Marine Corps using data from the Military Health System Data Repository. BMI was calculated and categorized according to CDC guidelines both before (February 2019 - January 2020) and during the pandemic (September 2020 - June 2021). Women who were pregnant or delivered during and one year prior to the study periods were excluded. Statistical analyses included paired t-tests evaluating mean BMI, percent change, and the Stuart-Maxwell test for marginal homogeneity. RESULTS: We identified 98,330 active-duty Sailors and 55,298 active-duty Marines for inclusion in this study. During the pandemic period the percentage of Sailors with Underweight decreased by 11%, Healthy weight decreased by 11.1%, Overweight increased by 2.1%, and the percentage of Sailors with Obesity increased by 16.5%. During this same time period, Marines with Underweight decreased by 1%, Healthy weight decreased by 16%, Overweight increased by 3.0%, and Marines with Obesity increased by 51%. The largest increases in service members with overweight and obesity observed among both cohorts were among female service members, service members under age 20, and service members with a Junior Enlisted rank. CONCLUSIONS: Significant increases in obesity were observed amongst active-duty United States Navy and Marine Corps service members during DoD pandemic mitigation efforts. Increased rates of obesity likely effected fitness and force readiness. Future interventions should be targeted at younger, Junior-Enlisted Marines and Sailors to promote healthy lifestyles and provide education on nutrition, appropriate exercise, sleep hygiene, and stress management.

Blast-related mild TBI: LIMBIC-CENC focused review with implications commentary.

BACKGROUND: A significant factor for the high prevalence of traumatic brain injury (TBI) among U.S. service members is their exposure to explosive munitions leading to blast-related TBI. Our understanding of the specific clinical effects of mild TBI having a component of blast mechanism remains limited compared to pure blunt mechanisms. OBJECTIVE: The purpose of this review is to provide a synopsis of clinical research findings on the long-term effects of blast-related mild TBI derived to date from the Long-Term Impact of Military-Relevant Brain Injury Consortium - Chronic Effects of Neurotrauma Consortium (LIMBIC-CENC). METHODS: Publications on blast-related mild TBI from LIMBIC-CENC and the LIMBIC-CENC prospective longitudinal study (PLS) cohort were reviewed and their findings summarized. Findings from the broader literature on blast-related mild TBI that evaluate similar outcomes are additionally reviewed for a perspective on the state of the literature. RESULTS: The most consistent and compelling evidence for long-term effects of blast-related TBI is for poorer psychological health, greater healthcare utilization and disability levels, neuroimaging impacts on brain structure and function, and greater headache impact on daily life. To date, evidence for chronic cognitive performance deficits from blast-related mild TBI is limited, but futher research including crucial longitudinal data is needed. CONCLUSION: Commentary is provided on: how LIMBIC-CENC findings assimilate with the broader literature; ongoing research gaps alongside future research needs and priorities; how the scientific community can utilize the LIMBIC-CENC database for independent or collaborative research; and how the evidence from the clinical research should be assimilated into clinical practice.

Creative Arts Therapies in Rehabilitation.

Appreciation for the utility of creative arts therapy in rehabilitation is on the rise. The limitations of conventional approaches to address posttraumatic stress disorder and co-occurring traumatic brain injury is spurring the development and increased use of creative arts therapies, especially in US military health care systems. However, emerging applications of creative arts therapies in rehabilitation extend well beyond posttraumatic stress disorder/traumatic brain injury and military populations to span the continuum of care, from the intensive care unit, postoperative recovery unit, acute inpatient medical and surgical wards, outpatient clinics, and home health, as well as in traditional long-term care and psychiatric settings. Critical steps to more fully integrating creative arts therapies in rehabilitation include the following: (1) incorporation of education about creative arts therapies into the curricula across rehabilitation disciplines; (2) alteration of national and state policies to promote greater inclusion of creative arts therapies as reimbursable treatments for a wide array of clinical diagnoses and conditions; and (3) significant expansion of creative arts therapies' evidence base. This can be achieved by increasing funding levels to encourage rigorously designed and controlled studies to determine the efficacy, populations, diagnoses and conditions, cofactors, and the mechanisms of action of creative arts therapies. The time has come for a concentrated effort from the community of rehabilitation professional associations, advocacy organizations, and practitioners to promote the advancement and inclusion of creative arts therapies into appropriate clinical settings to optimize outcomes for patients.

Operational mental health. . .what practitioners and commanders should know.

BACKGROUND: Mental Health support to military operations is well established as an integral part of military medicine. Unfortunately, Commanders often receive little or no training in how best to use their mental health assets or what their capabilities are. Conversely, members of a Field Mental Health Team frequently have no operational experience and try to merely translate their civilian practice onto the battlefield. AIM: This article describes what mental health professional can, and should do on military deployments and calls for greater training and awareness of both Mental Health professionals and Operational Commanders to foster mutual understanding and use the Field Mental Health Team to best effect. METHOD: The paper drawson the experience of working in a Field Mental Health Team on six operational deployments in Iraq and Afghanistan. RESULTS: Military mental health professionals work mostly in peacetime and this work ill prepares them for the very different type of work required of them on operations. CONCLUSION: More training is required to prepare both practitioners and commanders for the mental health issues that confront them on operational deployments.

A retrospective chart review to assess the impact of alpha-guided transcranial magnetic stimulation on symptoms of PTSD and depression in active-duty special operations service members.

Introduction: Special Operations Forces service members (SOF) are regularly exposed to traumatic and concussive events, increasing the prevalence of symptoms of post-traumatic stress disorder (PTSD) and depression, shortening potential years of service. Methods: This retrospective chart review presents preliminary data on a Human Performance Optimization (HPO) program that provided an average of 30 sessions of individualized alpha frequency repetitive transcranial magnetic stimulation (α-rTMS) to active-duty SOF as to reduce symptoms of PTSD and depression following traumatic brain injury. Scores from the PTSD Checklist for DSM-5, PROMIS Depression short form and Perceived Deficits Questionnaire (PDQ) were reviewed. Results: Significant reductions were noted after the HPO program in all clinical scales with an average 37% decrease in PCL-5 (p<.01), 11.3% reduction in PROMIS depression T-scores (p<.01), and 45.5% reduction in PDQ scales by session 30 (p<.01), with side effects matching those commonly reported in rTMS. Importantly, the average PCL-5 score decreased from 42.9 to 27 by end of the treatment program, which is below the clinical threshold of 33 for presence of PTSD. For those with depression symptoms scores greater than cut off clinical thresholds at baseline, 46% resolved following treatment. Conclusion: This data provides preliminary support for safe application of α-rTMS for symptom reduction in active-duty special operations military personnel.

Combat-related peripheral nerve injuries.

Active-duty service members (ADSM) and military Veterans represent a population with increased occupational risk for nerve injuries sustained both during training operations and wartime. Mechanisms of war-related nerve injuries have evolved over time, from the musket ball-related traumas described by S.W. Mitchell to complex blast injuries and toxic exposures sustained during Middle East conflicts in the 21st century. Commonly encountered nerve injury etiologies in this population currently include compression, direct trauma, nutritional deficits, traumatic limb amputation, toxic chemical exposures, or blast-related injuries. Expeditious identification and comprehensive, interdisciplinary treatment of combat-associated neuropathies, as well as prevention of these injuries whenever possible is critical to reduce chronic morbidity and disability for service members and to maintain a well-prepared military. However, diagnosis of a combat-associated nerve injury may be particularly challenging due to comorbid battlefield injuries or delayed presentation of neuropathy from military toxic exposures. Advances in imaging for nerve injury, including MRI and ultrasound, provide useful tools to compliment EMG in establishing a diagnosis of combat-associated nerve injury, particularly in the setting of anatomic disruption or edema. Surgical techniques can improve pain control or restoration of function. In all cases, comprehensive interdisciplinary rehabilitation provides the best framework for optimization of recovery. Further work is needed to prevent combat-associated nerve injuries and promote nerve recovery following injury.

Congenital lymphatic dysplasia and severe bone disease in a term neonate with a novel homozygous PIEZO1 variant.

We report a patient with nonimmune fetal hydrops and multiple pathologic fractures. RNA analysis revealed a novel PIEZO1 variant. This report is the first to elucidate PIEZO1's role as a critical regulator of bone mass and strength.

A Two-Stage Approach Integrating Provisional Biomaterial-Mediated Stabilization Followed by a Definitive Treatment for Managing Volumetric Muscle Loss Injuries.

Treatment of volumetric muscle loss (VML) faces challenges due to its unique pathobiology and lower priority in severe musculoskeletal injury management. Consequently, a need exists for multi-stage VML treatment strategies to accommodate delayed interventions owing to comorbidity management or prolonged casualty care in combat settings. To this end, polyvinyl alcohol (PVA) was used at concentrations of 5%, 7.5%, and 10% to generate provisional muscle void fillers (MVFs) of varying stiffness values (1.125 kPa, 3.700 kPa, and 7.699 kPa) to stabilize VML injuries as part of a two-stage approach. These were implanted into a rat model for a duration of 4 weeks, then explanted and either left untreated (control) or treated through minced muscle grafting (MMG). Additional benchmarks included acute MMG and unrepaired groups. At the MVF explant, the 7.5% PVA group exhibited superior neuromuscular function compared to the 5% and 10% PVA groups, the least fibrosis, and the largest median myofiber size among all groups at the 12-week endpoint. Despite the 7.5% PVA's superiority amongst the two-stage treatment groups, neuromuscular function was neither improved nor impaired relative to acute treatment benchmarks. This suggests that the future success of a two-stage VML treatment strategy will necessitate a more effective definitive intervention.

Deep learning models for interpretation of point of care ultrasound in military working dogs.

Introduction: Military working dogs (MWDs) are essential for military operations in a wide range of missions. With this pivotal role, MWDs can become casualties requiring specialized veterinary care that may not always be available far forward on the battlefield. Some injuries such as pneumothorax, hemothorax, or abdominal hemorrhage can be diagnosed using point of care ultrasound (POCUS) such as the Global FAST® exam. This presents a unique opportunity for artificial intelligence (AI) to aid in the interpretation of ultrasound images. In this article, deep learning classification neural networks were developed for POCUS assessment in MWDs. Methods: Images were collected in five MWDs under general anesthesia or deep sedation for all scan points in the Global FAST® exam. For representative injuries, a cadaver model was used from which positive and negative injury images were captured. A total of 327 ultrasound clips were captured and split across scan points for training three different AI network architectures: MobileNetV2, DarkNet-19, and ShrapML. Gradient class activation mapping (GradCAM) overlays were generated for representative images to better explain AI predictions. Results: Performance of AI models reached over 82% accuracy for all scan points. The model with the highest performance was trained with the MobileNetV2 network for the cystocolic scan point achieving 99.8% accuracy. Across all trained networks the diaphragmatic hepatorenal scan point had the best overall performance. However, GradCAM overlays showed that the models with highest accuracy, like MobileNetV2, were not always identifying relevant features. Conversely, the GradCAM heatmaps for ShrapML show general agreement with regions most indicative of fluid accumulation. Discussion: Overall, the AI models developed can automate POCUS predictions in MWDs. Preliminarily, ShrapML had the strongest performance and prediction rate paired with accurately tracking fluid accumulation sites, making it the most suitable option for eventual real-time deployment with ultrasound systems. Further integration of this technology with imaging technologies will expand use of POCUS-based triage of MWDs.

The Effect of Critical Task Auto-failure Criteria on Medical Evaluation Methods in the Pararescue Schoolhouse.

BACKGROUND: Medical training and evaluation are important for mission readiness in the pararescue career field. Because evaluation methods are not standardized, evaluation methods must align with training objectives. We propose an alternative evaluation method and discuss relevant factors when designing military medical evaluation metrics. METHODS: We compared two evaluation methods, the traditional checklist (TC) method used in the pararescue apprentice course and an alternative weighted checklist (AWC) method like that used at the U.S. Army static line jumpmaster course. The AWC allows up to two minor errors, while critical task errors result in autofailure. We recorded 168 medical scenarios during two Apprentice course classes and retroactively compared the two evaluation methods. RESULTS: Despite the possibility of auto-failure with the AWC, there was no significant difference between the two evaluation methods, and both showed similar overall pass rates (TC=50% pass, AWC=48.8% pass, p=.41). The two evaluation methods yielded the same result for 147 out of 168 scenarios (87.5%). CONCLUSIONS: The AWC method strongly emphasizes critical tasks without significantly increasing failures. It may provide additional benefits by being more closely aligned with our training objectives while providing quantifiable data for a longitudinal review of student performance.

Rapid Assessment of Tinnitus Complaints with a Modified Version of the Tinnitus and Hearing Survey.

The objective of this project was to establish cutoff scores on the tinnitus subscale of the Tinnitus and Hearing Survey (THS) using a large sample of United States service members (SM) with the end goal of guiding clinical referrals for tinnitus evaluation. A total of 4,589 SM undergoing annual audiometric surveillance were prospectively recruited to complete the THS tinnitus subscale (THS-T). A subset of 1,304 participants also completed the Tinnitus Functional Index (TFI). The original 5-point response scale of the THS (THS-T16) was modified to an 11-point scale (THS-T40) for some participants, to align with the response scale of the TFI. Age, sex, hearing loss, and self-reported tinnitus bother were also recorded. The THS-T was relatively insensitive to hearing, but self-reported bothersome tinnitus was significantly associated with the THS-T40 score. Receiver operating characteristic analysis was used to determine cutoff scores on the THS-T that aligned with recommended cutoff values for clinical intervention on the TFI. A cutoff of 9 on the THS-T40 aligns with a TFI cutoff of 25, indicating a patient may need intervention for tinnitus. A cutoff of 15 aligns with a TFI cutoff of 50, indicating that more aggressive intervention for tinnitus is warranted. The THS-T is a viable tool to identify patients with tinnitus complaints warranting clinical evaluation for use by hearing conservation programs and primary care clinics. The THS-T40 cutoff scores of 9 and 15 provide clinical reference points to guide referrals to audiology.

Livedoid Vasculopathy with Severe Debilitating Neuropathy in a Prior Professional Athlete.

Livedoid vasculopathy (LV) can be a challenging diagnosis with an interesting pathophysiology. LV is an uncommon diagnosis that can be easily mistaken for more common skin conditions, especially in a person of color who may be underrepresented in pathology images used in medical education. LV has an average of five years from initial presentation to diagnosis, possibly due to providers not having it on their differential for lower extremity ulcerations. Prolonged time to diagnosis can potentially lead to life-changing complications. We present a case of a former professional sprinter who became debilitated by neuropathy secondary to complications from LV. He was seen multiple times and had an extensive work-up exploring a broad differential including autoimmune etiologies, hypercoagulable disorders, neuropathies, and other vascular disorders before reaching the diagnosis. This case emphasizes the importance of early diagnosis and treatment with a multidisciplinary team to help prevent the progression of these symptoms. We break down an extensive work-up that involves a multidisciplinary team including dermatology, hematology, neurology, rheumatology, and vascular surgery. This case will also highlight examples of LV in a patient with a dark skin complexion, which can be challenging to find in current literature. We additionally show images that demonstrate many of the classic pathologic findings associated with LV and how those can help lead to the diagnosis along with detailed descriptions of those findings. Classic physical exam findings including atrophic blanche and lower extremity ulcerations are highlighted. We also review LV's history, diagnosis, and treatment to help readers achieve a better understanding of the disease.

Quantitative interferon-gamma releasing assay in predicting tuberculosis in South Korean military: a retrospective cohort study.

OBJECTIVE: The interferon-gamma releasing assay (IGRA) has been widely used to diagnose latent tuberculosis infection (TBI). However, there are limited data on the association between performance in the IGRA and risk of tuberculosis disease (TBD), as well as on the appropriate IGRA threshold for initiating TBI treatment. METHODS: The analysis was performed using the IGRA results in the Korean Military Manpower Administration database (January 2017 to December 2021), and TBD cases reported to the Korean Military Medical Command (January 2017 to June 2023). All Korean candidates for 18-month military service underwent the IGRA in the pre-enlistment examination, and enlistees who tested positive (≥0.35 IU/mL) were advised to receive TBI treatment before enlistment. RESULTS: From 2017 to 2021, 1 647 941 individuals were screened, with 29 574 testing positive for IGRA. Excluding nonenlistees namely individuals with TBD before enlistment, 19 387 individuals were IGRA positive and 1 356 324 IGRA negative. Of the positives, 4351 were excluded due to discontinued or ongoing TBI treatment at or after enlistment. During follow-up of 9219 untreated and 5818 treated positive individuals and 1 356 324 negatives, TBD occurred in 22 of the IGRA-positive individuals (97.5/100 000 person-years [95% CI, 61.1-147.7]), predominantly in the untreated group (18 cases, 130.1/100 000 person-years [95% CI, 77.1-205.7]) compared to the treated group (4 cases, 45.9/100 000 person-years [95% CI 12.5 - 117.4]), whereas 57 cases occurred in the IGRA-negative group (2.8/100 000 person-years [95% CI, 2.2-3.6]). Elevating the cutoff of IGRA from 0.35 IU/mL to 1.33 IU/mL increased positive predictive value (0.2% vs. 0.4%, p 0.03), with insignificant loss of sensitivity (24% vs. 20%, p 0.69) and decreased numbers needing treatment from 790.5 to 415.3. DISCUSSION: Elevated IGRA levels before enlistment are associated with risk of TBD during military service. It is worth considering raising the IGRA threshold for treatment of TBI in cohorts of healthy, young military individuals.