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Background: Heart rate variability (HRV) is a marker of autonomic function. However, the reliability of short‐term HRV measurement in individuals with combat‐related traumatic injury (CRTI) remains undetermined. Methods: An intra‐ and inter‐rater reliability study was conducted using a subsample (n = 35) of British servicemen with CRTI enrolled in the ongoing ADVANCE study. A five‐minute epoch of single‐lead electrocardiogram data collected during spontaneous breathing was used to measure HRV. HRV analyses were independently performed by two examiners using Kubios. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), minimum detectable change (MDC), and coefficient of variance were calculated for linear [root mean square of successive difference (RMSSD), standard deviation of NN interval, low‐frequency, high‐frequency, total power] and nonlinear (SD1‐2, acceleration and deceleration capacities, sample entropy) measures. Bland–Altman %plots were used to assess bias in intra‐ and inter‐rater HRV data. Results: The mean age of participants was 39.3 ± 6.3 years. An excellent ICC score of 0.9998 (95% CI 0.9997, 0.9999) was observed for intra‐rater analyses of RMSSD, and similar excellent ICC scores were seen for all other HRV measures. The inter‐rater reliability analyses produced an excellent ICC score (range 0.97–1.00). Comparatively, frequency‐domain measures produced higher MDC% and SEM% scores than time‐domain and nonlinear measures in both inter‐ and intra‐rater analyses. The Bland–Altman plots revealed relatively higher bias for frequency‐domain and nonlinear measures than time‐domain measures. Conclusion: ECG‐related short‐term HRV measures were reliable in injured servicemen under spontaneous breathing. However, the reliability appeared better with the time‐domain measure than frequency‐domain and nonlinear measures in this sample. [ABSTRACT FROM AUTHOR]

The relationship between acute combat-related traumatic injury (CRTI) to coronary flow reserve (CFR) and subclinical cardiovascular risk have not been examined and was the primary aim of this study. UK combat veterans from the ADVANCE cohort study (UK-Afghanistan War 2003–14) with traumatic limb amputations were compared to injured non-amputees and to a group of uninjured veterans from the same conflict. Subclinical cardiovascular risk measures included fasted blood atherogenic index of plasma (AIP), triglyceride-glucose index (TyG; insulin resistance), the neutrophil-lymphocyte ratio (NLR) and high-sensitivity C-reactive protein (hs-CRP; vascular inflammation), body mass index (BMI) and visceral fat volume (dual-energy X-ray absorptiometry) and 6-min walk distance (6MWD; physical performance). The subendocardial viability ratio (SEVR), to estimate CFR, was calculated using arterial pulse waveform analysis (Vicorder device). In total 1144 adult male combat veterans were investigated, comprising 579 injured (161 amputees, 418 non-amputees) and 565 uninjured men. AIP, TyG, NLR, hs-CRP, BMI, total body fat and visceral fat volume were significantly higher and the SEVR and 6MWD significantly lower in the amputees versus the injured-non-amputees and uninjured groups. The SEVR was lowest in those with above knee and multiple limb amputations. CRTI (ExpB 0.96; 95% CI 0.94–0.98: p < 0.0001) and amputation (ExpB 0.94: 95% CI 0.91–0.97: p < 0.0001) were independently associated with lower SEVR after adjusting for age, rank, ethnicity and time from injury. CRTI, traumatic amputation and its worsening physical deficit are associated with lower coronary flow reserve and heightened subclinical cardiovascular risk. • This is the first study to examine the subendocardial viability ratio (SEVR) as a measure of coronary flow reserve and subclinical cardiovascular risk following combat-related traumatic limb amputation • Markers of systemic inflammation (hs-CRP and neutrophil-lymphocyte ratio), obesity (visceral and total body fat), atherogensis (atherogenic index of plasma [AIP]) and insulin resistance (triglyceride-glucose index [TyG]) were greater whereas as functional status (six-minute walk test) and SEVR lower among injured amputees compared with injured non amputees and uninjured combat veterans exposed to the same conflict. • We found that combat related traumatic amputation and its worsening functional deficit was independently associated with a lower subendocardial viability ratio and coronary flow reserve [ABSTRACT FROM AUTHOR]

Social support is a key determinant of mental health across multiple populations and contexts. Little is known about social support among UK (ex-)military personnel, especially those with combat injuries following deployment to Afghanistan. This study aimed to investigate the level of perceived social support and its associations with mental health among injured and uninjured UK (ex-)military personnel. An analysis of baseline data from the Armed Services Trauma Rehabilitation Outcome (ADVANCE) prospective cohort study was performed. A representative sample of male UK combat-injured personnel was compared with a frequency-matched sample of uninjured personnel. Validated questionnaires were completed including the Multidimensional Scale of Perceived Social Support (MSPSS). MSPSS score was transformed using linear splines with a knot at ≥ 55. Multivariable logistic regression analyses examined associations between perceived social support and mental health. In total, 521 combat-injured participants (137 with amputations) and 515 uninjured participants were included. Median MSPSS score was 65 (interquartile range [IQR] 54–74). Injured and uninjured participants reported similar MSPSS scores, as did those injured with amputations, and non-amputation injured participants. For each one unit increase in MSPSS score (for scores ≥55), the odds of post-traumatic stress disorder decreased (adjusted odds ratio [AOR] 0.93, 95% confidence interval [CI] 0.91 to 0.96). No such association was found with MSPSS scores below 55 (AOR 0.99, 95% CI 0.97 to 1.01). Similar results were observed for depression and anxiety. Perceived social support may be a target for intervention within this population, irrespective of injury status. • Injured/uninjured UK military personnel report similar levels of social support. • Amputation/non-amputation injured personnel report similar levels of social support. • Social support has a negative association with mental health. [ABSTRACT FROM AUTHOR]