Intra- and inter-rater reliability and agreement of stimulus electrodiagnostic tests in post-COVID-19 patients.

Background. COVID-19 patients may present sequelae, such as neuromuscular electrophysiological disorders (NED), that can be assessed using the stimulus electrodiagnostic test (SET). However, little is known about the reliability and agreement of the SET in post-COVID-19 patients.Objective. We aimed to verify the intra-inter-rater reliability and agreement of SET measurements in the rectus femoris, vastus medialis, vastus lateralis, tibialis anterior, and gastrocnemius lateralis (GL) in post-COVID-19 participants.Methods. We designed an observational prospective study to evaluate 20 (10 males and 10 females) post-COVID-19 patients, age: 44.95 ± 11.07 years, weight: 87.99 ± 19.08 kg, height: 1.69 ± 0.09 m. Two independent raters took two evaluations using the SET on selected muscles. The intra-class correlation coefficient (ICC) and 95% limits of the agreement defined the quality and magnitude of the measures.Results. For intra-rater reliability, all measurements presented correlations classified as high or very high (ICC: 0.71-1.0). For inter-rater reliability, the rheobase, chronaxie, accommodation, and accommodation index presented high or very high correlations, except for the accommodation index of the GL (ICC = 0.65), which was moderate.Conclusion. The reliability of the SET obtained by independent raters was very high, except for the GL accommodation, which presented moderate ICC. Therefore, the SET is a reliable tool for evaluating NED in post-COVID-19 patients.

Population characteristics, management, and survival outcomes in muscle-invasive urothelial carcinoma undergoing radical resection: the MINOTAUR study.

PURPOSE: To describe the incidence, management, and survival outcomes of patients with muscle-invasive urothelial carcinoma (MIUC) undergoing radical surgery (RS) in France. METHODS: We relied on a non-interventional real-world retrospective study based on French National Hospitalization Database. Adults with MIUC with a first RS between 2015 and 2020 were selected. Subpopulations of patients with RS performed in 2015 and 2019 (pre-COVID-19) were extracted, according to cancer site: muscle-invasive bladder cancer (MIBC) or upper tract urothelial carcinoma (UTUC). Disease-free and overall survival (DFS, OS - Kaplan-Meier) were assessed on the 2015 subpopulation. RESULTS: Between 2015 and 2020, 21,295 MIUC patients underwent a first RS. Of them, 68.9% had MIBC, 28.9% UTUC, and 2.2% both cancers. Apart from fewer men among UTUC (70.2%) than MIBC patients (90.1%), patients' demographic (mean age ~ 73 years) and clinical characteristics were similar whatever the cancer site or year of first RS. In 2019, RS alone was the most frequent treatment, occurring in 72.3% and 92.6% in MIBC and UTUC, respectively. Between 2015 and 2019, neoadjuvant use rate increased from 13.8% to 22.2% in MIBC, and adjuvant use rate increased from 3.7% to 6.3% in UTUC. Finally, median [95% confidence interval] DFS times were 16.0 [14.0-18.0] and 27.0 [23.0-32.0] months among MIBC and UTUC, respectively. CONCLUSION: Among patients with resected MIUC annually, RS alone remained the main treatment. Neoadjuvant and adjuvant use increased between 2015 and 2019. Nonetheless, MIUC remains of poor prognosis, highlighting an unmet medical need, notably among patients at high risk of recurrence.

Are Football Players More Prone to Muscle Injury after COVID-19 Infection? The "Italian Injury Study" during the Serie a Championship.

INTRODUCTION: Football was the first sport to resume competitions after the coronavirus disease 2019 (COVID-19) lockdown and promptly the hypothesis was raised of a potential relationship between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and musculoskeletal injuries in athletes. This study aimed to confirm the association between SARS-CoV-2 infection and muscle strain injury in a large population of elite football players and to investigate if the COVID-19 severity level could affect the risk of injury. METHODS: A retrospective cohort study involving 15 Italian professional male football teams was performed during the Italian Serie A 2020-2021 season. Injuries and SARS-CoV-2 positivity data were collected by team doctors through an online database. RESULTS: Of the 433 included players, we observed 173 SARS-CoV-2 infections and 332 indirect muscle strains. COVID-19 episodes mostly belonged to severity level I and II. The injury risk significantly increased after a COVID-19 event, by 36% (HR = 1.36, CI95% 1.05; 1.77, p-value = 0.02). The injury burden demonstrated an 86% increase (ratio = 1.86, CI95% 1.21; 2.86, p-value = 0.005) in the COVID-19 severity level II/III versus players without a previous SARS-CoV-2 infection, while level I (asymptomatic) patients showed a similar average burden (ratio = 0.92, CI95% 0.54; 1.58, p-value = 0.77). A significantly higher proportion of muscle-tendon junction injuries (40.6% vs. 27.1%, difference = 13.5%, CI95% 0.002%; 26.9%, p-value = 0.047) was found when comparing level II/III versus Non-COVID-19. CONCLUSIONS: This study confirms the correlation between SARS-CoV-2 infection and indirect muscle injuries and highlights how the severity of the infection would represent an additional risk factor.

Novel nutritional strategies to prevent muscle wasting.

PURPOSE OF REVIEW: Muscle wasting in critical illness has proven to be refractory to physical rehabilitation, and to conventional nutritional strategies. This presents one of the central challenges to critical care medicine in the 21st century. Novel strategies are needed that facilitate nutritional interventions, identify patients that will benefit and have measurable, relevant benefits. RECENT FINDINGS: Drug repurposing was demonstrated to be a powerful technique in the coronavirus disease 2019 pandemic, and may have similar applications to address the metabolic derangements of critical illness. Newer biological signatures may aid the application of these techniques and the association between changes in urea:creatinine ratio and the development of skeletal muscle wasting is increasing. A core outcome set for nutrition interventions in critical illness, supported by multiple international societies, was published earlier this year should be adopted by future nutrition trials aiming to attenuate muscle wasting. SUMMARY: The evidence base for the lack of efficacy for conventional nutritional strategies in preventing muscle wasting in critically ill patients continues to grow. Novel strategies such as metabolic modulators, patient level biological signatures of nutritional response and standardized outcome for measurements of efficacy will be central to future research and clinical care of the critically ill patient.

Effect of a home-based inspiratory muscle training programme on functional capacity in postdischarged patients with long COVID: the InsCOVID trial.

BACKGROUND: Fatigue and exercise intolerance are the most common symptoms in patients with long COVID. AIMS: This study aimed to evaluate whether a home-based inspiratory muscle training (IMT) programme improves maximal functional capacity in patients' long COVID after a previous admission due to SARS-CoV-2 pneumonia. METHODS: This study was a single-centre, blinded assessor, randomised controlled trial. Twenty-six patients with long COVID and a previous admission due to SARS-CoV-2 pneumonia were randomly assigned to receive either a 12-week IMT or usual care alone (NCT05279430). The physiotherapist and participants were not blinded. Patients allocated to the IMT arm were instructed to train at home twice daily using a threshold inspiratory muscle trainer and to maintain diaphragmatic breathing during the training session. The usual care arm received no intervention.The primary endpoint was the change in peak oxygen consumption (peakVO2). Secondary endpoints were changes in quality of life (QoL), ventilatory efficiency and chronotropic response during exercise (evaluated by chronotropic index-CIx- formula). We used linear mixed regression analysis for evaluating changes in primary and secondary endpoints. RESULTS: The mean age of the sample and time to first visit after discharge were 50.4±12.2 years and 362±105 days, respectively. A total of 11 (42.3%) were female. At baseline, the mean of peakVO2, ventilatory efficiency and CIx were 18.9±5 mL/kg/min, 29.4±5.2 and 0.64±0.19, respectively. The IMT arm improved their peakVO2 significantly compared with usual care (+Δ 4.46 mL/kg/min, 95% CI 3.10 to 5.81; p<0.001). Similar positive findings were found when evaluating changes for CIx and some QoL dimensions. We did not find significant changes in ventilatory efficiency. CONCLUSION: In long COVID patients with a previous admission due to SARS-CoV-2 pneumonia, IMT was associated with marked improvement in exercise capacity and QoL. TRIAL REGISTRATION NUMBER: NCT05279430.

Impaired pulmonary and muscle function during moderate exercise in female patients recovered from SARS-CoV-2.

This study aimed to assess pulmonary and muscle dysfunction by analyzing the slow component of oxygen uptake (VO2SC), and mechanical and ventilatory efficiency in adult women recovered from the severe acute respiratory syndrome coronavirus type II (SARS-CoV-2) during a constant load test. 32 women (N = 17 patients with SARS-CoV-2; N = 15 control group) performed two cardiopulmonary exercise tests (CPX) on a cycle ergometer. In the first test, the participants performed incremental CPX until extenuation. In the second test the participants performed a 10-min CPX at a constant load intensity (watts) corresponding to the first ventilatory threshold. There was a 48-72 h rest period between the two tests. There was a significant increase in the VO2SC in the patients recovered from SARS-CoV-2 (160.4 ± 60 mL min-1) in comparison with the healthy participants (59.6 ± 65 mL min-1) (P < 0.001). Mechanical efficiency significantly decreased in patients recovered from SARS-CoV-2 compared to the control group (P = 0.04). Ventilatory inefficiency significantly increased in the patients recovered from SARS-CoV-2 compared with the control group (P < 0.001). Adult women recovered from SARS-CoV-2 infection have important pulmonary and muscular dysfunction and fatigue which contributes to increasing the VO2SC and reducing mechanical and ventilatory efficiency during mild-moderate exercise at a constant load.

Acute Muscle Mass Loss Predicts Long-Term Fatigue, Myalgia, and Health Care Costs in COVID-19 Survivors.

OBJECTIVE: We examined the impact of loss of skeletal muscle mass in post-acute sequelae of SARS-CoV-2 infection, hospital readmission rate, self-perception of health, and health care costs in a cohort of COVID-19 survivors. DESIGN: Prospective observational study. SETTING AND PARTICIPANTS: Tertiary Clinical Hospital. Eighty COVID-19 survivors age 59 ± 14 years were prospectively assessed. METHODS: Handgrip strength and vastus lateralis muscle cross-sectional area were evaluated at hospital admission, discharge, and 6 months after discharge. Post-acute sequelae of SARS-CoV-2 were evaluated 6 months after discharge (main outcome). Also, health care costs, hospital readmission rate, and self-perception of health were evaluated 2 and 6 months after hospital discharge. To examine whether the magnitude of muscle mass loss impacts the outcomes, we ranked patients according to relative vastus lateralis muscle cross-sectional area reduction during hospital stay into either "high muscle loss" (-18 ± 11%) or "low muscle loss" (-4 ± 2%) group, based on median values. RESULTS: High muscle loss group showed greater prevalence of fatigue (76% vs 46%, P = .0337) and myalgia (66% vs 36%, P = .0388), and lower muscle mass (-8% vs 3%, P < .0001) than low muscle loss group 6 months after discharge. No between-group difference was observed for hospital readmission and self-perceived health (P > .05). High muscle loss group demonstrated greater total COVID-19-related health care costs 2 ($77,283.87 vs. $3057.14, P = .0223, respectively) and 6 months ($90,001.35 vs $12, 913.27, P = .0210, respectively) after discharge vs low muscle loss group. Muscle mass loss was shown to be a predictor of total COVID-19-related health care costs at 2 (adjusted ß = $10, 070.81, P < .0001) and 6 months after discharge (adjusted ß = $9885.63, P < .0001). CONCLUSIONS AND IMPLICATIONS: COVID-19 survivors experiencing high muscle mass loss during hospital stay fail to fully recover muscle health. In addition, greater muscle loss was associated with a higher frequency of post-acute sequelae of SARS-CoV-2 and greater total COVID-19-related health care costs 2 and 6 months after discharge. Altogether, these data suggest that the loss of muscle mass resulting from COVID-19 hospitalization may incur in an economical burden to health care systems.

COVID-19 as a Potential Cause of Muscle Injuries in Professional Italian Serie A Soccer Players: A Retrospective Observational Study.

The COVID-19 pandemic has shocked the entire planet. The soccer world has also suffered major upheavals, and many professional soccer players have been infected with the virus. The aim of this study was to evaluate the incidence of injuries in Italian Serie A professional soccer players before and during the COVID-19 pandemic. Methods: We evaluated the incidence of muscle injuries between four competitive seasons of the Italian Serie A (2016-2017, 2017-2018, and 2018-2019 pre-COVID-19 vs. 2020/2021 post-COVID-19) in professional soccer players. Results: Significant differences were found in muscular injuries between the post-COVID-19 season and the previous seasons (p < 0.001). The median split of the players' positivity duration was of 15 days. The players' long positivity (PLP) group showed a significant number of muscular injuries compared to the players' short positivity (PSP) group (p < 0.0014, ES = 0.81, Large). The total teams' days of positivity were significantly related to the total team number of muscular injuries (r = 0.86; CI 95% 0.66 to 0.94; p < 0.0001). In conclusion, this data showed that the competitive season post-COVID-19 lockdown has a higher incidence of muscle injuries in Italian Serie A soccer players compared to the pre-pandemic competitive season.

Muscle fatigability and post-acute COVID-19 syndrome: A case study.

The acute phase of COVID-19 has been well studied, however with increasing post-acute COVID-19 syndrome, much is unknown about its long-term effects. A common symptom in both the acute and post-acute phases has been fatigue, assessed predominantly qualitatively. Here we present a case study objectively assessing neuromuscular fatiguability in a young male (27 year, 1.85 m, 78 kg) who continues to experience COVID-19 related fatigue and cognitive dysfunction, including other symptoms, 12+ months post-infection. Prior to infection, he was part of a neuromuscular study forming the basis of our pre-COVID-19 results. The study was repeated 12 months post-COVID-19 infection. Muscle strength, endurance, torque steadiness, voluntary activation, twitch properties, electromyography, and compound muscle action potential were obtained and compared pre- and post-COVID-19. All measurements were done using a dorsiflexion dynamometer in which the participant also was asked to produce a one-minute fatiguing maximal voluntary contraction. Muscle strength, voluntary activation, and fatigability (slope of torque) showed no meaningful differences, suggesting intrinsic neuromuscular properties are not affected. However, torque steadiness was impaired three-fold in the post- compared with pre-COVID-19 test. The participant also reported a higher level of perceived exertion subjectively and a continued complaint of fatigue. These findings indicate that muscle fatiguability in post-acute COVID-19 syndrome may not be a limitation of the muscle and its activation, but a perceptual disconnect caused by cognitive impairments relating to physical efforts. This case report suggests the potential value of larger studies designed to assess these features in post-acute COVID-19 syndrome.

Associations of sport participation, muscle-strengthening exercise and active commuting with self-reported physical fitness in school-aged children.

Background: Numerous studies suggest a positive association between physical activity and physical fitness in schoolchildren. However, little is known about some neglected forms of physical activity and their associations with physical fitness. This study was conducted via a self-reported questionnaire, owing to the COVID-19 pandemic in many regions in China. Purpose: This study explores the associations between participating in sports, muscle-strengthening exercises, and active commuting with self-reported physical fitness assessed by the International Fitness Scale (IFIS). Methods: A total of 3,807 study participants (ages 11-17) from 12 public schools in South-eastern China were recruited, with 2,407 providing valid data on variables for analysis. Study participants were asked to self-report their sociodemographic factors (i.e., sex, grade, age), participation in sports (never, 1-3 times per month, 1-2 times per week, and 3 or more times per week), muscle-strengthening exercise (0-7 days) and active commuting (0-5 days). Generalized linear models were used to explore the associations between sports participation, muscle-strengthening exercise, and active commuting with self-reported physical fitness (comprising general physical fitness, cardiorespiratory fitness, muscular strength, speed and agility, and flexibility). A total of 2,407 children and adolescents with a mean age of 13.82 (±2.1) years were included in the study's final analysis. Results: The study found no significant association between active commuting and physical fitness. Regarding participating in sports and muscle-strengthening exercises, positive, significant associations were found, which showed that a higher frequency of participating in sports and more participation in muscle-strengthening exercises are associated with improved physical fitness. Conclusion: This study offered evidence on the roles of some aspects of physical activity in physical fitness. To promote health in children and adolescents, they should be encouraged to participate in more sports and engage in muscle-strengthening exercises.

Longitudinal study on the progression of muscle status among community-dwelling ambulatory older multiethnic Asians with type 2 diabetes mellitus.

BACKGROUND: Muscle health decline with age, but its deterioration in older persons with type-2 diabetes mellitus (T2DM) over time is not well-established. This study aimed to determine the change in muscle mass, handgrip strength and gait speed over time among community-dwelling ambulatory older multi-ethnic Asian patients with T2DM and their associated factors. METHODS: Among 387 eligible patients aged 60-89 years who were recruited at baseline, 348 (89.9%) were reviewed at a public primary care clinic in Singapore in the subsequent 9 to 34 months. The change in their clinical and functional status, levels of physical activity and muscle status (mass, grip strength and gait speed based on the Asian Working Group for Sarcopenia criteria) were recorded and compared. Their physical activity levels were assessed using the Physical Activity Scale for the Elderly (PASE) and International Physical Activity Questionnaire (IPAQ). Their quality of life was evaluated based on the World Health Organization Quality of Life (WHOQOL) domains. Linear regression analysis was used to identify the factors associated with muscle health change. RESULTS: The study population comprised men (52.9%), Chinese (69.3%), mean age of 68.4 ± SD5.6 years and had at least secondary education (76.4%). Their mean muscle mass significantly decreased by 0.03 ± SD0.06 kg/m2/month, mean handgrip strength by 0.06 ± SD0.26 kg/month and negligible change in gait speed of 0.002 ± SD0.01 m/sec/month. Their mean weight significantly decreased by 0.5 ± SD3.9 kg, waist and hip circumferences by 2.5 ± SD6cm and 3.2 ± SD5.1 cm respectively, with no change in BMI. Linear regression shows significant associations between muscle mass change and education level (ß = 0.36,p = 0.012, 95% CI = 0.08-0.64), BMI (ß = 0.11,p = < 0.001, 95% CI = 0.05-0.17), change in medication class (ß = 0.39,p = < 0.001, 95% CI = 0.06-0.71) and review interval (ß = - 0.003, p < 0.001, 95% CI = -0.004--0.002). Gait speed change was associated with singlehood (ß = - 0.13,p = 0.029, 95% CI = -0.25--0.01) and WHOQOL physical health (ß = 0.01,p = 0.024, 95% CI = 0.00-0.02) domain. No factor was associated with handgrip strength change. CONCLUSIONS: The study population with T2DM showed significant decline in their mean weight, waist and hip circumferences, mean muscle mass and mean grip strength but gait speed was unaffected. Muscle mass change was associated with education level, BMI and length of review interval. Handgrip strength change was not significantly correlated with any factor. Gait speed change was associated with singlehood and physical health.

Ethical Challenges in Staffing: The Importance of Building Moral Muscle.

SUMMARY: Addressing ethics issues in healthcare is essential to living out an organization's mission, vision, and values. In addition to exacerbating existing ethical dilemmas, the COVID-19 pandemic raised many new and complex questions for leaders and their organizations. Ethical issues related to the workforce require a deliberate and comprehensive consideration of values. The case study scenarios presented here demonstrate examples of common ethical staffing challenges that healthcare leaders have faced, notably the allocation of care providers among COVID-19 patients and the balancing of care quality with staff and patient safety. With access to expert resources and a decision-making framework, leaders can build the moral muscle to meet these challenges and reach ethically justifiable resolutions. These staffing issues highlight the need for increased access to ethics resources for organizational leaders, including moral development support and assistance from experts to resolve complex ethical matters.

Effects of 3 months of multi-nutrient supplementation on the immune system and muscle and respiratory function of older adults in aged care (The Pomerium Study): protocol for a randomised controlled trial.

INTRODUCTION: Immunosenescence leads to increased morbidity and mortality associated with viral infections and weaker vaccine responses. This has been well documented for seasonal influenza and the current pandemic with SARS-CoV-2 (COVID-19), which disproportionately impact older adults, particularly those in residential aged care facilities. Inadequate nutrient intakes associated with impaired immunity, respiratory and muscle function are likely to augment the effects of immunosenescence. In this study, we test whether the impact of inadequate nutrition can be reversed using multi-nutrient supplementation, consequently enhancing vaccine responses, reducing the risk of viral infections and improving respiratory and muscle function. METHODS AND ANALYSIS: The Pomerium Study is a 3-month, single-blind, randomised, controlled trial testing the effects of two daily servings of an oral multi-nutrient supplement (330 kcal, 20 g protein, 1.5 g calcium 3-hydroxy-3-methylbutyrate monohydrate (CaHMB), 449 mg calcium, 500 IU vitamin D3 and 25 vitamins and minerals) on the immune system and muscle and respiratory function of older adults in aged care in Melbourne, Australia. 160 older adults (≥75 years old) will be recruited from aged care facilities and randomised to treatment (multi-nutrient supplement) or control (usual care). The primary outcome is a change in T-cell subsets CD8 + and CD28null counts at months 1 and 3. Secondary outcomes measured at baseline and month 3 are multiple markers of immunosenescence (also at 1 month), body composition (bioimpedance), handgrip strength (dynamometer), physical function (short physical performance battery), respiratory function (spirometry) and quality of life (EQ-5D-5L). Incidence and complications of COVID-19 and/or viral infections (ie, hospitalisation, complications or death) will be recorded throughout the trial, including 3 months after supplementation is ceased. ETHICS AND DISSEMINATION: This study was approved by Melbourne Health Human Research Ethics Committee (Ref No. HREC/73985/MH-2021, ERM Ref No. RMH73985, Melbourne Health Site Ref No. 2021.115). Written informed consent will be obtained from participants. Results will be published in peer-reviewed journals and made available to key aged care stakeholders, including providers, residents, and government bodies. TRIAL REGISTRATION NUMBER: ACTRN12621000420842.

Early and Longitudinal Humoral Response to the SARS-CoV-2 mRNA BNT162b2 Vaccine in Healthcare Workers: Significance of BMI, Adipose Tissue and Muscle Mass on Long-Lasting Post-Vaccinal Immunity.

BACKGROUND: This study aimed to investigate the early and longitudinal humoral response in Healthcare Workers (HCWs) after two doses of the BNT162b2 vaccine and to assess the association between metabolic and anthropometric parameters and the humoral response after vaccination. METHODS: The study included 243 fully vaccinated HCWs: 25.50% previously infected with SARS-CoV-2 (with prior history of COVID-19-PH) and 74.40%-uninfected, seronegative before the first vaccination (with no prior history of COVID-19-NPH). IgG antibodies were measured, and sera were collected: prior to the vaccination, 21 days after the first dose, and 14 days and 8 months after the second dose. RESULTS: 21 days after the first dose, 90.95% of individuals were seropositive; 14 days after the second dose, persistent immunity was observed in 99.18% HCWs, 8 months after complete vaccination-in 61.73%. Statistical analysis revealed that HCWs with PH had a greater chance of maintaining a humoral response beyond eight months after vaccination. Increased muscle mass, decreased fat mass, and younger age may positively affect long-term immunity. Smokers have a reduced chance of developing immunity compared to non-smokers. CONCLUSIONS: Fully vaccinated HCWs with PH are more likely to be seropositive than fully inoculated volunteers with NPH.

Cross-sectional area of erector spinae muscles is associated with activities of daily living at discharge in middle- to older-aged patients with coronavirus disease 2019.

OBJECTIVES: Measurement of skeletal muscle wasting using computed tomography (CT) is widely known to be useful in predicting prognosis. Although some reports have been found in patients with coronavirus disease 2019 (COVID-19), few reports have focused on the ability to perform activities of daily living (ADLs). This study retrospectively investigated the relationship between the erector spinae muscle area measured from CT images and ADL at the time of hospital discharge in patients with COVID-19. METHODS: Among patients aged 40 years or older, 271 patients (median age, 65 years; 180/271 male patients) who had CT cross-sectional images of the 12th thoracic vertebral level on admission were included. The Katz index was used to assess ADLs, and patients who were not completely independent were defined as dependent. Multivariable logistic and Poisson regression analyses were applied to examine the relationship between the cross-sectional area of the erector spinae muscles and the onset of ADL dependence at discharge. RESULTS: A total of 75 (27.7%) patients became dependent on ADL at the time of hospital discharge. Decreased erector spinae muscle area was significantly related to dependent ADL at discharge (adjusted odds ratio: 0.886, 95% confidence interval: 0.805-0.975). In addition, the erector spinae muscle area was significantly related to the number of ADL items for which independence was not achieved (adjusted incidence rate ratio: 0.959, P < 0.001). CONCLUSIONS: The cross-sectional area of the erector spinae muscles from the thoracic CT image was associated with the ability to perform basic ADL at hospital discharge.

Muscle dysfunction in the long coronavirus disease 2019 syndrome: Pathogenesis and clinical approach.

In long coronavirus disease 2019 (long COVID-19), involvement of the musculoskeletal system is characterised by the persistence or appearance of symptoms such as fatigue, muscle weakness, myalgia, and decline in physical and functional performance, even at 4 weeks after the onset of acute symptoms of COVID-19. Muscle injury biomarkers are altered during the acute phase of the disease. The cellular damage and hyperinflammatory state induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may contribute to the persistence of symptoms, hypoxaemia, mitochondrial damage, and dysregulation of the renin-angiotensin system. In addition, the occurrence of cerebrovascular diseases, involvement of the peripheral nervous system, and harmful effects of hospitalisation, such as the use of drugs, immobility, and weakness acquired in the intensive care unit, all aggravate muscle damage. Here, we review the multifactorial mechanisms of muscle tissue injury, aggravating conditions, and associated sequelae in long COVID-19.

Sex-specific associations of fat mass and muscle mass with cardiovascular disease risk factors in adults with type 2 diabetes living with overweight and obesity: secondary analysis of the Look AHEAD trial.

BACKGROUND: Distinguishable sex differences exist in fat mass and muscle mass. High fat mass and low muscle mass are independently associated with cardiovascular disease (CVD) risk factors in people living with type 2 diabetes; however, it is unknown if the association between fat mass and CVD risk is modified by muscle mass, or vice versa. This study examined the sex-specific interplay between fat mass and muscle mass on CVD risk factors in adults with type 2 diabetes living with overweight and obesity. METHODS: Dual-energy X-ray absorptiometry (DXA) measures were used to compute fat mass index (FMI) and appendicular muscle mass index (ASMI), and participants were separated into high-fat mass vs. low-fat mass and high-muscle mass vs. low-muscle mass. A two-way analysis of covariance (ANCOVA: high-FMI vs. low-FMI by high-ASMI vs. low-ASMI) was performed on CVD risk factors (i.e., hemoglobin A1C [A1C]; high-density lipoprotein cholesterol; low-density lipoprotein cholesterol; triglycerides; systolic and diastolic blood pressure; cardiorespiratory fitness, depression and health related-quality of life [HR-QoL]) at baseline and following a 1-year intensive lifestyle intervention (ILI) for females and males separately, with a primary focus on the fat mass by muscle mass interaction effects. RESULTS: Data from 1,369 participants (62.7% females) who completed baseline DXA were analyzed. In females, there was a fat mass by muscle mass interaction effect on A1C (p = 0.016) at baseline. Post-hoc analysis showed that, in the low-FMI group, A1C was significantly higher in low-ASMI when compared to high-ASMI (60.3 ± 14.1 vs. 55.5 ± 13.5 mmol/mol, p = 0.023). In the high-FMI group, there was no difference between high-ASMI and low-ASMI (56.4 ± 12.5 vs. 56.5 ± 12.8 mmol/mol, p = 0.610). In males, only high-FMI was associated with higher A1C when compared to low-FMI (57.1 ± 14.4 vs. 54.2 ± 12.0 mmol/mol, p = 0.008) at baseline. Following ILI, there were significant fat mass by muscle mass interaction effects on changes in the mental component of HR-QoL in males. CONCLUSION: Considering that A1C predicts future CVD, strategies to lower A1C may be especially important in females with low fat and low muscle mass living with type 2 diabetes. Our results highlight the complicated and sex-specific contribution of fat mass and muscle mass to CVD risk factors.

Complement in autoimmune inflammatory myopathies, the role of myositis-associated antibodies, COVID-19 associations, and muscle amyloid deposits.

INTRODUCTION: The inflammatory myopathies (IM) have now evolved into distinct subsets requiring clarification about their immunopathogenesis to guide applications of targeted therapies. AREAS COVERED: Immunohistopathologic criteria of IM with a focus on complement, anti-complement therapeutics, and other biologic immunotherapies. The COVID19-triggered muscle autoimmunity along with the correct interpretation of muscle amyloid deposits is discussed. EXPERT OPINION: The IM, unjustifiably referred as idiopathic, comprise Dermatomyositis (DM), Necrotizing Autoimmune Myositis (NAM), Anti-synthetase syndrome-overlap myositis (Anti-SS-OM), and Inclusion-Body-Myositis (IBM). In DM, complement activation with MAC-mediated endomysial microvascular destruction and perifascicular atrophy is the fundamental process, while innate immunity activation factors, INF1 and MxA, sense and secondarily enhance inflammation. Complement participates in muscle fiber necrosis from any cause and may facilitate muscle-fiber necrosis in NAM but seems unlikely that myositis-associated antibodies participate in complement-fixing. Accordingly, anti-complement therapeutics should be prioritized for DM. SARS-CoV-2 can potentially trigger muscle autoimmunity, but systematic studies are needed as the reported autopsy findings are not clinically relevant. In IBM, tiny amyloid deposits within muscle fibers are enhanced by inflammatory mediators contributing to myodegeneration; in contrast, spotty amyloid deposits in the endomysial connective tissue do not represent 'amyloid myopathy' but only have diagnostic value for amyloidosis due to any cause.