Does computed tomography-based muscle density predict muscle function and health-related quality of life in patients with idiopathic inflammatory myopathies?

The impact of pain on daily activities in patients with idiopathic inflammatory myopathies: Report from the OMERACT myositis working group

BACKGROUND

International focus groups with patients with idiopathic inflammatory myopathies (IIM) conducted by the OMERACT Myositis Working Group over the years demonstrated the pain as an important symptom experienced by these patients. In this study, we aimed to examine the frequency and degree of pain interference, the aspects of daily life impacted by pain, and the factors associated with pain interference in adults with IIM.

METHODS

This was a prospective observational study with two visits. The patients who fulfilled the probable/definite IIM (ACR/EULAR Myositis Classification Criteria) were enrolled. Pain interference was assessed with PROMIS pain interference form (6a). Myositis core set measures and PROMIS fatigue (7a) and physical function (8b) were obtained at both visits. Logistic regression and linear mixed models were performed to assess the association between pain interference and other parameters.

RESULTS

A total of 129 patients with IIM (60 % females) were recruited from U.S., South Korea, Netherlands, Sweden, and Australia. Approximately 71 % reported pain interference. The patients in the greater pain interference group were more likely to be female, had significantly worse patient/physician global disease activity, fatigue, and physical function than those in the lower pain interference group. The most commonly impacted life aspect was household chores. Manual muscle testing, patient/physician global disease activity, fatigue, and physical function were all significantly associated with pain interference score >60.

CONCLUSION

The majority of the patients with IIM experience the impact of pain on their daily activities, particularly household chores. Myositis disease activity, duration, and subtype could be associated with greater pain interference.

Pain in autoimmune inflammatory myopathies: a scoping review

BACKGROUND

Pain is considered a priority for research by adult patients with autoimmune inflammatory myopathy (AIM) and their families. Our aim was to review the literature for studies reporting on pain in adult AIM and to summarise their findings.

METHODS

A scoping review was conducted searching for studies in PubMed and MEDLINE including more than five adult patients with AIM and assessing pain using a patient-reported outcome measure. Study population characteristics, pain measurement and clinical correlates of pain were extracted using a standardised protocol.

RESULTS

The search strategy identified 2831 studies with 33 meeting inclusion criteria. Most studies used visual analogue scales (n=14) and/or the Medical Outcomes Study 36-Item Short Form Bodily Pain Scale (n=17). Frequency of pain and/or myalgias ranged from 64% to 100%. Subjects with AIM had significantly more pain than the general population and comparable pain to other chronic rheumatic diseases. Insufficient results were available to identify significant clinical correlates of pain in AIM.

CONCLUSION

This review suggests that the burden of pain in AIM is considerable. Still, due to the heterogeneity and low quality of the evidence, significant knowledge gaps persist. Studies are needed to characterise pain trajectories of patients with AIM.

Upper Quadrant Pain and Disability Associated with a Cross-Sectional Area of Deep and Superficial Neck Muscles: A Computed Tomography Study

STUDY DESIGN

An analytical cross-sectional computed tomography (CT) study.

OBJECTIVE

To investigate the association of the cross-sectional area (CSA) and density of neck muscles (sternocleidomastoid, upper trapezius, levator scapulae, anterior scalene, longus coli, longus capitis) with upper quadrant pain and disability.

SUMMARY OF BACKGROUND DATA

Neck pain, a common condition, causes substantial disability to individuals. The deep cervical flexor muscles are impaired in persons with neck pain. These muscles play a greater role in maintaining stable head postures, whereas, superficial muscles are responsible for peak exertions and reinforcing spinal stability at terminal head postures.

METHODS

Two hundred thirty consecutive individuals suffering from neck pain were referred to CT scans; 124/230 complied with the inclusion and exclusion criteria. Subjects were interviewed and the measurements of the CSA and muscle density were extracted from the scans.

RESULTS

Muscles associated with quick disability of the arms, shoulders, and hand questionnaire (QDASH) were the lateral posterior group (LPG) CSA C3-C4 on the right side (beta = -0.31, P = 0.029); the sternocleidomastoid (SCM) CSA C3-C4 on the left side (beta = 0.29, P = 0.031); the LPG CSA C3-C4 on the left side (beta = -0.49, P = 0.000); the LCM CSA C5-C6 on the right side (beta = -0.19, P = 0.049); the LPG CSA C5-C6 on the right side (beta = -0.36, P = 0.012); and the LPG CSA C5-C6 on the left side (beta = -0.42, P = 0.002). Further analyses with radiculopathy acting as an augmenting/enhancing variable (moderator), showed an increase in the model strength (r2 = 0.25) with a stronger prediction of pain and disability. Muscle measurements did not predict neck disability index (NDI) scores.

CONCLUSION

By using an accurate measuring tool, we found an association of the deep and superficial neck muscles' CSA with upper extremities' pain and disability. When performing manual work, a special load is placed on the shoulders and neck muscles. Future research should focus on examining the effectiveness of exercise-type intervention programs to strengthen the deep neck and upper extremities' muscles in order to prevent muscle fatigue.Level of Evidence: 2.

Assessment of Physical Activity and Muscle Function in Adult Inflammatory Myopathies

PURPOSE OF REVIEW

The aim is to summarize the outcome measures used in the assessment and monitoring of muscle function and physical activity in the management idiopathic inflammatory myopathy.

RECENT FINDINGS

Assessment techniques have progressed and matured over the past decade, and new options are now available to clinicians working in this field. Newer outcome measures, including the Functional Index-3 and wearable motion sensors are reviewed, as well as the current application of more established measures. The available outcome measures for use in clinical practice in idiopathic inflammatory myopathies with regard to muscle function and physical activity have expanded over the past 15 years. There are valid and reliable options for several domains and methods for assessing these factors. In a busy clinical setting, efficiency is important, but there also needs to be considered the choosing of tools that work together to give the fullest picture of the status of the patient.

Body composition in longstanding juvenile dermatomyositis; Associations with disease activity, muscle strength and cardiometabolic measures

OBJECTIVE

To (i) compare body composition parameters in patients with longstanding juvenile dermatomyositis (JDM) and controls and (ii) explore associations between body composition and disease activity/inflammation, muscle strength, health-related quality of life (HRQL) and cardiometabolic measures.

METHODS

In a cross-sectional study, we included 59 patients (median disease duration 16.7 y; median age 21.5 y) and 59 age- and sex-matched controls. Active/inactive disease were defined by the PRINTO criteria. Body composition was assessed by total body dual-energy absorptiometry (DXA), inflammation by hs-CRP and cytokines, muscle strength by manual muscle test (MMT-8), HRQL by 36-item short form survey physical component score (SF-36 PCS) and cardiometabolic function by echocardiography (systolic and diastolic function) and serum-lipids.

RESULTS

DXA analyses revealed lower appendicular lean mass index (ALMI) (reflecting limb skeletal muscle mass), higher body fat percentage (BF%) and higher android: gynoid fat ratio (A: G ratio) (reflecting central fat distribution) in patients than controls, despite similar BMI. Patients with active disease had lower ALMI and higher BF% than those with inactive disease; lower ALMI and higher BF% were associated with inflammation (elevated monocyte attractant protein-1 (MCP-1) and hs-CRP). Lower ALMI was associated with reduced muscle strength; higher BF% was associated with impaired HRQL. Central fat distribution (higher A: G ratio) was associated with impaired cardiac function and unfavorable serum-lipids.

CONCLUSION

: Despite normal BMI, patients with JDM, especially those with active disease, had unfavorable body composition, which was associated with impaired HRQL/muscle strength and cardiometabolic function. The association between central fat distribution and cardiometabolic alterations is a novel finding in JDM.

Contribution of Intramyocellular Lipids to Decreased Computed Tomography Muscle Density With Age

Skeletal muscle density, as determined by computed tomography (CT), has been shown to decline with age, resulting in increased frailty and morbidity. However, the mechanism underlying this decrease in muscle density remains elusive. We sought to investigate the role of intramyocellular lipid (IMCL) accumulation in the age-related decline in muscle density. Muscle density was measured using computerized tomography (CT), and IMCL content was quantified using in vivo proton magnetic resonance spectroscopy (¹H-MRS). The study population consisted of 314 healthy participants (142 men, 32–98 years) of the Baltimore Longitudinal Study of Aging (BLSA). In addition to IMCL quantification, obesity-related covariates were measured, including body mass index (BMI), waist circumference, and circulating triglyceride concentration. Higher IMCL concentrations were significantly correlated with lower muscle density in older individuals, independent of age, sex, race, and the obesity-associated covariates (p < 0.01). Lower muscle density was also significantly associated with greater age-adjusted IMCL, a variable we constructed using LOESS regression (p < 0.05). Our results suggest that the accumulation of IMCL may be associated with a decrease in muscle density. This may serve to define a potential therapeutic target for treatment of age-associated decreased muscle function.

Associations Between Measures of Physical Activity and Muscle Size and Strength: A Systematic Review

Objective

To determine whether physical activity is associated with lower limb muscle size and strength within the general population.

Data Sources

Six databases were systematically searched from inception using 3 main constructs: lower extremity, muscle volume, and muscle strength.

Study Selection

Studies that measured physical activity (using either objective or subjective measurements), lower limb muscle size, and strength were included. Available discrete group data were standardized using previously published age- and sex-specific normative values prior to analysis.

Data Extraction

The final analysis included 47 studies from an initial yield of 5402 studies. Standardized scores for outcome measures were calculated for 97 discrete groups.

Data Synthesis

As anticipated, lower limb muscle size was positively correlated with lower limb muscle strength (r=0.26, P<.01; n=4812). Objectively measured physical activity (ie, accelerometry, pedometry) (n=1944) was positively correlated with both lower limb muscle size (r=0.30, P<.01; n=1626) and lower limb strength (r=0.24, P<.01; n=1869). However, subjectively measured physical activity (ie, questionnaires) (n=3949) was negatively associated with lower limb muscle size (r=–0.59, P<.01; n=3243) and lower limb muscle strength (r=–0.48, P<. 01; n=3882).

Conclusions

This review identified that objective measures of physical activity are moderately associated with lower limb muscle size and muscle strength and can, therefore, be used to predict muscle changes within the lower limbs associated with exercise-based rehabilitation programs.

Functioning in adult patients with idiopathic inflammatory myopathy: Exploring the role of environmental factors using focus groups

Objective

Health-related quality of life is impaired in idiopathic inflammatory myopathies. This study aimed to identify the main areas of the health-related quality of life environment domain that are affected in patients with myositis.

Methods

A qualitative study was performed using focus groups and applying the International Classification of Functioning, Disability, and Health. Participants were recruited from a cohort of 323 adult inflammatory myopathy patients consulting at a reference center for idiopathic inflammatory myopathy in Spain, selected by the maximum variation strategy, and placed in focus groups with 5 to 7 patients per group. The number of focus groups required was determined by data saturation.

Results

Twenty-five patients distributed in 4 focus groups were interviewed. The verbatim provided 54 categories directly related with environmental factors. Those associated with products or substances for personal consumption (e110), health professionals (e355), health services, systems and policies (e580), products and technology for personal use in daily living (e115), and immediate family (e310) were the ones most frequently reported.

Conclusion

The results of this study led to identification of several environmental factors that affect the health-related quality of life of patients with myositis. Remedial interventions should be designed to address some of these factors.

Associations of muscle lipid content with physical function and resistance training outcomes in older adults: altered responses with metformin

Preserving muscle mass and strength is critical for long-term health and longevity. Age-related muscle lipid accumulation has been shown to be detrimental to muscle health. In healthy older individuals, we sought to determine whether muscle lipid content, determined from computed tomography, is associated with self-reported physical function, laboratory-measured performance, and the response to progressive resistance training (PRT), and how metformin may alter these responses (N = 46 placebo, 48 metformin). Using multiple linear regression models adjusted for confounders in a large cohort, we show that intermuscular adipose tissue (IMAT) was not associated with baseline function or response to PRT, contrary to previous reports. On the other hand, thigh muscle density (TMD), as an indicator of intra- and extramyocellular lipid (IMCL and EMCL), remained strongly and independently positively associated with physical function and performance following adjustment. Baseline TMD was inversely associated with gains in strength, independent of muscle mass. Percent change in TMD was positively associated with improved chair stand and increased type II fiber frequency but was not associated with muscle hypertrophy or overall strength gain following PRT. For the first time, we show that metformin use during PRT blunted density and strength gains by inhibiting fiber type switching primarily in those with low baseline TMD. These results indicate that participants with higher muscle lipid content derive the most performance benefit from PRT. Our results further indicate that muscle density may be as influential as muscle size for strength, physical function, and performance in healthy older adults. ClinicalTrials.gov , NCT02308228, Registered on 25 November 2014.

The product of trunk muscle area and density on the CT image is a good indicator of energy expenditure in patients with or at risk for COPD

Background

Physical inactivity due to cachexia and muscle wasting is well recognized as a sign of poor prognosis in chronic obstructive pulmonary disease (COPD). However, there have been no reports on the relationship between trunk muscle measurements and energy expenditure parameters, such as the total energy expenditure (TEE) and physical activity level (PAL), in COPD. In this study, we investigated the associations of computed tomography (CT)-derived muscle area and density measurements with clinical parameters, including TEE and PAL, in patients with or at risk for COPD, and examined whether these muscle measurements serve as an indicator of TEE and PAL.

Methods

The study population consisted of 36 male patients with (n = 28, stage 1–4) and at risk for (n = 8) COPD aged over 50 years. TEE was measured by the doubly labeled water method, and PAL was calculated as the TEE/basal metabolic rate estimated by the indirect method. The cross-sectional areas and densities of the pectoralis muscles, rectus abdominis muscles, and erector spinae muscles were measured. We evaluated the relationship between these muscle measurements and clinical outcomes, including body composition, lung function, muscle strength, TEE, and PAL.

Results

All the muscle areas were significantly associated with TEE, severity of emphysema, and body composition indices such as body mass index, fat-free mass, and trunk muscle mass. All trunk muscle densities were correlated with PAL. The product of the rectus abdominis muscle area and density showed the highest association with TEE (r = 0.732) and PAL (r = 0.578). Several trunk muscle measurements showed significant correlations with maximal inspiratory and expiratory pressures, indicating their roles in respiration.

Conclusions

CT-derived measurements for trunk muscles are helpful in evaluating physical status and function in patients with or at risk for COPD. Particularly, trunk muscle evaluation may be a useful marker reflecting TEE and PAL.

Effects of atazanavir, darunavir, and raltegravir on fat and muscle among persons living with HIV

BACKGROUND

Antiretroviral therapy (ART) is associated with gain in quantity of fat and muscle, but the impact on quality is less understood. The objective of this study was to compare fat and muscle density among people with HIV (PWH) on stable raltegravir (RAL), atazanavir with ritonavir (ATV/r), or darunavir with ritonavir (DRV/r), and explore implications on muscle function.

METHODS

Participants from the Modena HIV Metabolic Clinic taking RAL, ATV/r, or DRV/r with at least 1 computed tomography (CT) scan were included. CT scans were reanalyzed for area and density of truncal fat and musculature. Multivariate models explored the effect of ART on fat and muscle density.

RESULTS

One hundred six participants were receiving ATV/r, 48 DRV/r, and 141 RAL. In multivariate models (reference ATV/r), only DRV/r was associated with greater subcutaneous (SAT) and visceral adipose tissue (VAT) area, lower lateralis muscle density (more fat), and greater lateralis intermuscular fat area. Compared to ATV/r, RAL was independently associated with less psoas intermuscular fat area. Among all, greater paraspinal muscle density correlated with better physical function. No associations between ART group and physical function were seen among men; DRV/r was associated with stronger grip strength among women.

CONCLUSION

DRV/r was associated with greater fat area and lower density of both fat and muscle, and RAL with less intermuscular psoas fat. Higher density psoas and paraspinal musculature were associated with better physical function, suggesting potential clinical relevance of these findings.

Assessing skeletal muscle radiodensity by computed tomography: An integrative review of the applied methodologies

Low-radiodensity skeletal muscle has been related to the degree of muscle fat infiltration and seems to be associated with worse outcomes. The aim of this study was to summarize the methodologies used to appraise skeletal muscle radiodensity by computed tomography, to describe the terms used in the literature to define muscle radiodensity and to give recommendations for its measurement standardization. An integrative bibliographic review in four databases included studies published until August 2019 in Portuguese, English or Spanish and performed in humans, adults and/or the elderly, of both sex, which investigated skeletal muscle radiodensity through computed tomography (CT) of the region between the third and fifth lumbar vertebrae and evaluated at least two muscular groups. One hundred and seventeen studies were selected. We observed a trend towards selecting all abdominal region muscle. A significant methodological variation in terms of contrast use, selection of skeletal muscle areas, radiodensity ranges delimitation and their cut-off points, as well as the terminologies used, was also found. The methodological differences detected are probably due to the lack of more precise information about the correlation between skeletal muscle radiodensity by CT and its molecular composition, among others. Therefore, until the gaps are addressed in future studies, authors should avoid arbitrary approaches when reporting skeletal muscle radiodensity, especially when it comes to prognosis inference. Studies using both CT and direct methods of muscle composition evaluation are encouraged, to enable the definition and validation of the best approach to classify fat-infiltrated muscle tissue, which will favour the nomenclature uniformization.

Computed tomography-derived area and density of pectoralis muscle associated disease severity and longitudinal changes in chronic obstructive pulmonary disease: a case control study

BACKGROUND

Muscle wasting is associated with prognosis in patients with chronic obstructive pulmonary disease (COPD). The cross-sectional area of skeletal muscles on computed tomography (CT) could serve as a method to evaluate body composition. The present study aimed to determine the ability of CT-derived pectoralis muscle area (PMA) and pectoralis muscle density (PMD) to determine the severity of COPD and change in longitudinal pulmonary function in patients with COPD.

METHODS

A total of 293 participants were enrolled in this study, a whom 222 had undergone at least two spirometry measurements within 3 years after baseline data acquisition. PMA and PMD were measured from a single axial slice of chest CT above the aortic arch at baseline. The emphysema index and bronchial wall thickness were quantitatively assessed in all scans. The generalized linear model was used to determine the correlation between PMA and PMD measurements and pulmonary function.

RESULTS

PMA and PMD were significantly associated with baseline lung function and the severity of emphysema (P < 0.05). Patients with the lowest PMA and PMD exhibited significantly more severe airflow obstruction (β = - 0.06; 95% confidence interval: - 0.09 to - 0.03]. PMA was statistically associated with COPD assessment test (CAT) score (P = 0.033). However, PMD did not exhibit statistically significant correlation with either CAT scores or modified Medical Research Council scores (P > 0.05). Furthermore, neither PMA nor PMD were associated with changes in forced expiratory volume in 1 s over a 3-year periods.

CONCLUSIONS

CT-derived features of the pectoralis muscle may be helpful in predicting disease severity in patients with COPD, but are not necessarily associated with longitudinal changes in lung function.

The relationship between muscle mass and function in cancer cachexia: smoke and mirrors?

PURPOSE OF REVIEW

Randomized clinical trials of cancer cachexia interventions are based on the premise that an increase in the muscle mass of patients is associated with consequent improvements in muscle function, and ultimately, quality of life. However, recent trials that have succeeded in demonstrating increases in lean body mass have been unable to show associated increases in patient physical function. In this review, we examine the potential causes for this lack of association between muscle mass and function in cancer cachexia, paying particular attention to those factors that may be at play when using body composition analysis techniques involving cross-sectional imaging. Moreover, we propose a new population-specific model for the relationship between muscle mass and physical function in patients with cancer cachexia.

RECENT FINDINGS

The ROMANA 1 and 2 trials of anamorelin (a novel ghrelin agonist) and the POWER 1 and 2 trials of enobosarm (a selective androgen receptor modulator) were able to demonstrate improvements in patient lean body mass, but not the functional co-primary endpoints of handgrip strength and stair climb power, respectively. We report similar confirmatory findings in other studies, and describe potential reasons for these observations.

SUMMARY

The relationship between muscle mass and muscle function is complex and unlikely to be linear. Furthermore, the relationship is influenced by the techniques used to assess nutritional endpoints [e.g. computed tomography (CT)]; the nature of the chosen physical function outcome measures; and the sex and severity of the recruited cachectic patients. Such factors need to be considered when designing intervention trials for cancer cachexia with functional endpoints.

Novel insights of disability assessment in adult myositis

PURPOSE OF REVIEW

To review the novel development of standardized clinical outcome measures used in adult patients with idiopathic inflammatory myopathies (IIMs). A further aim was to determine what aspects of IIM are covered by these outcome measures according to the International Classification of Functioning, Disability and Health (ICF).

RECENT FINDINGS

The sporadic inclusion body myositis functional assessment (sIFA) is the first diagnosis-specific patient-driven patient-reported outcome measure. The adult myositis assessment tool (AMAT) is a new outcome measure assessing physical performance. Also, new criteria to assess response to treatment have been presented for both adults and children with IIM. The ICF provides a standardized frame and structure to report outcome, including functional disability. Using this framework, it is evident that there is a lack of validated patient-reported outcome measures to assess disease aspects important to patient, and that no studies have evaluated life-style factors such as physical activity in these patients.

SUMMARY

The sIFA will ensure patient-relevant patient-reported assessment of activity limitations in patients with inclusion body myositis. The AMAT is a partly validated tool that needs to be used in clinical trials for further validation. The response criteria will enhance assessment of individual response to different treatments.

Mediators and Patterns of Muscle Loss in Chronic Systemic Inflammation

Besides its primary function in locomotion, skeletal muscle (SKM), which represents up to half of human's weight, also plays a fundamental homeostatic role. Through the secretion of soluble peptides, or myokines, SKM interacts with major organs involved in metabolic processes. In turn, metabolic cues from these organs are received by muscle cells, which adapt their response accordingly. This is done through an intricate intracellular signaling network characterized by the cross-talking between anabolic and catabolic pathways. A fine regulation of the network is required to protect the organism from an excessive energy expenditure. Systemic inflammation evokes a catabolic reaction in SKM known as sarcopenia. In turn this response comprises several mechanisms, which vary depending on the nature of the insult and its magnitude. In this regard, aging, chronic inflammatory systemic diseases, osteoarthritis and idiopathic inflammatory myopathies can lead to muscle loss. Interestingly, sarcopenia may persist despite remission of chronic inflammation, an issue which warrants further research. The Janus kinase/signal transducer and activator of transcription (JAK/STAT) system stands as a major participant in muscle loss during systemic inflammation, while it is also a well-recognized orchestrator of muscle cell turnover. Herein we summarize current knowledge about models of sarcopenia, their triggers and major mediators and their effect on both protein and cell growth yields. Also, the dual action of the JAK/STAT pathway in muscle mass changes is discussed. We highlight the need to unravel the precise contribution of this system to sarcopenia in order to design targeted therapeutic strategies.

Healthy overweight/obese youth: early osteosarcopenic obesity features

BACKGROUND

Osteosarcopenic obesity was recently described as a variant phenotype of obesity, mainly observed in old age. This nested case-control study was performed to detect the differences in body composition between young, healthy overweight/obese and healthy lean populations of both genders. Our null hypothesis was that except for the fat mass, there would be absence of body composition differences, namely skeletal muscle and bone masses, between the groups.

METHODS

We used an advanced bio-impedance device to determine the body composition and measured circulating CRP (hsCRP) and diurnal salivary cortisol concentrations, as indices of inflammation and chronic stress, respectively. Overall, 2551 subjects aged 18-21 years participated in the study.

RESULTS

The healthy lean group included 1072 participants [900 males (84%) and 172 females (16%)], and the healthy overweight/obese group included 1479 participants [74 males (5%) and 1405 females (95%)]. Healthy overweight/obese participants presented with an increased fat mass (P < 0·001), as expected, but lower muscle (P < 0·001) and bone (P < 0·001) masses than lean controls. These findings were accompanied by increased extracellular water compartments, circulating hsCRP levels and evening salivary cortisol concentrations in the healthy overweight/obese group.

CONCLUSIONS

Our study suggests that 'osteosarcopenic' elements exist even in very young populations. These may represent a 'precursor' or forme fruste of the osteosarcopenic obesity phenotype in young healthy overweight/obese subjects, who may progressively develop osteosarcopenia in its full form at an older age. Our study highlights the significance of body composition analysis in medical practice, improving prevention and alleviating later health-related economic burden.