Development of Novel Methods to Define Deficits in Appendicular Lean Mass Relative to Fat Mass

Sarcopenic obesity is associated with adverse outcomes after kidney transplantation: a retrospective cohort study

PURPOSE

Sarcopenia was found to be a poor prognostic factor in kidney transplant recipients, but the role of sarcopenia obesity remains unclear. This study aimed to explore the effect of sarcopenic obesity on kidney transplantation.

METHODS

A retrospective analysis was performed on kidney transplant recipients between 2015 and 2019. Pretransplant CT scans were utilized to assess sarcopenia and visceral obesity. Based on the presence or absence of sarcopenia and visceral obesity, the recipients were classified into four distinct groups.

RESULTS

The recipients were categorized into four groups based on their characteristics: the nonsarcopenic nonobesity group (n = 493, 49.85%), the nonsarcopenic obesity group (n = 248, 25.08%), the sarcopenic nonobesity group (n = 188, 19.01%), and the sarcopenic obesity group (n = 60, 6.07%). Multivariate analysis, identified sarcopenic obesity was as an independent risk factor for mortality following kidney transplantation (adjusted hazard ratio, 5.861; 95% confidence interval [CI]: 1.627-21.108; P = 0.007). Additionally, sarcopenic obesity was associated with an increased risk of delayed graft function (adjusted odds ratio [aOR], 3.342; 95% CI 1.421-7.745; P = 0.005), perioperative incision infection (aOR, 9.654; 95% CI 1.572-60.648; P = 0.011), perioperative pulmonary infection (aOR, 2.557; 95% CI 1.208-5.215; P = 0.011), and readmission within 3 months (aOR, 2.100; 95% CI 1.051-4.017; P = 0.029). While sarcopenic obesity was found to be associated with impaired graft renal function, it did not show a significant correlation with death-censored graft survival or quality of life.

CONCLUSION

The presence of sarcopenic obesity prior to kidney transplantation represents an independent risk factor for mortality, and it is also linked to a range of unfavorable outcomes.

Strength training is more effective than aerobic exercise for improving glycaemic control and body composition in people with normal-weight type 2 diabetes: a randomised controlled trial

AIMS/HYPOTHESIS

Type 2 diabetes in people in the healthy weight BMI category (<25 kg/m2), herein defined as 'normal-weight type 2 diabetes', is associated with sarcopenia (low muscle mass). Given this unique body composition, the optimal exercise regimen for this population is unknown.

METHODS

We conducted a parallel-group RCT in individuals with type 2 diabetes (age 18-80 years, HbA1c 47.5-118.56 mmol/mol [6.5-13.0%]) and BMI <25 kg/m2). Participants were recruited in outpatient clinics or through advertisements and randomly assigned to a 9 month exercise programme of strength training alone (ST), aerobic training alone (AER) or both interventions combined (COMB). We used stratified block randomisation with a randomly selected block size. Researchers and caregivers were blinded to participants' treatment group; however, participants themselves were not. Exercise interventions were conducted at community-based fitness centres. The primary outcome was absolute change in HbA1c level within and across the three groups at 3, 6 and 9 months. Secondary outcomes included changes in body composition at 9 months. Per adherence to recommended exercise protocol (PP) analysis included participants who completed at least 50% of the sessions.

RESULTS

Among 186 individuals (ST, n=63; AER, n=58; COMB, n=65) analysed, the median (IQR) age was 59 (53-66) years, 60% were men and 83% were Asian. The mean (SD) HbA1c level at baseline was 59.6 (13.1) mmol/mol (7.6% [1.2%]). In intention-to-treat analysis, the ST group showed a significant decrease in HbA1c levels (mean [95% CI] -0.44 percentage points [-0.78, -0.12], p=0.002), while no significant change was observed in either the COMB group (-0.35 percentage points, p=0.13) or the AER group (-0.24 percentage points, p=0.10). The ST group had a greater improvement in HbA1c levels than the AER group (p=0.01). Appendicular lean mass relative to fat mass increased only in the ST group (p=0.0008), which was an independent predictor of HbA1c change (beta coefficient -7.16, p=0.01). Similar results were observed in PP analysis. Only one adverse event, in the COMB group, was considered to be possibly associated with the exercise intervention.

CONCLUSIONS/INTERPRETATION

In normal-weight type 2 diabetes, strength training was superior to aerobic training alone, while no significant difference was observed between strength training and combination training for HbA1c reduction. Increased lean mass relative to decreased fat mass was an independent predictor of reduction in HbA1c level.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02448498.

FUNDING

This study was funded by the National Institutes of Health (NIH; R01DK081371).

Role of Body Composition in the Prediction of Skeletal Fragility Induced by Hormone Deprivation Therapies in Cancer Patients

PURPOSE OF REVIEW

This review paper is intended to show that changes in body composition are key in the pathogenesis of bone fragility amongst patients with breast and prostate cancer receiving hormone deprivation therapies (HDTs) and that the mechanism is based on the development of alterations in bone quality rather than in bone quantity.

RECENT FINDINGS

Preclinical and clinical data suggest a tight connection amongst bone, adipose and muscular tissues by means of several soluble mediators, potentially leading to (1) bone resorption and bone quality deterioration in sarcopenic obese subjects, (2) bone mineral deposition in healthy trained subjects. Cancer patients treated with HDTs frequently fall into the first condition, named osteosarcopenic obesity. Current clinical guidelines for the prevention of treatment-induced osteoporosis focus on bone mineral density (BMD) as a main predictive factor for fracture risk; however, the pathophysiology underlying HDT-induced bone fragility differs from that of primary and postmenopausal osteoporosis, suggesting a prevalent role for bone quality alterations. Focusing on available data from clinical trials, in our review we suggest osteosarcopenic obesity as a common target for the prevention and treatment of HDTs-related metabolic and skeletal complications, beyond a BMD-centred approach.

Sarcopenia in Immune-Mediated Rheumatic Diseases-Review

INTRODUCTION

Sarcopenia is a condition characterized by decreased muscle strength and muscle mass, which can impact physical function. Sarcopenia develops as a consequence of age-related decline (primary sarcopenia) and has a major impact on physical, social, and emotional well-being. In addition, patients with rheumatic diseases may suffer from sarcopenia independently of aging (secondary sarcopenia). Exercise, pharmacological treatments, and nutritional supplementation are some of the strategies used for the management of sarcopenia in the general population. The aim of this review is to summarize the evidence around the prevalence and impact of sarcopenia in patients with rheumatic diseases.

CONCLUSIONS

From our review, we can state that sarcopenia is a common and prevalent condition among the rheumatic diseases. Furthermore, the impacts of sarcopenia are not well-appreciated, and the implementation of treatment strategies has not been widespread. Strategies such as exercise and some pharmacological treatments are effective in improving physical and functional impairment related to these conditions.

FUTURE RESEARCH DIRECTIONS IN THE FIELD

New pharmacological treatments are being actively studied and may contribute in the future to the management of sarcopenia.

Rheumatoid sarcopenia: loss of skeletal muscle strength and mass in rheumatoid arthritis

Sarcopenia, a disorder that involves the generalized loss of skeletal muscle strength and mass, was formally recognized as a disease by its inclusion in the International Classification of Diseases in 2016. Sarcopenia typically affects older people, but younger individuals with chronic disease are also at risk. The risk of sarcopenia is high (with a prevalence of ≥25%) in individuals with rheumatoid arthritis (RA), and this rheumatoid sarcopenia is associated with increased likelihood of falls, fractures and physical disability, in addition to the burden of joint inflammation and damage. Chronic inflammation mediated by cytokines such as TNF, IL-6 and IFNγ contributes to aberrant muscle homeostasis (for instance, by exacerbating muscle protein breakdown), and results from transcriptomic studies have identified dysfunction of muscle stem cells and metabolism in RA. Progressive resistance exercise is an effective therapy for rheumatoid sarcopenia but it can be challenging or unsuitable for some individuals. The unmet need for anti-sarcopenia pharmacotherapies is great, both for people with RA and for otherwise healthy older adults.

Adipocytokines and Associations With Abnormal Body Composition in Rheumatoid Arthritis

OBJECTIVE

We determined associations between adipokines and abnormal body composition in patients with rheumatoid arthritis (RA).

METHODS

Combining data from three RA cohorts, whole-body dual-energy absorptiometry measures of appendicular lean mass and fat mass indices were converted to age-, sex-, and race- and ethnicity-specific Z scores. Lean mass relative to fat mass was determined based on prior methods. Independent associations between body composition profiles and circulating levels of adiponectin, leptin, and fibroblast growth factor (FGF)-21 were assessed using linear and logistic regression models adjusting for demographic characteristics and study cohort. We also determined the improvement in the area under the curve (AUC) for prediction of low lean mass when adipokines were added to predictive models that included clinical factors such as demographic characteristics, study, and body mass index (BMI).

RESULTS

Among 419 participants, older age was associated with higher levels of all adipokines, whereas higher C-reactive protein level was associated with lower adiponectin levels and higher FGF-21 levels. Greater fat mass was strongly associated with lower adiponectin levels and higher leptin and FGF-21 levels. Higher levels of adiponectin, leptin, and FGF-21 were independently associated with low lean mass. The addition of adiponectin and leptin levels to regression models improved prediction of low lean mass when combined with demographic characteristics, study, and BMI (AUC 0.75 vs. 0.66).

CONCLUSION

Adipokines are associated with both excess adiposity and low lean mass in patients with RA. Improvements in the prediction of body composition abnormalities suggest that laboratory screening could help identify patients with altered body composition who may be at greater risk of adverse outcomes.

Associations Between Low Serum Urate, Body Composition, and Mortality

OBJECTIVE

Controversy remains as to whether low serum urate or uric acid (UA) levels contribute to adverse outcomes. We evaluated the relation between low serum UA levels and sarcopenia and assessed whether sarcopenia confounds associations between these low levels and mortality.

METHODS

We utilized data from the National Health and Nutrition Examination Survey (1999-2006). Participants with available whole-body dual x-ray absorptiometry body composition measurements and serum UA concentrations were included. Body composition assessments included body mass index (BMI), waist circumference, maximum lifetime BMI, and age-, sex-, and race-specific appendicular lean mass index (ALMI) and fat mass index (FMI) Z scores. We also calculated Z scores for ALMI relative to FMI (ALMIFMI ). We evaluated associations between serum UA levels and body composition using logistic regression and assessed associations between serum UA levels and mortality before and after adjusting for differences in body composition using Cox proportional hazards regression.

RESULTS

Among the 13,979 participants, low serum UA concentrations (<2.5 mg/dl in women, <3.5 mg/dl in men) were associated with low lean mass (ALMI and ALMIFMI Z scores), underweight BMI (<18.5 kg/m2 ), and higher rates of weight loss. The proportion of patients with low ALMI Z scores was 29% in the low serum UA group and 16% in the normal serum UA group (P = 0.001). Low serum UA levels were associated with increased mortality before we adjusted for body composition (hazard ratio 1.61 [95% confidence interval 1.14-2.28]; P = 0.008) but was attenuated and not significant after adjustment for body composition and weight loss (hazard ratio 1.30 [95% confidence interval 0.92-1.85], P = 0.13).

CONCLUSION

Sarcopenia and weight loss are more common among patients with low serum UA concentrations. Differences in body composition may help to explain associations between low levels of serum UA and higher mortality.

Relation between adipose tissue and the musculoskeletal unit in a group of postmenopausal women

Introduction

Involutional changes observed during aging increase rapidly in the postmenopausal period. These changes include body composition by affecting bone, muscle and fat tissue. A number of studies have investigated the mutual interaction between bone and muscle tissue, whereas adipose tissue had not been studied thoroughly.The aim of the present study was to assess the relation between fat tissue parameters and the musculoskeletal unit.

Material and methods

The study was conducted in a group of 120 postmenopausal women with an average age of 69 years (59-81; SD 5.3). All women had been asked to complete a questionnaire (medical history) and underwent a total body composition analysis [bone mineral density (BMD)] testing (spine and/or neck) followed by a handgrip test.

Results

The study revealed strong correlations between appendicular skeletal muscle mass index - appen.lean/height², visceral adipose tissue area (VAT) and fat/mass/height² index (r = 0.589 and 0.658 respectively; p < 0.001). The results were not supported by muscle strength (handgrip). The authors identified correlations between the bone parameters and adipose tissue but these were identified as weak or moderate (p < 0.05). Special emphasis should be placed on the relation between the trabecular bone score (TBS) and VAT area (r = -0.385, p < 0.001).

Conclusions

There is a strong dependence between muscle and adipose tissues. Despite the fact that the increase in fat is correlated with the growth of muscle tissue, it is not accompanied by better quality of the muscle (handgrip). Bone microarchitecture is more related to VAT area than neck/spine BMD.

The effect of disease-modifying anti-rheumatic drugs on skeletal muscle mass in rheumatoid arthritis patients: a systematic review with meta-analysis

INTRODUCTION

Rheumatoid arthritis (RA) is an autoimmune disease, characterized by chronic and systemic inflammation. Besides, it is known that RA patients may present several comorbidities, such as sarcopenia, a condition where patients present both muscle mass and muscle quality impairment. RA treatment is mostly pharmacological and consists in controlling systemic inflammation and disease activity. Despite that, the effect of pharmacological treatment on sarcopenia is not well characterized.

OBJECTIVE

To summarize the effects of disease-modifying anti-rheumatic drugs (DMARDs) on skeletal muscle tissue in rheumatoid arthritis (RA) patients.

METHODS

A systematic review of randomized clinical trials and observational studies was conducted using MEDLINE, Embase, Cochrane Library, and Web of Science. We selected studies with rheumatoid arthritis patients treated with disease-modifying anti-rheumatic drugs (DMARDs) that analyzed muscle mass parameters such as lean mass and appendicular lean mass. Methodological quality was assessed using the Newcastle-Ottawa Quality Assessment Scale. Standardized mean difference (SMD) and 95% confidence intervals (CI) were set. A meta-analysis of observational studies was performed using the R software, and we considered significant statistics when p < 0.05.

RESULTS

Nine studies were included in this systematic review. In the meta-analysis, DMARD treatment had no positive difference (p = 0.60) in lean mass. In the same way, in the appendicular lean mass parameter, our results showed that DMARDs did not have changes between baseline and post-treatment analysis (p = 0.93).

CONCLUSION

There is no evidence of a significant effect of DMARD therapy, either synthetic or biological, on muscle mass. However, this association should be investigated with more studies.

Body composition and myokines in a cohort of patients with Becker muscular dystrophy

Introduction/Aims

Becker muscular dystrophy (BMD) is an X‐linked disease leading to muscle wasting and weakness. The decrease in lean body mass (LBM) in Duchenne muscular dystrophy, has shown correlation with loss of muscle function and bone density (BD). Myokines (including irisin) are hormones secreted by skeletal muscle that allow crosstalk between muscle and bone. The present study analyzed body composition and circulating myokine levels in a cohort of BMD patients; moreover, the association between dual energy X‐ray absorptiometry (DXA) parameters, functional motor assessments, and myokine levels was investigated.

Methods

All patients underwent DXA, blood samples for myokine assays, and functional motor assessments. A group of healthy controls (HCs) was also included.

Results

Thirty BMD patients, median age at evaluation 36.0 y [26.0–41.0], were included. Twenty‐nine patients underwent whole‐body DXA. Median value of total body Z‐score was −0.70. The prevalence of low skeletal muscle mass defined as appendicular skeletal muscle mass index (ASMMI) < 7.59 kg/m² was 83%. Irisin levels were significantly lower in BMD compared to HCs (p = .03). All DXA parameters showed significant correlation with the functional motor assessments, in particular the h²‐standardized lean mass lower limb index (p = .0006); h²‐standardized total fat mass showed negative correlations with North Star Ambulatory Assessment and 6 min walk test (p = .03).

Discussion

DXA is a useful tool to evaluate body composition in BMD patients; the decrease in BD and LBM is associated with a reduction of motor function in BMD.

Association of Lean Body Mass and Fat Mass With 1-Year Mortality Among Patients With Heart Failure

Background

Prior studies have found an unexplained inverse or U-shaped relationship between body mass index (BMI) and mortality in heart failure (HF) patients. However, little is known about the independent effects of each body component, i.e., lean body mass (LBM) and fat mass (FM), on mortality.

Methods

We used data from the China Patient-centered Evaluative Assessment of Cardiac Events-Prospective Heart Failure Study. LBM and FM were calculated using equations developed from the National Health and Nutrition Examination Survey. LBM and FM index, calculated by dividing LBM or FM in kilograms by the square of height in meters, were used for analysis. We used restricted cubic spline and Cox model to examine the association of LBM and FM index with 1-year all-cause mortality.

Results

Among 4,305 patients, median (interquartile range) age was 67 (57–76) years, 37.7% were women. During the 1-year follow-up, 691 (16.1%) patients died. After adjustments, LBM index was inversely associated with mortality in a linear way (P-overall association &lt; 0.01; P-non-linearity = 0.52), but no association between FM index and mortality was observed (P-overall association = 0.19). Compared with patients in the 1st quartile of the LBM index, those in the 2nd, 3rd, and 4th quartiles had lower risk of death, with hazard ratio of 0.80 (95% CI 0.66–0.97), 0.65 (95% CI 0.52–0.83), and 0.61 (95% CI 0.45–0.82), respectively. In contrast, this association was not observed between FM index quartiles and mortality.

Conclusion

Higher LBM, not FM, was associated with lower 1-year mortality among HF patients.

Body composition in individuals with cystic fibrosis

•

BMI is used to characterize nutritional status but may not accurately depict body composition in CF.

•

DXA and bioelectrical impedance are the most commonly used methods for assessing BC.

•

Lower fat-free mass associates with worse pulmonary function and greater CF disease severity.

•

Fat-free mass associates with greater bone mineral density in individuals with CF.

Because nutritional status is intimately linked with pulmonary function and survival, nutrition has been at the mainstay of cystic fibrosis (CF) care. Body Mass Index (BMI) is traditionally used to define nutritional status because of the ease with which it can be calculated, but it has a number of limitations including its inability to differentiate fat mass (FM) from lean body mass (LBM), the latter thought to confer health advantage. A number of tools are available to quantify body composition including dual-energy x-ray absorptiometry (DXA), bioelectrical impedance, MRI, CT, air displacement plethysmography, and stable isotopes, and these have been used to varying degrees in studies of CF. In CF, LBM tends to be lower for a given BMI, particularly at lower BMI. In adults, lower fat-free mass (FFM) correlates with greater CF disease severity, lower pulmonary function and higher inflammatory markers. FFM is also positively associated with greater bone mineral density, while greater FM is associated with greater loss of lumbar spine bone mineral density over 2 years. In youth, LBM is positively associated with pulmonary function. The predictive value of body composition for functional and clinical outcomes and the role of improving LBM on these outcomes remain undefined. With improvements in BMI accompanying highly-effective modulator therapy, closer evaluations of body composition may inform risk for more traditional, non-CF adult outcomes in CF.

The effects of resistance training with blood flow restriction on muscle strength, muscle hypertrophy and functionality in patients with osteoarthritis and rheumatoid arthritis: A systematic review with meta-analysis

Introduction

Rheumatoid arthritis(RA) and osteoarthritis(OA) patients showed systemic manifestations that may lead to a reduction in muscle strength, muscle mass and, consequently, to a reduction in functionality. On the other hand, moderate intensity resistance training(MIRT) and high intensity resistance training(HIRT) are able to improve muscle strength and muscle mass in RA and OA without affecting the disease course. However, due to the articular manifestations caused by these diseases, these patients may present intolerance to MIRT or HIRT. Thus, the low intensity resistance training combined with blood flow restriction(LIRTBFR) may be a new training strategy for these populations.

Objective

To perform a systematic review with meta-analysis to verify the effects of LIRTBFR on muscle strength, muscle mass and functionality in RA and OA patients.

Materials and methods

A systematic review with meta-analysis of randomized clinical trials(RCTs), published in English, between 1957–2021, was conducted using MEDLINE(PubMed), Embase and Cochrane Library. The methodological quality was assessed using Physiotherapy Evidence Database scale. The risk of bias was assessed using RoB2.0. Mean difference(MD) or standardized mean difference(SMD) and 95% confidence intervals(CI) were pooled using a random-effects model. A P<0.05 was considered statistically significant.

Results

Five RCTs were included. We found no significant differences in the effects between LIRTBFR, MIRT and HIRT on muscle strength, which was assessed by tests of quadriceps strength(SMD = -0.01[-0.57, 0.54], P = 0.96; I² = 58%) and functionality measured by tests with patterns similar to walking(SMD = -0.04[-0.39, 0.31], P = 0.82; I² = 0%). Compared to HIRT, muscle mass gain after LIRTBFR was reported to be similar. When comparing LIRTBFR with low intensity resistance training without blood flow restriction(LIRT), the effect LIRTBFR was reported to be higher on muscle strength, which was evaluated by the knee extension test.

Conclusion

LIRTBFR appears to be a promising strategy for gains in muscle strength, muscle mass and functionality in a predominant sample of RA and OA women.

Sarcopenic Obesity in Rheumatoid Arthritis: Prevalence and Impact on Physical Functioning

OBJECTIVE

We determined the prevalence of sarcopenic obesity in patients with rheumatoid arthritis (RA) using multiple methods and assessed associations with physical functioning.

METHODS

This study evaluated data from three RA cohorts. Whole-body dual-energy absorptiometry (DXA) measures of appendicular lean mass index (ALMI, kg/m2) and fat mass index (FMI) were converted to age, sex, and race-specific Z-Scores and categorized using a recently validated method and compared it to a widely-used existing method. The prevalence of body composition abnormalities in RA was compared with two reference populations. In the RA cohorts, associations between body composition and change in the Health Assessment Questionnaire (HAQ) and the Short Physical Performance Battery (SPPB) in follow-up were assessed using linear and logistic regression, adjusting for age, sex, race, and study.

RESULTS

The prevalence of low lean mass and sarcopenic obesity were higher in patients with RA (14.2; 12.6%, respectively) compared with the reference population cohorts (7-10%; 4-4.5%, respectively, all p< 0.05). There was only moderate agreement among methods of sarcopenic obesity categorization (Kappa 0.45). The recently validated method categorized fewer subjects as obese, and many of these were categorized as low lean mass only. Low lean mass, obesity, and sarcopenic obesity were each associated with higher HAQ and lower SPPB at baseline and numerically greater worsening.

CONCLUSION

RA patients had higher rates of low lean mass and sarcopenic obesity than the general population. The recently validated methods characterized body composition changes differently from traditional methods and were more strongly associated with physical function.

Changes in Body Composition, Muscle Strength, and Fat Distribution Following Kidney Transplantation

RATIONALE AND OBJECTIVE

Low muscle mass relative to fat mass (relative sarcopenia) has been associated with mortality and disability but has not been examined following transplantation. We studied how measures of body composition change after receipt of a kidney allograft.

STUDY DESIGN

Prospective longitudinal cohort study.

SETTING AND PARTICIPANTS

60 kidney transplant recipients (ages 20-60 years) at the University of Pennsylvania.

EXPOSURE

Kidney transplantation.

OUTCOMES

DXA measures of fat mass index (FMI) and appendicular lean mass index (ALMI; representing muscle mass), CT measures of muscle density (low density represents increased intramuscular adipose tissue), dynamometer measures of leg muscle strength, and physical activity. ALMI relative to FMI (ALM_FMI) is an established index of relative sarcopenia.

ANALYTICAL APPROACH

Measures expressed as age, sex, and race-specific Z-scores for transplant recipients were compared to 327 healthy controls. Regression models were used to identify correlates of change in outcome Z-scores and compare transplant recipients to controls.

RESULTS

At transplantation, ALMI, ALMI_FMI, muscle strength and muscle density Z-scores were lower vs. controls (all p≤0.001). Transplant recipients received glucocorticoids throughout. The prevalence of obesity increased from 18 to 45%. Although ALMI increased following transplantation (p<0.001) and was comparable to controls from 6 months onward, gains were outpaced by increases in FMI, resulting in persistent ALMI_FMI deficits (mean Z-score -0.31 at 24 months, p=0.02 vs controls). Muscle density improved following transplantation despite gains in FMI (p = 0.02). Muscle strength relative to ALMI also improved (p = 0.04) but remained low compared with controls (p=0.01). Exercise increased in the early months following transplantation (p<0.05) but remained lower than controls (p=0.02).

LIMITATIONS

Lack of muscle biopsies precluded assessment of muscle histology and metabolism.

CONCLUSIONS

The two-year interval following kidney transplantation was characterized by gains in muscle mass and strength that were outpaced by gains in fat mass resulting in persistent relative sarcopenia.

Association of Low Muscle Density With Deteriorations in Muscle Strength and Physical Functioning in Rheumatoid Arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is associated with low muscle density due to the accumulation of intramuscular fat. The present study was undertaken to identify predictors of changes in muscle density and to determine whether low muscle density predicted changes in strength and physical function.

METHODS

Patients with RA, ages 18-70 years, completed whole-body dual-energy x-ray absorptiometry and peripheral quantitative computed tomography to quantify lean and fat mass indices and muscle density. Dynamometry was used to measure strength at the hand, knee, and lower leg. Disability and physical function were measured with the Health Assessment Questionnaire (HAQ) and the Short Physical Performance Battery (SPPB). Assessments were performed at baseline and at follow-up. Regression analyses assessed associations between patient characteristics, muscle density, and deteriorations in strength and function.

RESULTS

Muscle density was assessed at baseline in 107 patients with RA. Seventy-nine of these patients (74%) returned for a follow-up assessment at a median follow-up time of 2.71 years (interquartile range 2.35-3.57). Factors associated with declines in muscle density included female sex, higher disease activity, smoking, and lower insulin-like growth factor 1 (IGF-1) levels. Greater muscle density Z score at baseline (per 1 SD) was associated with less worsening per year according to HAQ, SPPB, and 4-meter walk time scores and a lower risk of a clinically important worsening in HAQ score (odds ratio [OR] 1.90 [95% confidence interval (95% CI) 1.06, 3.42]; P = 0.03) and walking speed (OR 2.87 [95% CI 1.05, 7.89]; P = 0.04).

CONCLUSION

Worsening of skeletal muscle density occurred in patients with higher disease activity, in smokers, and in those with lower IGF-1. Low muscle density was associated with worsening of physical function. Interventions addressing reductions in muscle quality might prevent functional decline.

Assessment of muscle and fat mass in type 2 diabetes patients by dual-energy X-ray absorptiometry

OBJECTIVES

The aim of this study was to assess the quantitative composition of muscle and adipose tissue in type 2 diabetes mellitus (T2DM) patients on the basis of dual-energy X-ray absorptiometry for the diagnosis of obesity and sarcopenia.

METHODS

Dual-energy X-ray absorptiometry was administered to 50 patients with T2DM. Evaluation of the composition of muscle and adipose tissue was performed.

RESULTS

The median of Appendicular Lean Mass Index (ALMI) in the general group was 8.04 [7.32; 8.97]. In general, there was a decrease in the appendicular muscle mass with increasing age. According to the results of T-score ALMI and Z-score ALMI, we did not identify patients with sarcopenia. However, the calculation of the T- and Z-criteria, adjusted for fat mass, led to a significant decrease of these parameters and in 98.0% it was possible to identify patients who meet the criteria of sarcopenia.

CONCLUSION

We did not detect patients with sarcopenia on the basis of ALMI, T-ALMI. After revision of these criteria for fat mass, almost all patients started to meet the criteria of sarcopenia (98.0%).

Sarcopenic Obesity in Chronic Kidney Disease: Challenges in Diagnosis Using Different Diagnostic Criteria

OBJECTIVES

Obesity, muscle impairment (low muscle mass or strength), and sarcopenic obesity are present in chronic kidney disease (CKD) and are associated with worse clinical prognosis. However, the various existing definitions for these conditions make the diagnosis variable. The aim of the present study was to evaluate the agreement between diagnostic criteria for sarcopenic obesity and its components in CKD.

SUBJECT AND METHODS

267 patients with CKD were included in the study. We assessed body composition by dual-energy X-ray absorptiometry and muscle function by handgrip strength (HGS) and adiposity by body mass index (BMI), waist circumference (WC), fat mass index (FMI), and percentage of FM. Diagnosis of muscle impairment was made by HGS, appendicular lean mass (ALM), and ALM index; obesity by BMI, WC, FMI, and %FM, and sarcopenic obesity was diagnosed by concomitant presence of muscle impairment and obesity.

RESULTS

Prevalence of muscle impairment varied from 11 to 50%, higher when low muscle mass criteria were used. Prevalence of obesity varied from 26 to 62%, higher when WC and %FM criteria were used. Prevalence of sarcopenic obesity varied from 2 to 23%. Women were more affected by sarcopenic obesity. Muscle impairment and sarcopenic obesity were more prevalent among patients on hemodialysis and obesity among nondialysis-dependent and kidney transplant patients. The agreement was poor between muscle mass and strength criteria; substantial between FMI, BMI, and %FM and fair between WC and the other measures; for sarcopenic obesity, it varied from poor to almost perfect.

CONCLUSION

Significant differences were found among the various diagnostic criteria that are used in the diagnosis of sarcopenic obesity. Our results highlight the need for standardization in the diagnosis of sarcopenic obesity.

Changes in body composition and lipid profile in prostate cancer patients without bone metastases given Degarelix treatment: the BLADE prospective cohort study

BACKGROUND

Luteinizing hormone-releasing hormone (LHRH)-agonists in prostate cancer (PCa) patients induce sarcopenic obesity. The effect of LHRH-antagonist on body composition has never been explored. We evaluated changes in fat (FBM) and lean body mass (LBM) in PCa patients undergoing Degarelix.

METHODS

This is a single-center prospective study, enrolling 29 non-metastatic PCa patients eligible to LHRH-antagonist from 2017 to 2019. All patients received monthly subcutaneous injection of Degarelix for 12 months. Changes in FBM and LBM between baseline and 12-month Degarelix, as measured by dual-energy x-ray absorptiometry, were the co-primary endpoints. Secondary endpoints were changes in serum lipids, glucose profile and follicle-stimulating hormone (FSH). Appendicular lean mass index (ALMI) and ALMI/FBM ratio were assessed as post-hoc analyses. Linear mixed models with random intercept tested for estimated least squared means differences (EMD).

RESULTS

FBM significantly increased after 12 months (EMD +2920.7, +13.8%, p < 0.001), whereas LBM remained stable (EMD -187.1, -0.3%, p = 0.8). No differences occurred in lipid profile. Glycated hemoglobin significantly increased and serum FSH significantly decreased. A significant inverse relationship was found between serum FSH and ALMI/FBM ratio after 12 month (r = -0.44, p = 0.02).

CONCLUSIONS

The BLADE study prospectively evaluated changes in body composition after LHRH-antagonist. LHRH-antagonist therapy is associated to an increased risk of obesity and diabetes, but lean body mass and serum lipids are not affected. This may represent an additional evidence supporting the reduced cardiovascular risk associated with LHRH-antagonist. The role of FSH in influencing sarcopenic obesity in PCa after androgen deprivation deserves to be further explored.

Validation of a description of sarcopenic obesity defined as excess adiposity and low lean mass relative to adiposity

BACKGROUND

This study aims to assess the construct validity of a body composition-defined definition of sarcopenic obesity based on low appendicular lean mass relative to fat mass (ALMIFMI ) and high fat mass index (FMI) and to compare with an alternative definition using appendicular lean mass index (ALMI) and percent body fat (%BF).

METHODS

This is a secondary analysis of two cohort studies: the National Health and Examination Survey (NHANES) and the Health, Aging, and Body Composition study (Health ABC). Sarcopenic obesity was defined as low ALMIFMI combined with high FMI and was compared with a widely used definition based on ALMI and %BF cut-points. Body composition Z-scores, self-reported disability, physical functioning, and incident disability were compared across body composition categories using linear and logistic regression and Cox proportional hazards models.

RESULTS

Among 14, 850 participants from NHANES, patients with sarcopenic obesity defined by low ALMIFMI and high FMI (ALMIFMI -FMI) had above-average FMI Z-scores [mean (standard deviation): 1.00 (0.72)]. In contrast, those with sarcopenic obesity based on low ALMI and high %BF (ALMI-%BF) had below-average FMI Z-scores. A similar pattern was observed for 2846 participants from Health ABC. Participants with sarcopenic obesity based on ALMIFMI -FMI had a greater number of disabilities, worse physical function, and a greater risk of incident disability compared with those defined based on ALMI-%BF.

CONCLUSIONS

Body composition-defined measures of sarcopenic obesity defined as excess adiposity and lower-than-expected ALMI relative to FMI are associated with functional deficits and incident disability and overcome the limitations of using %BF in estimating obesity in this context.

Circulating Fibroblast Growth Factor-21 Levels in Rheumatoid Arthritis: Associations With Disease Characteristics, Body Composition, and Physical Functioning

OBJECTIVE

This study evaluated associations between fibroblast growth factor (FGF)-21, an adipokine associated with metabolic stress, and adverse longitudinal changes in body composition and physical functioning in patients with rheumatoid arthritis (RA).

METHODS

At baseline and follow-up, patients with RA aged 18-70 years completed whole-body dual-energy X-ray absorptiometry and peripheral quantitative computed tomography to quantify lean mass, fat mass, and muscle density. Dynamometry assessed muscle strength at the hand and knee, and physical functioning was measured with the Health Assessment Questionnaire (HAQ) and the Short Physical Performance Battery (SPPB). FGF-21 and inflammatory cytokines were measured at baseline. Linear and logistic regression analyses assessed associations between FGF-21 levels and both body composition and physical functioning over time.

RESULTS

There were 113 patients with RA enrolled, and 84 (74%) returned for follow-up at a median of 2.68 years. At baseline, FGF-21 was associated with age, smoking, methotrexate use, adiposity, and inflammatory cytokines: tumor necrosis factor receptor type I, YKL-40, vascular endothelial growth factor (VEGF), and resistin. The highest FGF-21 quartile was associated with worse SPPB and HAQ. Higher baseline FGF-21 levels (per 1 SD) were associated with worsening in muscle density and area Z-scores (β -0.06, 95% CI -0.12 to 0.008, P = 0.08; and β -0.05, 95% CI -0.10 to 0.006, P = 0.08, respectively) and a greater probability of a clinically meaningful worsening of HAQ (OR 2.37, 95% CI 1.21-4.64, P = 0.01). The fourth FGF-21 quartile was associated with worsening of SPPB (β -0.57, 95% CI -1.04 to -0.09, P = 0.02).

CONCLUSION

FGF-21 levels are associated with obesity and inflammatory cytokines, and with worsening in physical functioning in RA. These data support the hypothesis that FGF-21 can identify patients at risk of functional decline.

Body Composition in Young Adults Living With a Fontan Circulation: The Myopenic Profile

Background

We sought to characterize body composition abnormalities in young patients living with a Fontan circulation and explore potential pathophysiologic associations.

Methods and Results

Twenty‐eight patients with a Fontan circulation were prospectively recruited in this cross‐sectional study. Participants underwent cardiopulmonary exercise testing, dual‐energy X‐ray absorptiometry, echocardiography, and biochemical assessment. Mean age was 26±7 years. Skeletal muscle mass, estimated by appendicular lean mass index Z score, was reduced compared with reference data (−1.49±1.10, P<0.001). Percentage body fat Z score overall was within normal range (0.23±1.26, P=0.35), although 46% had elevated adiposity. Those with reduced skeletal muscle mass (appendicular lean mass index Z score of −1 or lower) had lower percent predicted oxygen pulse (55±15 versus 76±16%, P=0.002). Overall agreement between body mass index and dual‐energy X‐ray absorptiometry to assess adiposity was fair only (weighted [linear] κ coefficient: 0.53; 95% CI, 0.34–0.73) and slight in the setting of muscle mass deficiency (weighted κ coefficient: 0.32; 95% CI, 0.13–0.50). Appendicular lean mass was independently associated with absolute peak VO₂ (β=70.6 mL/min, P=0.001). Appendicular lean mass index Z score was inversely associated with hemoglobin (r=−0.4, P=0.04), and the degree of muscle deficit was associated with ventricular systolic impairment.

Conclusions

Young patients with a Fontan circulation have a body composition characterized by reduced skeletal muscle mass, which is associated with peak exercise capacity. Increased adiposity is common despite a normal body mass index. Low skeletal muscle mass is associated with systolic dysfunction and compensatory erythrocytosis.

Characteristics of Appendicular Tissue Components in Patients with Rheumatoid Arthritis

Background

The purpose of this study was to identify the characteristics of appendicular lean mass (ALM) associated with rheumatoid arthritis (RA) and to analyze appendicular tissue components in patients with RA.

Methods

We prospectively reviewed of patients with RA who underwent dual energy X-ray absorptiometry in a single center. From data of 28 patients, ALM was calculated. Regression analysis was used to investigate the association between ALM and RA. Using propensity score matching, patients with RA were compared to the control group from 18,698 patients of Korea National Health and Nutrition Examination Surveys data. RA and control group were matched in a 1: 5, respectively.

Results

In regression model, there was significantly negative association between disease activity score and ALM index in patients with RA in unadjusted (β=−0.387, 95% confidence interval [CI], −0.729 to −0.045) and model adjusted for age, sex, and body mass index (β=−0.227, 95% CI, −0.451 to −0.003). In matching with age and sex, the arms fat mass and fat fraction of RA group were significantly lower than that of control group. In matching with age, sex, and body mass index, the ALM index and legs lean mass of RA group were significantly higher than control group.

Conclusions

Patients with RA have a lower ALM with higher disease activity. In addition, we found that patients with RA had different tissue component in arms and legs compared to general population.

Estimation of Skeletal Muscle Mass Relative to Adiposity Improves Prediction of Physical Performance and Incident Disability

Purpose

We assessed the discrimination of lean mass estimates that have been adjusted for adiposity for physical functioning deficits and prediction of incident disability.

Methods

Included were 2,846 participants from the Health, Aging and Body Composition Study with available whole-body dual energy absorptiometry measures of appendicular lean mass index (ALMI, kg/m2) and fat mass index (FMI, kg/m2). Age-, sex-, and race-specific Z-Scores and T-Scores were determined by comparison to published reference ranges. ALMI values were adjusted for FMI (ALMIFMI) using a novel published method. Sex-stratified analyses assessed associations between lean mass estimates and the physical performance score, ability to complete a 400-meter walk, grip strength, and incident disability. Dichotomized definitions of low lean for age and sarcopenia were examined and their performance compared to the ALM-to-BMI ratio.

Results

Compared to ALMI T-Scores and Z-Scores, the ALMIFMI scores demonstrated stronger associations with physical functioning, and were similarly associated with grip strength. Greater FMI Z-Scores and T-Scores were associated with poor physical functioning and incident disability. Definitions of low lean for age and sarcopenia using ALMIFMI (compared to ALMI) better discriminated those with poor physical functioning and a greater risk of incident disability. The ALM-to-BMI ratio was modestly associated with grip strength and physical performance, but was not associated with completion of the 400-meter walk or incident disability, independent of adiposity and height.

Conclusion

Estimation of skeletal muscle mass relative to adiposity improves correlations with physical performance and prediction of incident disability suggesting it is an informative outcome for clinical studies.

Obesity, Weight Loss, and Progression of Disability in Rheumatoid Arthritis

OBJECTIVE

Cross-sectional studies have demonstrated that obese patients with rheumatoid arthritis (RA) often report greater disability. The longitudinal effects of obesity, however, are not well-characterized. We evaluated associations between obesity, weight loss, and worsening of disability in patients of 2 large registry studies, which included patients who were followed for longer periods of time.

METHODS

This study included patients with RA from the National Data Bank for Rheumatic Diseases (FORWARD) (n = 23,323) and the Veterans Affairs RA (VARA) registry study (n = 1,697). Results of the Health Assessment Questionnaire (HAQ) or Multidimensional HAQ (MD-HAQ) were recorded through follow-up. Significant worsening of disability was defined as an increase of >0.2 in HAQ or MD-HAQ scores. The Cox proportional hazards model was used to evaluate the risk of worsening of disability from baseline and to adjust for demographics, baseline disability, comorbidity, disease duration, and other disease features.

RESULTS

At enrollment, disability scores were higher among severely obese patients compared to those who were overweight both in FORWARD (β = 0.17 [95% confidence interval (95% CI) 0.14, 0.20]; P < 0.001) and in the VARA registry (β = 0.17 [95% CI 0.074, 0.27]; P = 0.001). In multivariable models, patients who were severely obese at enrollment had a greater risk of progressive disability compared to overweight patients in FORWARD (HR 1.25 [95% CI 1.18, 1.33] P < 0.001) and in the VARA registry (HR 1.33 [95% CI 1.07, 1.66]; P = 0.01). Weight loss following enrollment was also associated with a greater risk in both cohorts. In the VARA registry, associations were independent of other clinical factors, including time-varying C-reactive protein and swollen joint count.

CONCLUSION

Severe obesity is associated with a more rapid progression of disability in RA. Weight loss is also associated with worsening disability, possibly due to it being an indication of chronic illness and the development of age-related or disease-related frailty.

Relative sarcopenia and mortality and the modifying effects of chronic kidney disease and adiposity

BACKGROUND

Conventional definitions of sarcopenia based on lean mass may fail to capture low lean mass relative to higher fat mass, that is, relative sarcopenia. The objective of this study is to determine the associations of sarcopenia and relative sarcopenia with mortality independent of co-morbidities, and whether chronic kidney disease (CKD) and adiposity alter these associations.

METHODS

Dual energy X-ray absorptiometry-derived appendicular lean mass index (ALMI, kg/m2 ) and fat mass index (FMI, kg/m2 ) were assessed in 14 850 National Health and Nutrition Examination Survey participants from 1999 to 2006 and were linked to death certificate data in the National Death Index with follow-up through 2011. Sarcopenia was defined using sex-specific and race/ethnicity-specific standard deviation scores compared with young adults (T-scores) as an ALMI T-score < -2 and relative sarcopenia as fat-adjusted ALMI (ALMIFMI ) T-score < -2. Glomerular filtration rate (GFR) was estimated using creatinine-based (eGFRCr ) and cystatin C-based (eGFRCys ) regression equations.

RESULTS

Three (3.0) per cent of National Health and Nutrition Examination Survey participants met criteria for sarcopenia and 8.7% met criteria for relative sarcopenia. Sarcopenia and relative sarcopenia were independently associated with mortality (HR sarcopenia 2.20, 95% CI 1.69 to 2.86; HR relative sarcopenia 1.60, 95% CI 1.31 to 1.96). The corresponding population attributable risks were 5.2% (95% CI 3.4% to 6.4%) and 8.4% (95% CI 4.8% to 11.2%), respectively. Relative sarcopenia remained significantly associated with mortality (HR 1.32, 95% CI 1.08 to 1.61) when limited to the subset who did not meet the criteria for sarcopenia. The risk of mortality associated with relative sarcopenia was attenuated among persons with higher FMI (P for interaction <0.01) and was not affected by CKD status for either sarcopenia or relative sarcopenia.

CONCLUSIONS

Sarcopenia and relative sarcopenia are significantly associated with mortality regardless of CKD status. Relative sarcopenia is nearly three-fold more prevalent amplifying its associated mortality risk at the population level. The association between relative sarcopenia and mortality is attenuated in persons with higher FMI.

Comparisons of different indices of low muscle mass in relationship with cardiometabolic disorder

This study aimed to evaluate the most valid index among various indices of low muscle mass in assessing cardiometabolic risks in a Korean population. Appendicular lean mass index (ALMI, kg/m2), fat mass index (FMI, kg/m2), FMI-adjusted ALMI (ALMfmi), ratio of ALM to weight index (ALMwt), ratio of ALM to body mass index (ALMbmi) and ratio of ALM to truncal fat index (ALMtrunkfat) were measured by dual energy X-ray absorptiometry in 17,870 participants from 2008 to 2011. We adopted all the aforementioned indices of low muscle mass expressed as sex- and age-specific standard deviation scores (Z-scores). Low muscle mass for age was defined as Z-score <-1. The prevalence of low muscle mass was approximately 16% across all indices. Low muscle mass defined by ALMI had low muscle mass and low fat mass, and ALMfmi had low muscle mass at the same FMI. However, low muscle mass defined by ALMwt, ALMbmi and ALMtrunkfat had similar muscle mass with high FMI. The receiver operating characteristic curve in metabolic syndrome showed that the ALMtrunkfat was 0.74 in male and 0.69 in female, indicating that ALMtrunkfat was the best discrimination index for metabolic syndrome. This study showed that ALMtrunkfat could be a useful indicator for screening cardiometabolic risk factors, particularly in normal or overweight Asian population.

Intramuscular Fat Accumulation and Associations With Body Composition, Strength, and Physical Functioning in Patients With Rheumatoid Arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is associated with adverse body composition profiles and low muscle density due to the accumulation of intramuscular fat. Linear regression was used to assess differences between RA patients and controls and to determine associations between muscle density, strength, and physical functioning.

METHODS

Patients with RA, ages 18-70 years, and healthy control subjects underwent whole-body dual x-ray absorptiometry and peripheral quantitative computed tomography, in order to quantify the appendicular lean mass index (ALMI) and the fat mass index (FMI), visceral fat area, and muscle density. Dynamometry was used to measure hand grip strength and muscle strength at the knee and lower leg. Disability and physical functioning were measured using the Health Assessment Questionnaire (HAQ) and the Short Physical Performance Battery (SPPB). Linear regression analyses were performed to assess differences related to RA and associations between muscle density, strength, and function.

RESULTS

The study group included 103 patients with RA (51 men) and 428 healthy control subjects. Among patients with RA, low muscle density was associated with higher disease activity, C-reactive protein and interleukin-6 levels, greater total and visceral fat area, lower ALMI Z scores, physical inactivity, and long-term use of glucocorticoids (>1 year). Patients with low ALMI Z scores had lower muscle density Z scores compared with reference participants with similarly low ALMI scores. Low muscle density was independently associated with lower muscle strength, higher HAQ scores, and lower SPPB scores, after adjustment for ALMI and FMI Z scores.

CONCLUSION

The low muscle density observed in patients with RA was associated with low muscle mass, excess adiposity, poor strength, and greater disability. Interventions to address poor muscle quality could potentially affect important functional outcomes.

Prevalence of rheumatoid cachexia in rheumatoid arthritis: a systematic review and meta-analysis

BACKGROUND

Low muscle mass occurs in patients with rheumatoid arthritis without weight loss; this condition is referred as rheumatoid cachexia. The aim of the current study was to perform a systematic review with meta-analysis to determine the rheumatoid cachexia prevalence.

METHODS

A systematic review with meta-analysis of observational studies published in English, between 1994 and 2016, was conducted using MEDLINE (via PubMed) and other relevant sources. Search strategies were based on pre-defined keywords and medical subject headings. The methodological quality of included studies was assessed using the Newcastle-Ottawa Scale. Meta-analysis was used to estimate the prevalence, and because studies reported different methods and criteria to estimate body composition and prevalence of rheumatoid cachexia, subgroup analyses were performed. Meta-regression adjusted for the 28-joint disease activity score and disease duration (years) was performed (significance level at P ≤ 0.05).

RESULTS

Of 136 full articles (one duplicate publication) screened for inclusion in the study, eight were included. The estimated overall prevalence of rheumatoid cachexia was 19% [95% confidence interval (CI) 07-33%]. This prevalence was 29% (95% CI 15-46%) when body composition was measured by dual-energy X-ray absorptiometry. When the diagnostic criteria were fat-free mass index below the 10th percentile and fat mass index above the 25th percentile, rheumatoid cachexia prevalence was 32% (95% CI 14-52%). The 28-joint disease activity score and disease duration had no influence on the estimated prevalence of rheumatoid cachexia (P > 0.05). Most studies were rated as having moderate methodological quality.

CONCLUSIONS

Meta-analysis showed a prevalence of rheumatoid cachexia of 15-32%, according to different criteria, demonstrating that this condition is a frequent comorbidity of rheumatoid arthritis. To better understand its clinical impact, more studies using standardized definitions and prospective evaluations are urgently needed.

Body composition by DXA

Body composition measurements from DXA have been available since DXA technology was developed 30years ago, but are historically underutilized. Recently, there have been rapid developments in body composition assessment including the analysis and publication of representative data for the US, official usage guidance from the International Society for Clinical Densitometry, and development of regional body composition measures with clinical utility. DXA body composition is much more than whole body percent fat. In this paper celebrating 30years of DXA for body composition, we will review the principles of DXA soft tissue analysis, practical clinical and research applications, and what to look for in the future.

Muscle Deficits in Rheumatoid Arthritis Contribute to Inferior Cortical Bone Structure and Trabecular Bone Mineral Density

OBJECTIVE

Rheumatoid arthritis (RA) is associated with muscle loss, osteoporosis, and fracture. We examined associations between skeletal muscle mass, strength, and quality and trabecular and cortical bone deficits in patients with RA and healthy controls.

METHODS

Participants, ages 18-75 years, completed whole-body dual-energy x-ray absorptiometry and peripheral quantitative computed tomography (pQCT) of the tibia to quantify appendicular lean mass and fat mass indices (ALMI, FMI), muscle density at the lower leg, trabecular bone density, and cortical bone thickness. Age-, sex-, and race-specific Z scores were calculated based on distributions in controls. Associations between body composition and pQCT bone outcomes were assessed in patients with RA and controls. Linear regression analyses assessed differences in bone outcomes after considering differences in body mass index (BMI) and body composition.

RESULTS

The sample consisted of 112 patients with RA (55 men) and 412 controls (194 men). Compared to controls, patients with RA had greater BMI Z score (p < 0.001), lower ALMI Z score after adjustment for FMI (p = 0.02), lower muscle strength Z score (p = 0.01), and lower muscle density Z score (p < 0.001). Among RA, ALMI Z scores were positively associated with trabecular density [β: 0.29 (0.062-0.52); p = 0.01] and cortical thickness [β: 0.33 (0.13-0.53; p = 0.002]. Associations were similar in controls. Bone outcomes were inferior in patients with RA after adjusting for BMI, but similar to controls when adjusting for body composition. Radiographic damage and higher adiponectin levels were independently associated with inferior bone outcomes.

CONCLUSION

Patients with RA exhibit deficits in cortical bone structure and trabecular density at the tibia and a preserved functional muscle-bone unit. A loss of mechanical loading may contribute to bone deficits.

Assessment of muscle mass relative to fat mass and associations with physical functioning in rheumatoid arthritis

Objectives

To determine whether a novel measure of appendicular lean mass relative to fat mass is associated with physical functioning in RA.

Methods

In a cross-sectional design, three independent RA cohorts were retrospectively analysed. Whole-body DXA measures of appendicular lean mass index (ALMI, kg/m 2 ) and fat mass index (FMI, kg/m 2 ) were converted to age, sex and race-specific Z-scores using published National Health and Nutrition Examination Survey reference ranges. Adiposity-adjusted ALMI Z-scores (ALMI FMI ) were determined using a published method to adjust for normal associations between ALMI and FMI Z-scores. Associations between ALMI Z-scores, ALMI FMI Z-scores and physical functioning were assessed after adjusting for age, sex and study. Functional outcomes assessed included the HAQ, Valued Life Activities assessment and Short Physical Performance Battery. Low lean for age was defined as a Z-score of -1 or less.

Results

Our sample consisted of 442 patients with RA. The combined cohort had a mean ALMI Z-score of - 0.51 (1.08) and a mean ALMI FMI Z-score of - 0.58 (1.53), suggesting muscle mass deficits compared with a nationally representative sample. Greater ALMI FMI Z-scores demonstrated stronger associations with better functional outcomes compared with ALMI Z-scores. Associations were not attenuated with adjustment for systemic inflammation or pain. The FMI Z-score was independently associated with physical functioning, with a stronger association seen among patients with greater FMI Z-score. Adiposity-adjusted definitions of low lean mass more clearly identified those with functional impairment.

Conclusion

Estimates of appendicular lean mass that are adjusted for adiposity demonstrate stronger positive associations with functional outcomes compared with unadjusted estimates.

Frailty and reduced physical function go hand in hand in adults with rheumatoid arthritis: a US observational cohort study

Reduced physical function and health-related quality of life are common in rheumatoid arthritis (RA), and further studies are needed that examine novel determinates of reduced physical function in RA. This study examines whether frailty, a state of increased vulnerability to stressors, is associated with differences in self-reported physical function among adults with RA. Adults from a longitudinal RA cohort (n = 124) participated in the study. Using an established definition of frailty, individuals with three or more of the following physical deficits were classified as frail: (1) body mass index ≤18.5, (2) low grip strength (adjusted for sex and body mass index (BMI), measured by handheld dynamometer), (3) severe fatigue (measured by the Multidimensional Assessment of Fatigue), (4) slow 4-m walking speed (adjusted for sex and height), and (5) low physical activity (measured by the International Physical Activity Questionnaire). Individuals with one or two deficits were classified as "pre-frail" and those with no deficits as "robust." Self-reported physical function was assessed by the Health Assessment Questionnaire (HAQ) and the Valued Life Activities Difficulty scale. Regression analyses modeled associations of frailty category with HAQ and Valued Life Activities (VLA) Difficulty scores with and without controlling for age, sex, disease duration, C-reactive protein, use of oral steroids, and pain. Among adults with RA, being frail compared to being robust was associated with a 0.44 worse VLA score (p < 0.01) when the effects of covariates are held constant. Being frail, compared to being robust, is associated with clinically meaningful differences in self-reported physical function among adults with RA.