Rheumatoid cachexia: a complication of rheumatoid arthritis moves into the 21st century

Immunology R&D, Biogen Idec, Inc,, Cambridge, MA 02142, USA. .
Arthritis research & therapy (Impact Factor: 4.12). 04/2009; 11(2):108. DOI: 10.1186/ar2658
Source: PubMed

ABSTRACT Rheumatoid cachexia, loss of muscle mass and strength and concomitant increase in fat mass, is very common in patients with rheumatoid arthritis (RA). Despite great advances in the treatment of RA, it appears that rheumatoid cachexia persists even after joint inflammation improves. Rheumatoid cachexia may be an important risk factor for cardiovascular disease and excess mortality in RA. In this issue of Arthritis Research & Therapy, Elkan and colleagues demonstrate a link between rheumatoid cachexia and metabolic syndrome, further reinforcing the need for therapy directed beyond inflammation and at the metabolic consequences of RA.

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    ABSTRACT: PurposeTo quantify muscle outcomes, independent of fat mass, in rheumatoid arthritis (RA) compared to healthy controls.Methods Quantitative CT scans measured calf muscle and fat cross-sectional area and muscle density (an index of intramuscular adipose tissue), and isometric dynamometry was used to measure ankle muscle strength in 50 participants with RA, ages 18-70 years, and 500 healthy controls. Multivariable linear regression models assessed muscle deficits in RA after adjusting for group differences in adiposity and assessing for an altered muscle-fat association. Associations between RA disease characteristics and fat-adjusted muscle outcomes were also assessed.ResultsCompared to controls, RA subjects had significantly greater body mass index (BMI) and fat area, and lower muscle area, muscle density and muscle strength (all p<0.001). Strength deficits were eliminated with adjustment for the smaller muscle area. The magnitude of muscle deficits, relative to controls, was significantly greater (interaction p<0.03) in participants with lower fat area and BMI. Among those with in the lower tertiles of adiposity, RA subjects demonstrated more significant deficits compared to controls with similar adiposity. In contrast, among those in the highest tertile for adiposity, RA was not associated with muscle deficits. Among RA, greater vdHS scores were associated with lower muscle CSA and muscle density. Greater disease activity and disability were associated with low muscle density..Conclusions Deficits in muscle area and muscle density are present in RA compared to controls and are most pronounced in subjects with low fat mass. Greater joint destruction is associated with greater muscle deficits. © 2014 American College of Rheumatology.
    11/2014; 66(11). DOI:10.1002/acr.22328
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    ABSTRACT: Objective: Limited data exist describing relationships between muscle strength, muscle mass, and physical disability among individuals with systemic lupus erythematosus (SLE). The present study examines the relationship of muscle strength and muscle mass with physical disability among adult women with SLE.Methods: One hundred forty-six women from a longitudinal SLE cohort participated in the study. All measures were collected during an in-person research visit. Lower extremity muscle strength was assessed by peak knee torque of extension and flexion and by chair-stand time. Total lean body mass, appendicular lean mass, and fat mass (kg/m2) were measured by whole-body dual energy absorptiometry. Self-reported physical disability was assessed using the SF-36 Physical Functioning subscale and Valued Life Activities (VLA) Disability scale. Spearman's rank correlation coefficients tested the correlations between muscle strength, muscle mass, and disability scores. Regression analyses modeled the effect of lower extremity muscle strength and mass on SF-36 and VLA disability scores controlling for age, SLE duration, SLE disease activity measured with the Systemic Lupus Activity Questionnaire (SLAQ), physical activity level, prednisone use, body composition, and depression.Results: On all measures, reduced lower extremity muscle strength was associated with poorer SF-36 and VLA disability scores. Trends persisted after adjustment for covariates. Muscle mass was moderately correlated with muscle strength, but did not contribute significantly to adjusted regression models.Conclusions: Lower extremity muscle strength, but not muscle mass, was strongly associated with physical disability scores. While further studies are needed, these findings suggest that improving muscle strength may reduce physical disability among women with SLE. © 2014 American College of Rheumatology.
    01/2015; 67(1). DOI:10.1002/acr.22399
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    ABSTRACT: Purpose: We aimed to determine if there were gender differences in lean body mass (LBM) in patients with RA when compared with sex- and race- specific National Health and Nutrition Examination Survey (NHANES) reference data, and investigated the impact of sex differences in risk factors for LBM deficits.Methods: DXA measures of whole body LBM and appendicular LBM (arms and legs, ALM) were obtained on a total of 190 subjects from two independent cohorts (141 from San Francisco (SF), 49 from Philadelphia (PA)), expressed as indices adjusted for height (LBMI and ALMI, kg/m2), and converted to sex- and race- specific Z-scores relative to age based on NHANES data. Sarcopenia was defined using four different sex-specific definitions. Multivariable linear and logistic regression adjusted analyses for disease activity, disease duration, physical activity, CCP seropositivity, fat mass index, and glucocorticoid use.Results: While there were significant differences between the two cohorts, ALMI Z-scores were significantly lower in men compared to women in both (SF: -1.43 v. -0.43, p<0.0001; PA: -0.83 v. -0.06, p=0.03). Observed gender differences were significant after adjustment in multivariable analyses within both cohorts. Odds of sarcopenia were 3 to 8 times greater in men in the SF cohort. Men in the PA cohort also had a higher, but non-significant, risk of sarcopenia.Conclusion: RA is associated with significant LBM deficits, with greater deficits observed in men. Future study may help elucidate the mechanisms driving greater deficits among men. © 2014 American College of Rheumatology.
    01/2015; 67(1). DOI:10.1002/acr.22396

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