Appendicular lean mass in women with rheumatoid arthritis: Focus on immunological markers

Aim – to evaluate the association among appendicular lean mass and immunological markers of blood serum in women with rheumatoid arthritis (RA). Material and methods . 200 women with RA (median age – 60.0 [52.5; 65.5] years) were enrolled in the study. Using dual-energy X-ray absorptiometry appendicular lean mass (ALM) was measured to determine the sarcopenic phenotype of body composition. The assessment of C-reactive protein (CRP), rheumatoid factor, and antibodies to cyclic citrullinated peptide was also performed. The levels of serum myostatin, follistatin, interleukin 6 (IL-6), IL-6 receptors, insulin-like growth factor 1 (IGF-1), adiponectin, leptin, fibroblast growth factor 23 (FGF23), tumor necrosis factor SF12 (superfamily member 12) were studied in 87 patients. Results . According to the presence of the sarcopenic phenotype the patients differed in the levels of CRP (8.6 [1.3; 22.2] and 5.6 [1.2; 17.4] mg/l, respectively; p=0.041) and leptin (3.8 [2.4; 5.7] and 5.4 [3.8; 6.9] ng/ml, respectively; p=0.030). ALM correlated with the levels of CRP, follistatin and leptin. Linear multivariate regression analysis revealed the association between ALM index and follistatin (β=–0.35; p=0.007), IGF1 (β=–0.38; p=0.002), leptin (β=0.36; p=0.004) and FGF23 (β=0.33; p=0.008). Conclusion . The study showed that there is an association between the lean mass and the level of follistatin, IGF-1, leptin and FGF23 in patients with RA.