Background Sarcopenia refers to age-related loss of muscle mass and function. However, autoimmune sarcopenia refers to excessive weight loss usually with disproportionate muscle wasting due to cytokine excess. Previous studies have found a frequency of autoimmune sarcopenia of about 15 to 20%. The progressive loss of muscle mass lead to decrease in physical activity and a rise in cardiovascular and metabolic disorders. There is currently no widely accepted definition of sarcopenia in autoimmune diseases.
Objectives The purpose of this study was to determine the frequency of muscle wasting in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE).
Methods In a cross-sectional study, we screened the patients from outpatient clinic in the rheumatology service and were excluded patients with chronic disorders of heart, kidney and liver, also the patients that were on HMG-CoA reductase inhibitors treatment; we performed medical history and physical examination, specialist in clinical nutrition made the anthropometric measures, blood samples were taken for clinical laboratory analysis. Activity scales for each disease were made, DAS-28 in RA and MEX-SLEDAI in SLE patients. We determined the whole body lean mass using Dual-emission X-ray Absorptiometry (DEXA). Statistical analysis was performed using arithmetic mean, standard deviation, Student T test; chi-square and Fisher exact test when appropriate and Spearman rank correlation test all using SPSS program (v 12.0).
Results Forty-six patients with autoimmune disease (AID), twenty six patients with RA and 20 with SLE according to the 1987 ACR criteria and 25 healthy subjects were analyzed; mean age of AID was 40±13.4 vs. 39±18 years in control group. Ninety-four percent were women. 90% of the AID group was taking hydroxychloroquine and 80% was on mild doses of corticosteroids. The anthropometric measures revealed obesity in 28% of the patients vs 16% in control group. The frequency of sarcopenia in AID group was 26% (12 pts) vs 20% (5 pts) in control group, p=0.000; There was no difference in the cases of sarcopenic-obesity. The risk of sarcopenia in sedentary patients was OR 1.93 (IC 95% 0.385 to 9.7). There was no correlation between activity scales of AID and sarcopenia rho =0.121 for SLE and rho=0.170 in RA patients. The use of hydroxychloroquine is not protection for muscle wasting OR 1.4 (IC 95% 0.147 to 14.59). Finally the risk of sarcopenia in patients with AID was OR 1.4 (IC 95% 0.434 to 4.596).
Conclusions Our work demonstrated that patients with AID have a slightly risk of sarcopenia when are compared to control group. This finding may affect the quality of life and promote the increasing of morbidity in such patients.
Santos MJ, Vinagre F, Canas Da silva J, Gil V, Fonseca JE. Body composition phenotypes in systemic lupus erythematosus and rheumatoid arthritis: a comparative of caucasian female patients. Clin Exp Rheum; 2011 29: 470-476
Disclosure of Interest None Declared