Comparison of methods for diagnosing sarcopenia in patients with rheumatoid arthritis

Abstract

Background. Sarcopenia in patients with rheumatoid arthritis (RA) occurs in connection with the chronic inflammatory process, hormonal therapy, and limitation of physical activity due to pain syndrome. For RA patients, it is important to preserve muscle mass and function to reduce the risk of disability and improve quality of life. The research purposed to assess muscle mass and function in RA patients with a comparison of me­thods for determining skeletal muscle mass recommended by ­EWCSOP2. ­Materials and methods. A total of 44 persons were exa­mined, 32 were patients with RA, and 12 ones were healthy persons (the control group). The following methods were used in the study: the SARC-F questionnaire, the determination of the appendicular mass of skeletal muscles using dual-photon X-ray absorptiometry (DXA), the percentage of muscle and fat tissue using bioimpe­dancemetry, the determination of the cross-sectional area of the lumbar muscle using computer tomography (CT), physical performance tests. Patients with RA were divided into 3 groups: group A (11 persons) — questionnaire (SARC-F), assessment of skeletal muscle strength and determination of muscle mass using DXA was performed; group B (11 patients) — questionnaire (SARC-F), assessment of skeletal muscle strength and determination of muscle mass using bioimpedancemetry; group C (10 persons) — questionnaire (SARC-F), assessment of skeletal muscle strength and determination of muscle mass using CT. Results. All indices of physical performance tests and instrumental methods of assessing muscle mass were significantly worse in patients with RA compared to the control group. Sarcopenia was diagnosed in 50 % of patients with RA, 6 cases in group A (the average value of appendicular lean mass was 15.7 kg in them, in the control group — 21 kg), 5 in group B (the average values of the proportion of muscle mass were 21.2 compared to 29.3 % in the control group) and 5 in group C (the average percentage of muscle mass was 49.46 %, in the control group 58.32 %). ­Conclusions. Each of the methods of assessing the mass of skeletal muscles has proven its ability in the diagnosis of sarcopenia. Improving the efficiency of diagnosing sarcopenia in patients with RA will improve the response to the treatment of the underlying disease and improve the quality of life of patients.