Background:Inflammation, decreased physical activity, hormonal disorders, and the use of glucocorticoids lead to changes in the composition of the body in rheumatoid arthritis (RA). Various combinations of decreased muscle and bone mass and increased adipose tissue have led to the release of various pathological phenotypes of the composition of the body.Objectives:To determine the frequency of pathological phenotypes of body composition in patients with RA.Methods:The study included 79 women with RA, with a median age of 60 y.o. [55; 65]. 92% of the women were postmenopausal. The median duration of the disease was 9 years [3; 11]. Basic anti-inflammatory therapy was received by 81% of patients. Methotrexate was used most often as the basic therapy – in 52% of cases. 49% of patients were treated with glucocorticoid drugs. All patients underwent dual-energy X-ray absorptiometry. The mineral density of the tissues was determined in the standard measurement areas - the spine and the proximal thigh, and the content of muscle and adipose tissue was analyzed. We calculated appendicular muscle mass (AMM), which is the sum of upper and lower limb muscle mass and appendicular muscle index (AMI), the ratio of appendicular muscle mass to the square of height. AMM< 15 kg, AMI < 6 kg / m2 corresponds to sarcopenia.Results:The average AMM was 17.8±3.0 kg. 18% patients had AMM <15 kg / m2. The average AMI was 6.8±1.0 kg / m2. 25% patients had AMI < 6 kg/m2. The average body mass index (BMI) was 27.6±4.8 kg/m2. 37% patients were overweight (25≤ BMI <29.9 kg/m2), 28% of women had a BMI corresponding to obesity. The average fat content was 28.2 kg. 71% of women had an obesity, according to X-ray absorptiometry, which is 2.5 times higher than the number of cases of obesity detected by BMI. A decrease a bone mineral density (BMD) was found in 73% of women, including osteoporosis in 25%. The most frequent phenotype was osteopenic obesity (Table 1), which was detected in almost 40% of patients. Isolated osteoporosis (16.5%) and obesity (17.7%) and osteosarcopenic obesity (16.5%) were found with approximately the same frequency. Osteosarcopenia was found in 9% of patients. In 4%, no changes in the compositional composition of the human body were detected.Table 1.Pathological phenotypes of body compositionPathological phenotypes of body compositionn=79Osteoporosis, n (%)13 (16,5)Obesity, n (%)14 (17,7)Osteosarcopenia, n (%)7 (8,9)Osteopenic obesity, n (%)29 (36,7)Osteosarcopenic obesity, n (%)13 (16,5)Conclusion:The overall frequency of pathological phenotypes of body composition was high and amounted to 96.2% in women with RA. The most common pathological phenotype was an osteopenic obesity characterized by a decrease in BMD and an increase in fat mass.Disclosure of Interests:None declared