The relation between sarcopenia, associated factors, and disease activity in patients with rheumatoid arthritis

Aim The aim of this study was to detect the incidence of sarcopenia in patients with rheumatoid arthritis (RA) and study associated factors. Patients and methods Dual-energy X-ray absorptiometry was used to assess the body composition of 80 patients with RA and 80 healthy controls. Sarcopenia was defined as a relative skeletal muscle index of less than 5.5 kg/m2 in male and less than 7.26 kg/m2 in female patients. BMI, waist circumference, and disease activity score 28 erythrocyte sedimentation rate were used to assess disease activity. Functional disability was measured using Health Assessment Questionnaire, and 4-m gait speed test was used to determine patient's physical performance. Results The relative skeletal muscle index was significantly lower in the RA group (6.1 ± 1.2 vs. 7.2 ± 0.9 kg/m2, P < 0.0001). Thirty-one (38.8%) patients in the RA group had sarcopenia. Sarcopenia in RA group was not related to age, disease duration, steroid therapy, and disease activity assessed by disease activity score 28 erythrocyte sedimentation rate. Most of the patients with sarcopenia were preobese, and 67% had abnormal waist circumference (102.1 ± 14.9 vs. 98.9 ± 12.0 cm, P = 0.003). There was no significant relation between sarcopenia and the Health Assessment Questionnaire score (P = 0.057), and both subgroups were comparable regarding the extent of physical disability (P = 0.448) and performed similarly on the 4-m gait speed test (P = 0.800). The only independent predictor was male sex in our patients with RA. Conclusion Sarcopenia is a common finding in patients with RA but does not have an association with disease activity, functional disability, or physical performance. Future studies are required for better comprehension of sarcopenia to clear up its relationship with different comorbidities.