Impact of Rheumatoid Arthritis on Body Composition, Bone Marrow Adiposity and Bone Mineral Density: a Case-control Study

Inclusion Criteria: Subjects: Males and females of age (age ≥ 18 years). Patients with RA according to American College of Rheumatology/EULAR 2010 criteria, Patients who have signed the informed consent Controls: Males and females of age (age ≥ 18 years). subjects who have signed the informed consent Exclusion Criteria: * Patients who have received more than three anti-TNFinhibitors * Patients who have previously received a Janus kinase (JAK) inhibitor * Patients with concomitant therapies as described below : A combination with methotrexate is allowed if methotrexate is started ≥3 months before the start of the study and at a stable dosage (≤25 mg/week) for ≥4 weeks. A combination to conventional synthetic DMARDs (csDMARDs) other than methotrexate is not allowed within 4 weeks before and/or during the clinical trial * Corticosteroid therapy \>10mg/d prednisolone equivalent is not allowed * Intra-articular injections of corticosteroids are allowed if their number is less than or equal to 4 * Intravenous corticosteroid infusions are not allowed * Immunosuppressants other than methotrexate are not allowed * History or discovery of an osteoporotic fracture AND/OR T-score ≤-3 if ≥50 years old AND/OR Z-score ≤-3 if \<50 years old during the screening phase, * Corticosteroid therapy ≥ 10mg/d prednisolone equivalent, * Pathologies or treatments affecting bone metabolism (breast cancer with antiaromatase, digestive malabsorption, stomach cancer, primary hyperparathyroidism, uncontrolled hyperthyroidism...), * History of radiotherapy on the lumbar spine or the hip studied, * Patients undergoing hormone replacement therapy (HRT) or patients already under anti-osteoporotic treatment (bisphosphonates, strontium ranelate, teriparatide or denosumab) apart from calcium and/or vitamin D supplementation, Chronic renal failure with creatinine clearance (CKD-EPI formula) ≤ 30 ml/min,