JAKPOT (JAK Inhibitors and Predictors of Outcome in RheumaToid Arthritis)

Rheumatoid arthritis (RA) is a chronic, progressive autoimmune disease associated with inflammation and destruction of joints and systemic effects, which result in significant impact on patient's quality of life and function. Sustained remission or low disease activity is the target to achieve in RA management. Ultrasound (US) is an imaging technique potentially helpful at several steps of the disease. A semi-quantitative (0-3) score of synovitis combining B-mode and Power Doppler abnormalities has been developed (GLOESS), and its responsiveness has been demonstrated. Patients Reported Outcomes (PROs) are important parameters in patient perceived health and are increasingly used in clinical practice. Prediction of therapeutic response to biological and targeted synthetic DMARDs remains a challenge for clinician, due to the potential adverse events and the cost of these drugs. To date, only few clinical and biological tools usable in clinical practice have a prognostic value. US or PRO could have added value for this purpose. Objectives : * To determine the predictive added value of the variation of an US score to the variation of the DAS28-CRP (C-Reactive Protein) at 1 month on clinical outcome (low disease activity i.e. DAS28-CRP≤3.2) at 6 months, or on therapeutic response at 3 months (EULAR good or moderate response (DAS)), in RA patients starting a treatment with JAK (Janus Kinase) inhibitors (JAKi). * To determine the predictive added value of the variation several PROs to the variation of the DAS28-CRP at 1 month on clinical outcome (low disease activity i.e. DAS28-CRP≤3.2) at 6 months, or on therapeutic response at 3 months (EULAR good or moderate response (DAS)), in RA patients starting a treatment with JAKi.