Ultrasound in Psoriatic Arthritis Treatment

BACKGROUND Psoriatic arthritis (PsA) is a systemic inflammatory disease with articular and extra-articular features. Establishing the prognosis of a patient with PsA is hence important to define the treatment strategy. Currently, observational and prospective cohort studies have identified prognostic factors correlating with the achievement of therapeutic response. Nevertheless, despite the importance of identifying prognostic factors in a disease with a functional disability comparable to rheumatoid arthritis, the studies are still limited. PRIMARY OBJECTIVE In PsA with clinically active joint disease starting a new course of therapy, to evaluate the additional value of UltraSound(US)-score over clinical examination in detecting patients achieving MDA at 6 months. STUDY DESIGN The study follows a multi-centre observational prospective cohort study design. PATIENTS AND METHODS INCLUSION CRITERIA * Adult \> 18 years of age with PsA (PsA according to the ClASsification criteria for Psoriatic Arthritis (CASPAR) - with joint involvement) * At least one joint clinically involved (both swelling and tenderness); * prescription of new course of d NSAIDs (monotherapy), steroid intra-articular injections (monotherapy), conventional Disease-Modifying AntiRheumatic Drugs (DMARDs), biologic DMARDs, including switches or dose augmentations indicated by the treating rheumatologist according to usual clinical practice before US acquisition; * Stable treatment before treatment modification (6 weeks); * Signed informed consent form. CLINICAL ASSESSMENT Patient's clinical assessment will be performed according to the core set of domains for PsA proposed by the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) and Outcome Measures in Rheumatology (OMERACT). ULTRASOUND ASSESSMENT Sonographic evaluations will be performed by expert ultrasonographers in 44 joints, 36 tendons, 12 entheses and 2 bursae according to the score developed for psoriatic arthri