A Multicentre Observational Psoriatic Arthritis Cohort Study Addressing Real-life Outcomes of a Treat to Target Approach in Routine Clinical Practice.

This study is observational. Patients will receive standard treatment as given in usual clinical practice with no intervention as part of the study. As per current clinical practice guidelines and UK reimbursement rules for biologics in PsA, patients will receive a pragmatic treat to target approach using step up standard therapies. Patients will usually receive methotrexate first line, initially 15mg ow increasing to 25mg ow as tolerated. In case of non-response, an additional DMARD will be used (sulfasalazine up to 3g daily or leflunomide 20mg od). If two DMARDs are failed and patients are eligible for biologic therapy under UK National Institute of Health and Clinical Excellence (NICE) guidance, then biologics will be used.

This study is observational and patients will receive treatment for their psoriatic arthritis as clinically indicated. As per standard practice in this observational cohort, patients are most likely to be treated with methotrexate as the most common first line therapy in PsA. This cohort is the basis of a TWiCs (Trials Within Cohorts) study design and interventional studies will be nested within this in future. Whilst the cohort will receive treatment for their PsA as part of their routine clinical care, this treatment will be decided according to routine care and not protocolised.