Multicentre ObservatioNal Initiative in Treat to Target Outcomes in Psoriatic Arthritis

MONITOR is a cohort study recruiting patients with a new diagnosis of psoriatic arthritis (PsA) which will establish outcomes using a pragmatic feasible 'treat to target' approach in a real-life clinic population. It is the central cohort for a planned Trials Within Cohorts (TWiCs) design which will test alternative therapies and interventions in embedded clinical trials comparing outcomes to those receiving "standard care" in the cohort.

Inclusion Criteria: * Participant is willing and able to give informed consent for participation in the study. * Male or Female * Aged 18 years or above. * Clinical diagnosis of PsA based upon the Classification of PsA (CASPAR) criteria(23)) * Active PsA defined by ≥1 tender or ≥1 swollen joint or ≥1 enthesis (site of attachment of tendon to bone) * Not previously received treatment with synthetic or biologic disease-modifying anti-rheumatic drugs (DMARDs) for their articular disease. * In the Investigator's opinion, is able and willing to comply with all study requirements. Exclusion Criteria: * Current or previous treatment of arthritis with synthetic DMARDs (including methotrexate, leflunomide or sulfasalazine) or biologic DMARDs (including tumour necrosis factor (TNF), interleukin (IL)12/23 or IL17 inhibitor therapies) or targeted synthetic DMARDs (phosphodiesterase (PDE) 4 or Janus kinase (JAK) inhibitor therapies). * Use of investigational therapies within 1 month or 5 biological half-lives of the baseline study visit(whichever is longer) * Women who are pregnant, nursing or planning pregnancy during the following 12 months.