Consensus exercise on domains in psoriatic arthritis.

Recent studies with biological therapy in psoriatic arthritis (PsA) have highlighted the need for validated and widely accepted assessment tools and outcome measures for this disease. A Delphi process was established through the CASPAR group where domains for assessment of PsA in clinical trials, longitudinal studies, and rehabilitation were identified. Although the process reduced the list of possible domains to approximately 12, it was not able to detect those that would be most important. Moreover, skin assessment was left out. A further study through the GRAPPA group subsequently identified the following domains: inflammation (peripheral joints, axial skeleton, physician global assessment), other features (dactylitis, enthesitis), skin and nails, imaging, biomarkers, and patient derived indices (pain, quality of life, itch, function), as important in the assessment of patients with PsA. These domains require further refining, and instruments to measure the items need to be developed.