Psoriatic arthritis (PsA) is a multidimensional inflammatory disease for which multiple outcome measures can be used to assess disease activity. In 2006, the OMERACT has proposed the first core domain set in PsA. Since 2006, much work has been performed on outcome measures in PsA.
The purpose of this study was to assess outcome measures collected in recent PsA registries or longitudinal cohorts.
A systematic literature review was performed in Pubmed Medline (PROSPERO CRD42020175745) to identify all articles reporting on either registries or longitudinal cohorts in PsA, published between 2010 and March 2020. Registries centered on drugs or not PsA-specific, trials and long-term extension studies were excluded. The data collection comprised patient characteristics and the clinical outcome measures reported, including composite scores and patient reported outcomes (PROs). Statistics were descriptive.
Of 673 articles, 73 were analysed, reporting on 27 registries/cohorts. Overall, 16,183 patients were included, with a mean of 599 per study; 51% were men, weighted mean age was 49.7 ± 9.3 years and weighted mean disease duration was 6.8 ± 0.2 years. Overall, 58 different outcome measures were collected. Disease activity composite scores were used in 20/27 (74%) registries through 8 different scores (most frequently Minimal Disease Activity: 41%, DAS28: 33% and DAPSA: 30%). Among the domains of PsA, joint involvement was reported in 26/27 (96%) registries (through the 66/68 joint count: 85%) and skin psoriasis in 93% (through PASI: 72%), whereas enthesitis, dactylitis and axial involvement were less often reported (respectively, 77%, 74% and 52%). Furthermore, 22/27 (82%) studies reported HAQ; the other frequently reported PROs were patient global assessment (70%) and pain (63%).
Data collection in PsA is very heterogeneous, reflecting the need for international consensus on outcome measures.