Enhanced surveillance for the detection of psoriatic arthritis in a UK primary care psoriasis population: results from the TUDOR trial

Background Our objective was to determine whether early detection of undiagnosed PsA in a primary care psoriasis population improves outcome in physical function at 24 months post-registration.Methods A multicentre, prospective, parallel group cluster randomized controlled trial in patients with psoriasis was conducted. Participants with suspected inflammatory arthritis on screening were referred for an assessment of PsA [enhanced surveillance (ES) arm: at baseline, and 12 and 24 months; standard care (SC) arm: at 24 months]. The primary outcome measure was the HAQ Disability Index (HAQ-DI) at 24 months post-registration in participants diagnosed with PsA.Results A total of 2225 participants across 135 general practitioner practices registered: 1123 allocated to ES and 1102 to SC. The primary analysis population consisted of 87 participants with a positive diagnosis of PsA: 64 in ES, 23 in SC. The adjusted odds ratio (OR) for achieving a HAQ-DI score of 0 at 24 months post-registration in ES compared with SC was 0.64 [95% CI (0.17, 2.38)], and the adjusted OR of achieving a higher (non-zero) HAQ-DI score at 24 months post-registration in ES relative to SC arm was 1.12 (95% CI 0.67, 1.86), indicating no evidence of a difference between the two treatment groups (P = 0.66).Conclusion The trial was underpowered for demonstrating the prespecified treatment effect; in patients with psoriasis there was no evidence that early diagnosis of PsA by ES in primary care changes physical function at 24 months compared with SC.Clinical trial registration The TUDOR trial is registered as ISRCTN38877516.