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 psoriatic arthritis (PsA) in a primary care psoriasis population improves outcome in physical function at 24 months post-registration.

Methods: A multicentre, prospective, parallel group cluster randomised 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, 12 and 24 months; standard care (SC) arm: at 24 months). The primary outcome measure was the Health Assessment Questionnaire Disability Index (HAQ-DI) at 24 months post registration in participants diagnosed with PsA.

Results: A total of 2225 participants across 135 GP 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.