Optimizing rheumatology referral in patients with psoriasis: a community-based pilot study of four screening questionnaires within a collaborative dermatology–rheumatology pathway

BACKGROUND: Musculoskeletal symptoms in patients with psoriasis may indicate psoriatic arthritis (PsA) or other rheumatic diseases requiring specialist assessment. Screening questionnaires may facilitate referral from dermatology to rheumatology, but their performance within collaborative community pathways remains uncertain. OBJECTIVES: To compare four psoriasis screening questionnaires for PsA and inflammatory arthritis (IA) within a community dermatology-rheumatology referral pathway and assess operational feasibility. METHODS: Fifty adults with dermatologist-confirmed psoriasis, no prior PsA, and no systemic psoriasis therapy were prospectively recruited to a cross-sectional diagnostic accuracy pilot study. PEST, EARP, PASE, and ToPAS II were completed before blinded rheumatological assessment. Sensitivity, specificity, PPV, NPV, 95% confidence intervals, and Youden index were calculated for PsA and IA using complete-case denominators. RESULTS: IA was identified in 13/50 participants (26.0%), including 10 with PsA (20.0%); OA and FMS occurred in 56.0% and 8.0%. Screen-positive rates ranged from 36.0% (PASE) to 64.0% (EARP). ToPAS II had the highest observed Youden index for IA (0.408; sensitivity 76.9%, specificity 63.9%) and PsA (0.290; 70.0%, 59.0%). Alternative or coexisting diagnoses were common among screen-positive participants. CONCLUSIONS: The pathway was operationally feasible within the two participating practices and identified previously unrecognized inflammatory rheumatic disease. ToPAS II showed the highest observed sensitivity-specificity balance, but small case numbers preclude definitive ranking. Alternative diagnoses among screen-positive participants support use of these questionnaires as triage instruments rather than diagnostic tests for PsA. Key Points • A community dermatology-rheumatology referral pathway was feasible in routine practice. • Rheumatological assessment identified inflammatory arthritis in 26% of participants. • In this pilot cohort, ToPAS II showed the highest observed sensitivity-specificity balance for inflammatoryarthritis and PsA, although definitive ranking was not possible. • Screening questionnaires should guide rheumatology referral rather than diagnose PsA alone.