Physician- vs Questionnaire-Based Screening for Psoriatic Arthritis in Psoriasis

Early diagnosis of psoriatic arthritis (PsA) requires close collaboration between dermatologists (as the skin manifestations of psoriatic disease in most cases precede the musculoskeletal manifestations) and rheumatologists (who are usually responsible for the final diagnosis of PsA and treatment of the musculoskeletal manifestations). Previous epidemiological studies suggest that there may still be a significant proportion of undiagnosed PsA patients among those with psoriasis seen by a dermatologist. At the same time, a diagnostic delay of more than 6 months contributes to poor radiological and functional outcomes in PsA patients. Several screening tools / questionnaires (including the Psoriatic Arthritis Screening Evaluation - PASE, the Toronto Psoriatic Arthritis Screen - ToPAS and its further development - TOPAS 2, the Psoriasis Epidemiology Screening Tool - PEST, and the Early Psoriatic Arthritis Screening Questionnaire - EARP) have been developed and validated in the past decades - all relying mostly on symptoms reported by a patient with psoriasis without an evaluation / confirmation of the presence of musculoskeletal symptoms by a dermatologist. The CONTEST study, which compared three screening tools (PASE, ToPAS and PEST) in a secondary care setting, determined that they all had a good probability of detecting PsA (sensitivity of approximately 80%) but had poor specificity (approximately 35%). Further analysis of the results of the above study has identified the most discriminative questions from each of the three questionnaires, including questions about the back and neck, and these items have been combined to create a new single 8-item screening questionnaire (CONTEST). However, a subsequent study demonstrated a similar performance for the CONTEST and the PEST tools. This poor specificity means that screening questionnaires are often not used in practice and raises a risk of overwhelming rheumatology referrals. In a recent survey of GRAPPA members, most