Objective: To describe the pattern of musculoskeletal (MSK) symptoms and their correlation with clinical and sonographic findings among psoriasis patients with suspected psoriatic arthritis (PsA).
Methods: Patients with psoriasis and no prior diagnosis of PsA were referred for assessment of their MSK complaints. The study included the following steps: (1) assessment by an advanced practice physiotherapist, (2) targeted MSK ultrasound, and (3) assessment by a rheumatologist. In addition, patients were asked to complete questionnaires about the nature and duration of their MSK symptoms and to mark the location of their painful joints on a homunculus. Each patient was classified by a rheumatologist as "Not PsA," "Possible PsA," or "PsA". MSK symptoms and patient-reported outcomes (PRO) were compared between patients with PsA and Possible/Not PsA. Agreement between modalities was assessed using κ statistics.
Results: Two hundred three patients with psoriasis and MK symptoms were enrolled (8.8% PsA, 23.6% Possible PsA). Patients classified as PsA had worse scores on the PsA Impact of Disease (P = 0.004) and Functional Assessment of Chronic Illness Therapy-Fatigue scale (P = 0.02). There was no difference between the 2 groups in the presence, distribution, and duration of MSK symptoms. Analysis of agreement in physical examination between modalities revealed the strongest agreement between the rheumatologist and physiotherapist (κ = 0.28). The lowest levels of agreement were found between ultrasound and patient (κ = 0.08) and physiotherapist and ultrasound (κ = 0.08).
Conclusion: The results of this study suggest that the intensity, rather than the type, duration, or distribution of MSK symptoms, is associated with PsA among patients with psoriasis.
Keywords: diagnostic tools; psoriasis; psoriatic arthritis; ultrasound.
Copyright © 2021 by the Journal of Rheumatology.