The Pattern of Musculoskeletal Complaints in Patients With Suspected Psoriatic Arthritis and Their Correlation With Physical Examination and Ultrasound

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 x 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 (kappa = 0.28). The lowest levels of agreement were found between ultrasound and patient (kappa = 0.08) and physiotherapist and ultrasound (kappa = 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.