The study aimed to identify the optimal combination of triage methods to identify PsA among psoriasis patients with musculoskeletal symptoms in a rapid access clinic and to describe their outcome after 1 year.
Patients with psoriasis and no prior diagnosis of PsA were referred for assessment of their musculoskeletal complaints. Each patient was assessed by the following three triage modalities: 1) assessment by an advanced practice physiotherapist; 2) targeted musculoskeletal ultrasound (MSK-US) and; 3) PsA screening questionnaires. The patients were then evaluated by a rheumatologist who determined their disease status and classified them as: "Not PsA", "Possibly PsA" or "PsA". Patients returned for a one year follow up visit and were re-assessed for change in their disease status. Sensitivity and specificity were calculated for each individual modality as well as for combinations of modalities.
203 patients with psoriasis and musculoskeletal symptoms were enrolled. 8.8% were classified as PsA and 23.6% as possibly PsA. There was no significant difference in the individual performance of the modalities. The highest sensitivity was seen with MSK-US (89%) and the highest specificity was found with the Psoriatic Arthritis Screening and Evaluation (PASE) questionnaire (79%). The addition of MSK-US data improved the performance of the modalities. A total of 9 patients converted to PsA after 1 year. All patient reported outcome measures have significantly improved at one year (P<0.001).
Combining MSK-US with a screening questionnaire for PsA improved the triage of patients with suspected PsA.