Musculoskeletal Ultrasonography Can Aid Earlier Diagnosis of Psoriatic Arthritis

While the correlation between musculoskeletal symptoms, patient-reported outcomes, and ultrasonography findings is poor in patients with psoriasis with suspected psoriatic arthritis (PsA), musculoskeletal ultrasonography (MSK-US) provides additional information for clinical assessment and aids in earlier diagnosis of PsA, according to findings of a new study presented at the 2019 American College of Rheumatology /Association of Rheumatology Professionals Annual Meeting.

Data are limited on the variety of musculoskeletal symptoms experienced by patients with early PsA. Lihi Eder, MD, PhD, a scientist at the Women’s College Research Institute at the Women’s College Hospital in Toronto, Canada, and colleagues evaluated data of 203 patients with psoriasis and musculoskeletal symptoms without a prior diagnosis of PsA.

The researchers evaluated patients in a rapid access clinic with a central triage system that used the following modalities: screening questionnaires with homunculus where patients marked the location of the affected joints; assessment by an advanced-practice physiotherapist; and MSK-US of joints and entheses. Patients completed questionnaires about the nature and duration of their musculoskeletal symptoms, physical function, and quality of life.

Patients were classified by a rheumatologist as PsA, possible PsA, or not PsA. A total of 18 patients (8.8%) were classified as PsA, and 48 patients (23.6%) were classified as possible PsA. Patients with PsA had higher intensity of musculoskeletal and skin-related symptoms via the Dermatology Life Quality Index and worse scores in domains such as physical function, quality of life, and fatigue. “The intensity, rather than the type, duration or distribution of musculoskeletal symptoms, is associated with psoriatic arthritis among patients with psoriasis,” the researchers wrote.

Analysis of agreement between modalities showed the strongest agreement between the rheumatologist and physiotherapist. The lowest levels of agreement were observed between the patient and ultrasonography, as well as the physiotherapist and ultrasonography.

“MSK-USprovides additional information to the clinical assessment and aid in diagnosing PsA patients at earlier stages,” the researchers concluded. —Melinda Stevens