Swollen Joint Count Questioned in Moderate, Oligoarticular Psoriatic Arthritis

In psoriatic arthritis (PsA), while swollen joint count remains a key assessment when defining oligoarticular and moderate disease, joint location and functional impairment are also considered when describing the disease as moderate, according to a study published in the Journal of Rheumatology.¹

Speaking to Rheumatology Network, corresponding author Dafna D. Gladman, MD, FRCPC, a professor of Medicine at the University of Toronto, said that “the reason for doing this study was the requirement for at least 5 swollen joints for approval for advanced therapy in patients with PsA.” Dr Gladman added that “rheumatologists consider the site and functional limitation of the affected joints more than the actual number of joints involved. Therefore, the requirement by many providers for a minimum of 5 swollen joints is likely inappropriate.”

Clinical trials generally focus on polyarticular PsA and an unmet need exists for an effective treatment for patients with oligoarticular disease. Patients with articular symptoms are usually treated with non-steroidal anti-inflammatory drugs, corticosteroid injections, and disease-modifying anti-rheumatic drugs, with biologic options recommended for those with polyarticular or severe PsA.

Dr. Gladman and colleagues used an online survey to determine rheumatologists’ perspectives on the definition and treatment of oligoarticular and moderate PsA. A total of 64 rheumatologists responded from 6 Canadian provinces. Nearly half of respondents were in practice for more than 20 years.

A majority of surveyed rheumatologists reported swollen joint count as the measure they have used when defining moderate PsA, along with tender joint count, enthesitis, dactylitis, work productivity, patient perception, and HAQ score. Of the rheumatologists, 86.4% and 96.7% using swollen joint count to describe moderate PsA and oligoarticular PsA, respectively, while also considering location of inflammation in PsA assessments.

When specifying the lower and upper swollen joint count cutoff scores for defining moderate PsA, the rheumatologists reported a wide range of scores, which the authors said suggests a lack of an agreed-upon definition for moderate PsA.

“Moderate PsA is defined not only by swollen joint count, but also encompasses other manifestations of PsA, their relative severity, and impact on patients. Oligoarticular PsA is defined primarily by joint count with reduced emphasis on severity of other manifestations,” stated investigators. “This discrepancy suggests a need to decouple treatment access from joint count and instead focus on the impact on individual patients, which includes assessing for all features of PsA, as well as patient-reported outcome measures.”

Further, 68% of rheumatologists identified access to treatment as the greatest challenge with oligoarticular PsA, more so than comorbidities, patient acceptance, treatment choices, diagnosis, when to initiate treatment, and lack of treatment.

Reference:

Gladman, DD, Starr, M, Cividino, A, et al. Canadian Rheumatologists' Perspectives on Moderate Psoriatic Arthritis and Oligoarticular Psoriatic Arthritis. [published online ahead of print, 2021 May 15]. J Rheumatol. 2021;jrheum.201195. doi:10.3899/jrheum.201195