Rheumatologists back distinct definitions for two PsA types

Psoriatic arthritis

By Amanda Cameron

9 Jul 2024

Most rheumatologists think difficult-to-treat and complex-to-manage psoriatic arthritis (PsA) should have distinct definitions that include objective signs of inflammation, according to a new survey by GRAPPA.

The international group surveyed members managing PsA patients as part of a project to define difficult-to-treat disease more precisely. It received completed questionnaires from 223 specialists, including 179 rheumatologists and 40 dermatologists.

Of these, 83% favoured establishing distinct definitions for difficult-to-treat (D2T) and complex-to-manage (C2M) PsA, with 91% supporting a definition of difficult-to-treat disease that includes objective signs of inflammation.

Specifically, around 50% of respondents thought persistently elevated acute phase reactants (erythrocyte sedimentation rate or C-reactive protein) should be used to indicate the presence of inflammation in difficult-to-treat PsA, and 70% suggested including imaging assessments such as ultrasound and MRI to back this up.

A full 94% agreed that ineffectiveness or loss of effect of multiple medications constitutes difficult-to-treat PsA, according to the findings published this month.

Less agreement over treatment failure criteria

However, there was a “considerable lack of consensus” over the criteria for treatment failure, especially regarding the number of therapies needed to classify PsA as difficult-to-treat, GRAPPA said. 

While 67% of respondents thought the definition should include the failure of at least one conventional synthetic disease-modifying anti-rheumatic drug (DMARD), 79% preferred a definition based on failure of biological- or targeted-synthetic-DMARDs with different mechanisms of action.

The most popular definition included at least one conventional synthetic DMARD and at least two biological- or targeted-synthetic-DMARDs with different mechanisms of action, but this was endorsed by only 42% of respondents.

“These findings suggest a need for continued discussion to reach a more unified approach in defining difficult-to-treat-PsA, reflecting the complexity of the condition,” GRAPPA concluded.

Differing disease domains

When describing difficult-to-treat PsA, respondents most commonly mentioned enthesitis, arthritis, axial disease, dactylitis and skin/nail issues, but with complex-to-manage PsA, the emphasis shifted to factors like depression/anxiety, chronic pain, fatigue, other comorbidities and inflammatory bowel disease.

The importance of drug intolerance and treatment non-adherence for defining a case as complex-to-manage was also highlighted in the survey results.

GRAPPA noted that a key theme of the findings was that difficult-to-treat and complex-to-manage PsA are not mutually exclusive.

“Specifically, some experts view D2T-PsA as a subset within the broader category of C2M-PsA,” the group said. “This understanding underscores the concept that D2T-PsA represents a truly treatment refractory group that belongs to the wider C2M-PsA spectrum, requiring different approaches and considerations for effective management.”

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