Understanding difficult-to-treat psoriatic arthritis: Data from the Rheumatic Diseases Portuguese Registry

Area of Science:

• Rheumatology
• Immunology
• Clinical Medicine

Background:

• Psoriatic arthritis (PsA) is a chronic inflammatory condition.
• Identifying difficult-to-treat (D2T) PsA is crucial for optimizing patient outcomes.
• Current understanding of D2T PsA prevalence and predictors requires further investigation.

Purpose of the Study:

• To estimate the proportion of patients with difficult-to-treat psoriatic arthritis (D2T PsA).
• To identify clinical and demographic predictors associated with D2T PsA.
• To inform clinical practice and future research directions for managing challenging PsA cases.

Main Methods:

• A multicentre observational retrospective study utilizing data from the Rheumatic Diseases Portuguese Registry (Reuma.pt).
• Two distinct definitions were employed to classify D2T PsA based on treatment failure (≥2 or ≥3 b/tsDMARDs with different MoAs) and active/progressive disease signs.
• Statistical analysis was performed to identify associated predictors.

Main Results:

• The study included 1873 patients, with D2T PsA proportions of 3.7% and 0.9% based on the two definitions.
• D2T PsA was significantly associated with younger age at onset/diagnosis, polyarticular phenotype, depression, enthesitis, and lower BMI.
• Patients with D2T PsA exhibited higher baseline tender/swollen joint counts and DAPSA scores, along with increased rates of treatment discontinuation.

Conclusions:

• The prevalence of D2T PsA ranges from 0.9% to 3.7%.
• Key predictors of D2T PsA include polyarticular disease, higher baseline swollen joint count, and longer treatment duration on initial b/tsDMARDs.
• D2T PsA patients present with greater disease activity prior to first-line biologic/targeted synthetic DMARDs initiation and experience higher treatment discontinuation rates.