ULTRASOUND imaging may offer a more precise way to distinguish between inflammatory and non-inflammatory phenotypes in patients with difficult-to-treat psoriatic arthritis (D2T-PsA), according to new multicenter cross-sectional study findings. The classification could guide more targeted treatment strategies for patients who fail to respond to multiple advanced therapies.
Researchers assessed 517 patients with psoriatic arthritis receiving biological or targeted synthetic disease-modifying anti-rheumatic drugs (b/tsDMARDs). D2T-PsA was defined as persistent disease activity despite trials of at least two different b/tsDMARD classes, with a Disease Activity in Psoriatic Arthritis (DAPSA) score over 14. Of the cohort, 53 patients (10.3%) met these criteria.
Using a combination of clinical evaluation and musculoskeletal ultrasound (MSUS), the team identified two distinct subgroups: persistent inflammatory PsA (PIPsA, 57%) and non-inflammatory PsA (NIPsA, 43%). Patients with PIPsA showed more objective signs of joint inflammation, including a higher median swollen joint count, increased rates of dactylitis and nail psoriasis, and greater ultrasound evidence of synovitis and structural damage.
By contrast, NIPsA patients exhibited higher tender point counts, greater patient–physician global assessment discrepancies, and higher enthesitis scores, suggesting pain mechanisms beyond active joint inflammation. Ultrasound findings in this group indicated lower inflammatory activity but still revealed structural joint changes.
The authors note that these phenotype distinctions, based on readily detectable clinical and imaging features, may help rheumatologists better tailor treatment approaches. For PIPsA, therapies aimed at controlling inflammation may be prioritized, while NIPsA patients might benefit from strategies targeting pain modulation and functional improvement.
These findings underscore the potential of integrating MSUS into routine assessment for patients with refractory psoriatic arthritis, helping to clarify the underlying drivers of symptoms and reduce trial-and-error prescribing.
Reference:
Zabotti A et al. Using ultrasound to define inflammatory and non-inflammatory phenotypes in difficult-to-treat psoriatic arthritis. RMD Open. 2025;11(3):e005785
