Psoriatic arthritis (PsA) is a chronic condition that causes joint pain, swelling, and can also affect the skin. While many people improve with treatment, some continue to have active disease despite trying several medications. These patients are often described as having “difficult-to-manage (D2M),” “complex-to-manage (C2M),” and/or “treatment-refractory (TR)” PsA. Two major expert groups (GRAPPA and EULAR) have recently proposed definitions to help identify these patients, but it is unclear how these approaches compare in real-world practice.

In this study, we examined 630 adults with PsA receiving care at a large clinic in Toronto. Using these definitions, about 36% of patients were classified as C2M by GRAPPA, compared with about 19% classified as D2M by EULAR. Around 13% of patients were considered treatment-refractory by both definitions. Patients in the TR group had more active disease, higher levels of inflammation, and greater exposure to advanced therapies.

We also found that women and individuals with higher body weight were more commonly represented in these difficult-to-treat groups. Overall, the GRAPPA definition identified a larger group of patients, while the EULAR definition was more stringent. Despite these differences, both approaches successfully identified patients with a higher disease burden.

These findings highlight the importance of recognizing challenging PsA cases and may help guide more personalized and multidisciplinary care strategies.