Difficult-to-manage psoriatic arthritis: Prevalence, phenotype, and clinical burden in real-world practice: insights from the SCQM registry

To apply consensus-based, difficult-to-treat definitions of psoriatic arthritis (PsA) and to investigate the prevalence, demographics, and clinical characteristics of difficult-to-manage (D2M)/complex-to-manage (C2M) and treatment-refractory (TR) PsA.

Retrospective analysis of data derived from the prospective, multicentre, longitudinal Swiss registry was conducted. Patients were eligible if they initiated their advanced therapy after inclusion in the registry and had ≥12 months of follow-up. Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) and European Alliance of Associations for Rheumatology (EULAR) definitions were applied to identify cases of C2M/D2M and TR.

From 2493 patients, 30.4% / 2.6% fulfilled the GRAPPA criteria for C2M/TR disease, while 17% / 7.3% met the D2M/TR EULAR criteria, respectively. At baseline, C2M/D2M patients were more frequently women (p < 0.001), smokers, had higher body mass index (BMI), and presented more comorbidities. C2M/D2M patients also demonstrated higher inflammatory markers, higher prevalence of enthesitis, more axial involvement, more severe psoriasis, and worse disease activity scores compared with non-C2M/non-D2M patients (p ≤ 0.001). However, there were no significant differences regarding the prevalence of HLA-B27, dactylitis, nail disease, or other extra-musculoskeletal manifestations. Within both criteria, the TR subgroup showed higher BMI, swollen joint counts, and tender entheses. D2M-TR patients showed significant differences regarding the inflammatory markers, quality of life, and disease activity measures, compared to non-TR D2M patients (p < 0.05).

Applying the GRAPPA and EULAR definitions in a large real-world cohort identified distinct clinical and inflammatory profiles in the C2M/D2M and TR groups, highlighting the need for phenotype-tailored management strategies.