Axial and peripheral spondyloarthritis: does psoriasis influence the clinical expression and disease burden? Data from REGISPONSER registry.

Objective: To evaluate whether the presence of psoriasis influences the clinical expression, disease activity and disease burden in both axial and peripheral phenotypes of spondyloarthritis (SpA).

Methods: Patients from the Spanish REGISPONSER registry classified as having SpA according to the ESSG criteria were included. Patients were classified as psoriatic or non-psoriatic depending on the presence of cutaneous or nail psoriasis; thereafter, they were classified as having either axial [presence of radiographic sacroiliitis OR inflammatory back pain (IBP)] or peripheral phenotype (absence of radiographic sacroiliitis AND absence of IBP AND presence of peripheral involvement). Pair-wise univariate and multivariate analyses among the four groups (psoriatic/non-psoriatic axial phenotypes and psoriatic/non-psoriatic peripheral phenotypes) were performed with adjustment for treatment intake.

Results: A total of 2296 patients were included in the analysis. Among patients with axial phenotype, psoriasis was independently associated (P < 0.05) with HLA-B27+ [odds ratio (OR) 0.27], uveitis (OR 0.46), synovitis (ever) (OR 2.59), dactylitis (OR 2.78) and the use of conventional synthetic DMARDs (csDMARDs) (OR 1.47) in comparison with non-psoriatic patients. Among patients with peripheral phenotype and adjusting for csDMARD intake, psoriasis was independently associated with higher age at disease onset (OR 1.05), HLA-B27+ (OR 0.14) and heel enthesitis (OR 0.22). Higher scores for patient-reported outcomes and greater use of treatment at the time of the study visit were observed in psoriatic patients with either axial or peripheral phenotype.

Conclusion: These findings suggest that, among all patients with SpA, psoriasis is associated with differences in clinical expression of SpA, a greater disease burden and increased use of drugs.