Do Patients Diagnosed with Psoriatic Arthritis Before or Concurrently with Psoriasis Have Different Disease Phenotype and Outcomes?

Abstract

We aimed to investigate whether patients who present with psoriatic arthritis (PsA) before or concurrently with psoriasis exhibit different baseline characteristics and disease outcomes compared to those with classical PsA, where psoriasis precedes PsA. We also characterized factors contributing to the onset of psoriasis in these patients. We included PsA patients from an observational cohort and classified them into three groups: classical PsA (psoriasis diagnosis before PsA), concurrent disease (diagnosis of psoriasis and PsA within one year), and antecedent PsA (diagnosed >1 year before psoriasis). We assessed the association between these groups and two outcomes: average disease activity and course of radiographic damage. We employed multivariable linear regression for the five-year adjusted mean swollen joint count (SJC) from clinic entry and Cox regression for time to radiographic progression. We also used Cox regression to explore associations with psoriasis onset in the antecedent PsA group. Of the 1,702 studied patients, 1,138 (66.86%) were classified as having classical PsA, 444 (26.09%) as concurrent PsA, and 120 (7.05%) as antecedent PsA. These groups differed in baseline demographic and PsA-related characteristics. Compared to patients with classical PsA, those with concurrent or antecedent PsA showed no significant differences in time-averaged disease activity or time to radiographic progression. Biologic DMARD use was associated with a reduced risk of developing psoriasis in this group. The relative order of psoriasis and PsA diagnosis does not significantly impact disease activity or radiographic progression. Biologic DMARDs may influence the onset of psoriasis in patients with antecedent PsA.