Abstract
Objective This study aimed to investigate whether patients who present with psoriatic arthritis (PsA) before or concurrently with psoriasis exhibit different baseline characteristics and disease outcomes compared with patients with classical PsA, in whom psoriasis precedes PsA. We also characterized factors contributing to the onset of psoriasis in these patients.
Methods We included patients with PsA from an observational cohort and classified them into 3 groups: classical PsA (psoriasis diagnosed before PsA), concurrent disease (psoriasis and PsA diagnosed within 1 year), and antecedent PsA (PsA diagnosed > 1 year before psoriasis). We assessed the association between these groups and 2 outcomes: mean disease activity and the course of radiographic damage. We used multivariable linear regression to estimate the adjusted 5-year mean swollen joint count (SJC) and Cox proportional hazards regression to evaluate time to radiographic progression. Cox regression was also used to identify factors associated with psoriasis onset in the antecedent PsA group.
Results Of the 1702 patients studied, 1138 (66.86%) were classified as having classical PsA, 444 (26.09%) as having concurrent PsA, and 120 (7.05%) as having antecedent PsA. These groups differed in baseline demographic and PsA-related characteristics. Compared with 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 disease-modifying antirheumatic drug (bDMARD) use was associated with a reduced risk of developing psoriasis in the group with antecedent PsA.
Conclusion The relative order of psoriasis and PsA diagnosis does not significantly affect disease activity or radiographic progression. bDMARDs may influence the onset of psoriasis in patients with antecedent PsA.
