Key clinical point: Oligoarticular psoriatic arthritis (PsA) is similar to polyarticular disease. However, involvement of lower extremity small joint had the highest chances of polyarticular presentation, whereas low Short Form-36 (SF-36) Mental Component Summary (MCS) score was significantly associated with progression from oligoarthritis to polyarthritis.
Major finding: Demographics and clinical characteristics were similar between the oligoarticular and polyarticular PsA groups. However, polyarticular PsA was associated with higher odds of lower extremity small joints (odds ratio, 17.15; P < .001). Among patients with oligoarticular PsA, 39% developed polyarticular PsA with lower SF-36 MCS being the only predictor for progression (hazard ratio, 0.97; P = .01).
Study details: Findings are from a longitudinal study including 407 patients with PsA who entered the University of Toronto PsA clinic within 12 months of diagnosis between 1978 and 2018, of which 47% presented with oligoarthritis and 53% with polyarthritis.
Disclosures: The University of Toronto PsA program was funded by the Krembil Foundation. The authors declared no conflict of interests.
Source: Gladman DD et al. J Rheumatol. 2021 Aug 1. doi: 10.3899/jrheum.210434 .