Clinical characteristics of peripheral joint disease in axial and peripheral spondyloarthritis: findings from a multicentre cross-sectional study

Peripheral joint disease (PJD) is the most common peripheral manifestation in spondyloarthritis (SpA) patients. This study aimed to determine PJD characteristics and associated factors in patients with axial SpA (AxSpA) and peripheral SpA (pSpA). This cross-sectional and multicenter study involved 13 different rheumatology and physical medicine & rehabilitation clinics, and patients diagnosed with axSpA or pSpA were included in the study. PJD was defined as the ‘ever’ related to SpA according to the physician. Multivariable analyses were conducted to identify factors associated with PJD. A total of 394 patients were enrolled in the study (57.6% male, mean age 40.8 years), of whom 359 (91.1%) were classified as AxSpA and 35 (8.9%) as pSpA. Peripheral arthritis was reported in 118 patients (29.9%), comprising 85 (72%) with AxSpA and 33 (28%) with pSpA. Among the whole population with PJD, the main joint involvement pattern was monoarticular (33.9%, n = 40) and oligoarticular (49.2%, n = 58). The rate of predominantly lower limb and large joint involvement was approximately 60% (n = 68) and the major course of PJD was transient (42.4%, n = 50) and intermittent (40.7%, n = 48). pSpA patients had a higher rate of persistent (33.3% vs. 14.3%, p = 0.021) and progressive arthritis (15.2% vs. 1.2%, p = 0.007). The coexistence of PJD with other peripheral involvement and extra-articular manifestations excluding psoriasis was widespread. Dactylitis, enthesitis, and high CRP level were positively associated with PJD; on the contrary, ever alcohol intake, presence of sacroiliitis on MRI, and family history for SpA were negatively associated. PJD was accompanied by both other peripheral involvements and extra-articular manifestations, excluding psoriasis and the course of PJD was more persistent in pSpA patients. This undoubtedly contributes to an increased disease burden.