Characteristics of late-onset spondyloarthritis in Japan: A retrospective cohort study.

Spondyloarthritis may be increasingly present in older patients as life expectancy increases. We investigated clinical differences between early-onset and late-onset spondyloarthritis in Japan.We retrospectively reviewed 114 patients consecutively diagnosed with spondyloarthritis. The clinical course of each patient was observed for ≥1 year. We defined early-onset and late-onset spondyloarthritis as <57 or ≥57 years at a median age of this study group, respectively. We compared clinical characteristics between these 2 groups.Disease duration was significantly shorter before diagnosis in the late-onset group (P < .01). Inflammatory back pain (IBP) was significantly more common in the early-onset group (P < .01), whereas dactylitis frequency was significantly higher in the late-onset group. Significantly more patients with early-onset spondyloarthritis were human leukocyte antigen (HLA) B27-positive (P < .01). Articular synovitis, particularly of the wrist, was significantly more common on power Doppler ultrasound (PDUS) in the late-onset group (P < .01). Tenosynovitis or peritendinitis, particularly in the finger and wrist flexors were also more frequent in the late-onset group (P < .001 and P < .05, respectively). Enthesitis of the finger collateral ligament and lateral collateral ligament were significantly more common in the late-onset group (both P < .05). Multiple logistic regression analysis revealed that, comparatively, IBP was significantly and independently much more likely to occur in the early-onset group.The patients with late-onset spondyloarthritis had a lower frequency of IBP and HLA B27 and a higher frequency of dactylitis and PDUS findings in peripheral involvement.