Background There has been considerable research into clinical characteristics of nr-axSpA in western European or American population, but no data about Asian population.

Objectives To evaluate the clinical characteristics and outcomes of nonradiographic axial spondyloarthritis (nr-axSpA) in Korean patients.

Methods A retrospective analysis was performed of 155 patients with nr-axSpA at a single tertiary hospital between January 2001 and January 2011. Baseline characteristics and clinical courses of nr-axSpA were reviewed and compared with the ankylosing spondylitis (AS).

Results Fifty-two (33.5%) patients were female and mean disease duration was 61.4±46.1 months. In female, age at disease onset was older (33.4±11.4 vs 27.5±9.9 years, p=0.001) than male. When compared with AS, the mean age at symptom onset (29.5±10.8 vs 25.9±9.2, p<0.001) was older and male to female ratio (2:1 vs 5:1, p=0.001) was lower in patients with nr-axSpA. Among nr-axSpA, 29 (18.7%) patients progressed to AS during the follow-up period. The proportion of female was lower (14.3 vs 38.1%, p=0.015) and disease duration was significantly longer (106.1±37.1 vs 51.2±41.8 months, p<0.001) in patients with progressors than those of non-progressors. Minimal X-ray change at baseline was frequently found in progressors (69.0 vs 42.1%, p=0.009). Presence of syndesmophyte at baseline was a predictor for disease progression (HR 1.01, 95% CI 1.00-1.02, p=0.046).

Conclusions The male predominance is more prominent in Korean patients with SpA compared with Caucasians. Female nr-axSpA patients had late symptom onset and less progression to AS. Bony change at baseline was associated with disease progression.

Disclosure of Interest : None declared

DOI 10.1136/annrheumdis-2014-eular.3463