THU0263 Analysis on characteristics of 82 patients with ankylosing spondylitisin japan

Background Ankylosing spondylitis (AS) is the prototype of spondyloarthritis, which affects sacroiliac joints, spine, peripheral joints and enthuses. HLA-B27 is known to be related with AS and there is a considerable number of patients suffering from AS among other rheumatic diseases. In Japan, however, the prevalence of AS was reported to be less than 0.1% much lower than western countries and also other East Asian countries 1) 2) 3). This is due to the low frequency of HLA-B27 in Japanese (0.3%) compared to 5%–10% in the countries mentioned above. Because of small number of AS patients, clinical features and HLA-B27 positivity has not been well investigated in Japanese patients with AS. Since our hospital has an outpatient specialising in AS and there are many patients, we conducted a survey on AS Objectives In this study, we examined the characteristics of patients with AS in our hospital and compared the data of patients with AS in Japan and overseas. Methods We conducted a questionnaire survey on patients fulfilling the modified New York criteria for AS. A questionnaire included demographic data and histories. We also retrospectively investigated the data of blood test, radiographs and the presence of inflammatory back pain (IBP), HLA-B27, enthesitis, dactylitis, radiographic sacroiliitis and extra-articular manifestation. Results A total of 82 patients (82.9% male) including Japanese (68), Chinese,9 Korean5 with AS who fulfilled the modified New York criteria were enrolled from May in 2013 to April in 2016. Of 68 patients with HLA-B27 test result, 61 patients (89.7%) were HLA-B27 positive. Of 54 Japanese patients, 48 patients (88.9%) were HLA-B27 positive. IBP, enthesitis, dactylitis, bamboo spine and uveitis were found in 67 patients (81.7%), 31 patients (37.8%), 5 patients (6.1%), 44 patients (53.7%) and 30 patients (36.6%), respectively. Conclusions In Japanese AS patients, the prevalence of HLA-B27 was high (almost 90%) and other characteristics were similar with those of Western countries. In Japan where the frequency of HLA-B27 is very low, B27 positivity is considered to have high diagnostic value. References [1] Hukuda S, Minami M, Saito T, Spondyloarthropathies in Japan; Nationwide questionnaire survey performed by the japan ankylosing spondylitis society. J Rheumatol2001;28: 554–559. [2] Calin A, Fries JF. Striking prevalence of ankylosing spondylitis in “healthy” W27 positive males and gemales. N Engl J Med. 1975;293:835–839. [3] Akkoc N, Khan MA. Overestimation of the prevalence of ankylosing spondylitis in the Berlin study: comment on the article by Braun, et al. Arthritis Rheum2005;52–4048–4049. Disclosure of Interest None declared