Epidemiological and clinical insights into Behçet's disease in Japan: a 2019 nationwide analysis

To clarify contemporary epidemiological and clinical trends of Behçet's disease in Japan by analysing the 2019 National Database of Designated Intractable Diseases (MHLW), describing patient demographics, organ involvement, impact on daily life, and treatment patterns.

This study analysed the 2019 data from the National Database of Designated Intractable Diseases of Japan, provided by the Japanese Ministry of Health, Labour and Welfare. We focused on age distribution, symptom frequency, daily life impact, and treatment trends.

In the 2019 database, 10 406 patients with BD were registered. The median age was 55 years, with a higher proportion of women affected (53.2%). Serious manifestations such as ocular, vascular, and central nervous system involvement were more frequent in males, whereas females showed more mucocutaneous and articular symptoms, representing mild forms of the disease. Pharmacological treatment was common (93.8%), with corticosteroids (44.3%), colchicine (50.9%), infliximab (17.0%), and adalimumab (9.6%) being frequently used. BD significantly affected daily life, with nearly one-third experiencing impaired mobility or depression.

This nationwide analysis highlighted sex-based differences in clinical features and found that BD continues to substantially affect quality of life. The widespread use of biologics suggests a shift in therapeutic strategies.