Background:The epidemiology and clinical features of thromboangiitis obliterans (TAO) in Japan have not been updated extensively.

Methods and Results:This retrospective study used the Japanese Ministry of Health, Labour and Welfare (JMHLW) medical support system database and associated health insurance data. The number of medical financial support recipients registered as TAO patients and estimated prevalence of TAO decreased from fiscal year (FY) 2000 (10,089 and 7.95 [95% confidence interval, CI: 7.79–8.10] per 100,000 population) to FY 2010 (7,147 and 5.58 [95% Cl: 5.45–5.71] per 100,000) and leveled off until 2014. The prevalence of TAO among patients with peripheral arterial occlusive diseases declined from 7.15% (95% Cl: 7.00–7.31) in FY 2008 to 6.12% (95% Cl: 5.98–6.26) in FY 2014. Clinicodemographic features were obtained from 89 new recipients in FY 2013 and 2014: 12 (13%) women, 36 (40%) aged ≥50 years, 26 (29%) had probable onset age ≥50 years, 7 (8%) were non-smokers, and 12 (13%) had arteriosclerosis-related comorbidities. The symptoms were similar regardless of registration age, smoking history, or sex. Although 40 (45%) had digit ulcers, only 12 (13%) fulfilled Shionoya’s criteria. They rarely had infrapopliteal lesions combined with upper extremity involvement or phlebitis.

Conclusions:The prevalence of TAO has decreased in Japan. In the current diagnosis of TAO, various clinical characteristics including late onset, arteriosclerotic factors, non-smoking, or mild symptoms should be considered.