Yoshizawa Kaname, Joshita Satoru, Matsumoto Akihiro, Umemura Takeji, Tanaka Eiji, Morita Susumu, Maejima Toshitaka, Ota Masao
Departments of Gastroenterology, National Hospital Organization, Shinshu Ueda Medical Center.
Departments of Medicine, Shinshu University School of Medicine.
Hepatol Res. 2016 Aug;46(9):878-83. doi: 10.1111/hepr.12639. Epub 2016 Jan 11.
Although autoimmune hepatitis (AIH) is considered to be rare in Japan, precise data on the incidence and prevalence of this disease are scarce due to the lack of a nationwide registry. We therefore conducted a study of these factors over a secondary medical care area.
We retrospectively investigated the medical records of AIH patients seen during 2004-2009 and prospectively recruited subjects from 2010 to 2014 at our hospital. We surveyed via written questionnaires to all family doctors and hospitals in our secondary medical care area of Ueda, with a population 187 205 individuals over 14 years of age. We also surveyed several core liver disease hospitals in the areas neighboring Ueda.
Forty-eight patients with AIH were diagnosed between 2004 and 2014. AIH with histological features of acute hepatitis was increased. The average annual incidence of AIH in the area was 2.23 (age-standardized to the Japanese population). Forty-eight patients (37 patients diagnosed between 2004 and 2014, and 11 patients before 2003) were followed to the study end-point. The prevalence was 23.4 (age-standardized to the Japanese population) on 31 December 2014. After age-standardization to the World Health Organization world standard population, the incidence and prevalence of AIH decreased to 1.52 and 15.0, respectively, likely due to the high proportion of elderly patients in Japan.
The incidence and prevalence of AIH in Japan may be higher than previously believed due to increased awareness among family doctors, and a rise in the diagnosis of mild or atypical AIH.
尽管自身免疫性肝炎（AIH）在日本被认为较为罕见，但由于缺乏全国性登记系统，关于该疾病发病率和患病率的精确数据十分匮乏。因此，我们在一个二级医疗保健区域对这些因素展开了研究。
我们回顾性调查了2004年至2009年期间诊治的AIH患者的病历，并于2010年至2014年在我院前瞻性招募研究对象。我们通过书面问卷对位于上田的二级医疗保健区域内所有家庭医生和医院进行了调查，该区域有187205名14岁以上的居民。我们还对上田周边地区的几家核心肝病医院进行了调查。
2004年至2014年间共诊断出48例AIH患者。具有急性肝炎组织学特征的AIH有所增加。该地区AIH的年均发病率为2.23（根据日本人群进行年龄标准化）。48例患者（2004年至2014年间诊断出的37例患者以及2003年之前诊断出的11例患者）被随访至研究终点。2014年12月31日的患病率为23.4（根据日本人群进行年龄标准化）。在根据世界卫生组织世界标准人群进行年龄标准化后，AIH的发病率和患病率分别降至1.52和15.0，这可能是由于日本老年患者比例较高所致。
由于家庭医生的意识提高以及轻度或非典型AIH诊断率的上升，日本AIH的发病率和患病率可能高于此前的认知。
