Abstract
BACKGROUND: Although thyroid eye disease (TED) can impact social and psychological well-being, the epidemiological evidence of TED is lacking in Japan. METHODS: Nationwide claims databases provided by JMDC Inc. and Medical Data Vision Co., Ltd. and national population statistics are used. Three TED definitions ranging from a strict definition only including a TED diagnosis to a broad definition including a TED diagnosis and considering ocular symptoms are considered. The proportion of patients by severity and disease activity are estimated based on definitions that would allow identification of those patients within the claims data. RESULTS: The incidence rate per 100 000 person-years ranged from 7.3 to 11.1 for the strict and broad TED definitions, respectively. For fiscal year 2020 (April 2020 to March 2021) the prevalence rate ranged between 24.65 (strict TED) and 37.58 (broad TED) per 100 000 persons. These correspond to 25 383 and 38 697 patients for the strict and broad TED definitions, respectively. Regardless of the definition used, a predominance of female patients was observed, and the highest burden of the disease was seen in the age group of 35 to 59. Mild and inactive forms of TED were predominant (about 85% and 74%, respectively). CONCLUSION: The incidence and prevalence of TED in Japan were 7.3 to 11.1 per 100 000 person-years and 24.65 to 37.58 per 100 000 persons, respectively. The robust results of this database study add valuable real-world evidence on the incidence and prevalence of TED in Japan.