Medical Cost and Prevalence of Mental Diseases across Different Health Insurance Systems in Japan


■ 学会名

■ 発表日

■ 筆頭演者
Kosuke Iwasaki
Milliman, Inc., Tokyo, Japan

■ 共同演者
Chise Ha¹, Tomomi Takeshima¹, Yumi Sato², Ikumi Nishi², Manami Yoshida², Shinzo Hiroi², Takumi Sugiyama³, Gen Terashima³, Akiko Hatakama⁴, Ataru Igarashi⁵,⁶
1) Milliman, Inc., Tokyo, Japan
2) Shionogi & Co., Ltd., Tokyo, Japan
3) JMDC Inc, Tokyo, Japan
4) DeSC Healthcare, Tokyo, Japan
5) The University of Tokyo, Tokyo, Japan.
6) Yokohama City University, Kanagawa, Japan.

■ 発表形態

■ 要旨
Japanese citizens are ensured the universal access to affordable healthcare owing to compulsory insurance system mainly consisting of employee-based health insurance (EHI) for employees in mid-large companies and their families and the citizens’ health insurance (NHI) for non-/self-employed workers. Our previous claims databases study revealed EHI and NHI differ in prevalence and medical costs of diseases, especially for mental diseases. Thus, we focused on mental diseases in this study to explore the difference between EHI and NHI.

JMDC database covering EHI data and DeSC database covering EHI and NHI data were used. For mental diseases, age- and gender-specific prevalence and medical costs per-member-per-month were calculated. Costs per-member-per-month was calculated for schizophrenia and depression as well as inpatients, outpatients, and prescriptions.

During the study period, 13,665,051 patients were in JMDC, 908,237 in DeSC-EHI, and 7,147,428 in NHI. In 2020, prevalence or costs of mental diseases in female and male aged ≤24 years was not substantially different between EHI and NHI. In female aged ≥25 years, NHI was highest in prevalence and costs followed by EHI-family and EHI-employee in order (prevalence: 15.9 %, 9.5%, 8.8% in 40-44 years old, respectively) whereas EHI-family was the highest in male aged >25 years, followed by NHI and EHI-employee (prevalence: 26.5%, 13.6%, 7.5% in 40-44 years old, respectively). More than 60% of the difference in costs was attributable to treatment costs of schizophrenia, while 21% and 29% to depression in female and male, respectively. Patients of schizophrenia or depression were hospitalized for >1 year more frequently in NHI.

Prevalence and costs of mental diseases were higher in NHI. Patients of schizophrenia or depression who stayed in hospital for more than a year pushed up the overall costs.