Japan Research Institute Announces Report Proposing Medical Collaboration System and Other Measures to Prevent Severe Progression of Fatty Liver Disease

Japan Research Institute (Head Office: Shinagawa-ku, Tokyo; President: Atsushi Uchikawa; hereinafter "JRI") announces the release of the "Report on Improving Diagnostic Testing and Treatment Access for MASLD/MASH Patients in Japan" (hereinafter "this Report"), formulated by the "Expert Panel on Improving Diagnostic Testing and Treatment Access for MASLD/MASH Patients in Japan" (Note 1) organized by JRI.
This Report focuses on realizing early diagnostic testing and improving treatment access for MASLD (Metabolic Dysfunction Associated Steatotic Liver Disease) and MASH (Metabolic Dysfunction Associated Steatohepatitis) (hereinafter "MASLD/MASH", Note 2), which are fatty liver diseases based on metabolic dysfunction. It summarizes the challenges to be solved and specific policy recommendations.
This Report can be viewed from the following links:

"Report on Improving Diagnostic Testing and Treatment Access for MASLD/MASH Patients in Japan"
https://www.jri.co.jp/MediaLibrary/file/pdf/company/release/2026/0424.pdf
"Report on Improving Diagnostic Testing and Treatment Access for MASLD/MASH Patients in Japan" (Summary Version)
https://www.jri.co.jp/MediaLibrary/file/pdf/company/release/2026/0424_summary.pdf

■ Background and Overview of This Report
MASLD/MASH develops when fat accumulates in liver cells due to causes such as obesity, diabetes, and dyslipidemia. In recent years, MASLD/MASH has been rapidly increasing both domestically and internationally. JRI estimates that approximately 32 million adults in Japan, or about one in four, are affected. This disease can progress to liver cirrhosis and liver cancer in the future. JRI estimates that MASLD/MASH accounts for up to one in five (4.9-19.1%) of new liver cancer cases (Note 3). Furthermore, it has become clear that MASLD/MASH is not limited to liver disease but can also cause cardiovascular diseases (myocardial infarction, stroke, etc.). According to research by Ehime University, the proportion of patients with cardiovascular disease caused by MASLD/MASH is 17.0% of patients with cardiovascular disease, which is on par with hypertension and diabetes (cited from large-scale epidemiological surveys in Japan).
MASLD/MASH is expected to have a significant impact not only on public health but also on medical expenses. JRI estimates that if MASLD/MASH progresses to severe liver cirrhosis or liver cancer, medical expenses will swell by about 2.5 times compared to treating only MASLD/MASH. Thus, from the perspective of extending the healthy life expectancy of the public and optimizing medical expenses, promoting liver disease countermeasures against MASLD/MASH is important and is an area where future countermeasure promotion is expected.
In this Report, aiming to improve diagnostic testing and treatment access for MASLD/MASH patients, we collaborated with experts to understand the current situation, organize the desired future state and challenges to be solved, and compiled six countermeasures.

■ Challenges in the Medical Collaboration System for MASLD/MASH in Japan
Despite MASLD/MASH being a dangerous disease that affects many citizens and can cause liver and cardiovascular diseases, the diagnosis rate is low, reported at 12% (Note 4). This is thought to be due to MASLD/MASH progressing unnoticed without symptoms, and a lack of understanding among various stakeholders, including the public and medical professionals, regarding the dangers of MASLD/MASH. As a result, the number of patients whose condition worsens without receiving treatment is increasing.
Furthermore, measures such as screening systems through health check-ups, referral criteria to specialists, and securing treatment access are not necessarily sufficiently developed. Therefore, it is often the case that MASLD/MASH patients are not appropriately referred along the series of steps from health check-up → family doctor → specialized medical institution.
From the perspective of extending the healthy life expectancy of the public and optimizing medical expenses, it is an urgent task to promote countermeasures to conduct early testing and diagnosis, improve treatment access, and prevent the severe progression of MASLD/MASH.

■ Countermeasures to be Implemented
Countermeasure ① Disease awareness activities for citizens and patients
MASLD/MASH tends to progress without subjective symptoms, and many patients neglect it even if abnormalities are pointed out in health check-ups. Awareness activities to improve recognition of the disease itself and its dangers, and to encourage early consultation for MASLD/MASH,