Exploring Designated Intractable Diseases: Patient Numbers and Medical Expense Subsidization Rates Through DPC Data

February 29th, which occurs only in leap years, is recognized as “Rare Day,” and the final day of February each year marks Rare Disease Day (RDD)—a global awareness day for rare and intractable diseases. This year, RDD falls on Friday, February 28th.

RDD, initiated in Europe in 2008, is the world’s largest social awareness event, now recognized in over 100 countries. It aims to promote research and development, improve access to healthcare, and enhance patient support.

Designated intractable diseases refer to conditions characterized by unknown causes, a lack of established treatments, rarity, and a need for long-term care. These are diseases designated by Japan’s Minister of Health, Labour, and Welfare. As of April 2024, 341 diseases are recognized, and certified patients are eligible for medical expense subsidies. Notably, since April 2016, DPC data reporting mandates the inclusion of disease notification numbers and information on medical expense subsidization for designated intractable diseases.

Using the “Designated Intractable Diseases and Clinical Research Patient Lists” from the Ministry of Health, Labour, and Welfare, and analyzing MDV’s DPC data from April 2016 onwards, rankings of hospitalized patients with designated intractable diseases (top 10 conditions) were compiled. Additionally, MDV Analyzer was used to create data summaries for the following:

1. Total estimated patient numbers, including outpatients (Table 1).
2. Diseases with a medical expense subsidization rate exceeding 90% (Table 2).
3. Diseases with low medical expense subsidization rates (Table 3).

We welcome inquiries about the application of the MDV database in research on designated intractable and rare diseases.

Data Period for MDV Analyzer: April 2016 – October 2024.

Diseases with fewer than 10 actual patients were excluded.

Diseases with fewer than 10 actual patients were excluded.

For reference (Japanese only):

• Ministry of Health, Labour, and Welfare, “Designated Intractable Diseases and Clinical Research Patient Lists” (https://www.mhlw.go.jp/stf/newpage_36011.html).
• 2024 DPC Evaluation and Verification Survey (Discharged Patient Survey) Implementation Explanation Materials P31, P83: (https://www01.prrism.com/dpc/2024/file/setumei_20240531.pdf)

Column (Japanese only):

• What are Rare and Designated Intractable Diseases?

Note: This article was published on February 1, 2025.