By Deborah Borfitz

April 7, 2022 | Japan has a variety of databases available to researchers, but knowledge and experience is needed to understand the characteristics of each one and select wisely, according to two representatives of CMIC Group, the country’s largest contract research organization. The database options are tied to Japan’s publicly funded healthcare system that provides universal health insurance and the freedom to choose among medical institutions offering consistently high-quality, low-cost medical care.

Three types of organizations hold medical information from electronic medical records, insurance databases, and the Japan Health Insurance Association, says Shuta Mitomo, CMIC Group director, who spoke first on navigating this real-world data (RWD) landscape at the recent Summit for Clinical Ops Executives (SCOPE). One is a national database provided by the Ministry of Health, Labour and Welfare (MHLW) for public interest purposes, and another the medical information database network (designated MID-NET) representing 8.3 million people from 20 large hospitals that was established by the MHLW and Pharmaceuticals and Medical Devices Agency to provide RWD for drug safety assessments.

The third group comprises private companies with data services created via collaboration with medical institutions and the government, Mitomo says. These include the NTT DATA, Medical Data Vision, and DeSC Healthcare (focused on disease management).

Data characteristics of administrative databases are different than that of insurance databases, he continues. A patient classification method knows as DPC (Diagnosis Procedure Combination) creates data on admissions to acute care hospitals. Data is generated once a month for each patient, and 90% of it is submitted electronically.

The overall healthcare system in Japan is comprehensive, Mitomo says. But it is mandatory to “use the right database for the right purpose.” 

Data scientist Yohei Hayashi, a CMIC Group specialist, says DeSC Healthcare—a joint venture between DeNA Co.  and Sumitomo Corporation—does research cooperatively with CMIC.  DeCS Healthcare holds three types of data from Japan’s three insurance schemes: residence-based National Health Insurance (NHI), employer-based health insurance, and health insurance for the elderly.

Both employer-based health insurance data and NHI data have a wide age distribution up to 74 years old, Hayashi says, but there are “major differences between the two.” The former skews relatively young while the latter represents many people 60 years and older. The age distribution on health insurance for the elderly is mostly people 75 years and older with an assortment of comorbidities.

One CMIC Group-DeSC Healthcare joint research project looking at death after an initial diagnosis of stroke exemplify some of the differences in medical database characteristics, Hayashi says. The incident rate of stroke was found to be a low 1.4% in the employer-based health insurance group, 2.2% in the NHI group, and a comparatively large 20.3% among those in the health insurance for the elderly database.