In 2014, the Ministry of Health, Labor and Welfare (MHLW) in Japan began to assume a cost-effectiveness perspective. Some expensive pharmaceutical and medical devices have been regulated, which resulted in a drastic change of the healthcare system.

The Japanese National Insurance Claims Database (NDB) is an administrative database based on claims data from Medical Insurance Claims since 2008. The government enacted the Act on Assurance of Medical Care for Elderly People during health care reform in 2008. In 2006, the MHLW commenced discussions on a framework for the optimization of the healthcare expenses, which aimed to evaluate the structure of the increase in healthcare expenditure.

The NDB was developed as a tool for investigation and analysis by the MHLW in the context of the Healthcare reform. In addition, the NDB was used for the development of academic research in order to contribute to the implementation and evaluation of healthcare policy management.

A major strength of the NDB is its exhaustiveness or completeness of insurance claims. The NDB collects data from all insured people nationwide and covers all medical institutions in Japan.

We applied to the Expert Meeting on Provision of Medical Insurance Claims to examine the research plan, items extracted, and data management. Inpatient and Outpatient information was extracted on medical procedures and payment. Diagnoses for both inpatients and outpatients are coded according to the International Classification of Diseases Tenth Edition (ICD-10). The coding of treatments and surgeries follow Japan's local procedure and surgical coding, which was specifically developed for insurance claims.

We generated any personally traceable patient ID from the “hash ID” generated by patient name, sex, date of birth, and insurer number with the aim of protecting personal identifying information in the NDB. The disease of stroke was defined to analyze the database for cost-effectiveness analysis, and to connect disease information to. The prescription claims information described pharmaceutical names, prescription date, total dose, and number of days.

Our study showed the new standard way of analysis for cost-effectiveness analysis using the Japanese National Insurance Claims Database.