Data analysis of the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) Open Data Japan with an adjustment of confounding factors

National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) Open Data Japan publishes summary tables of fundamental data from NDB. In this report, we performed a pilot study on the mental health and dental care of patients with noncommunicable diseases (NCDs) using NDB Open Data Japan. We performed data analysis using the Sex- and Age-Standardized Regional Difference Index (SA-RDI) to preliminarily show the relationship between diabetes mellitus and periodontal disease. Consequently, we could visualize the relationship between them at the prefectural (community) level.