Saku Central Hospital: backup drive with medical claims data on 87,765 patients is missing

In June 2026, Nagano Prefectural Federation of Agricultural Cooperatives for Health and Welfare's Saku Central Hospital found that a portable hard drive kept by its insurance claims office was missing. It was used to back up medical data for insurance claims and went missing in a staff-only area closed to outsiders. Searches inside the hospital and checks with the Personal Information Protection Commission and the police have not found it, and the hospital cannot rule out that it was thrown away by mistake. It announced the case on 30 October. [1]

The drive holds medical data for insurance claims from 1 April 2019 to the end of February 2026 on 87,765 people: names, birth dates, sex, insurer numbers, diagnoses, tests, drugs, procedures and detailed symptom notes. Apart from names and symptom notes the data is coded and hard to read, the hospital says. Addresses, phone numbers, My Number, bank account and card data are not included. [1]

No leak or misuse has been found, and the hospital considers a leak very unlikely. [1]

It is sending individual notices to the people affected and opened a dedicated phone line. It is checking how storage media are managed and revising the steps for keeping and disposing of them. [1]