Data source
The National Health Insurance Service (NHIS) database is used in this
investigation. The NHIS provides insurance claims data for 50 million
subscribers in Korea, and this study was created using data from a
sample of 3.5 million persons from 2008 to 2019. This information
contained general medical history information (diagnosis code,
hospitalization date, treatment code, and death information) as well as
patient information (age, gender, residential area, economic status, and
death information). (NHIS-2021-1-689) We used The Strengthening the
Reporting of Observational Studies in Epidemiology (STROBE) Statement.