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.