Study data
We analysed the National Patients Sample (NPS) data from the Korean
Health Insurance Review and Assessment (HIRA) Service from 2018
(HIRA-NPS-2018-0078). HIRA is a repository of claims data collected for
reimbursement purposes.23 HIRA-NPS data, a nationally
representative sample of whole beneficiaries, were extracted with sex-
and age-stratified random sampling methods from all patients who used
medical services in 2018.24 The data comprise the
complete insurance claim data of 3% of the general
population.24
Diagnostic information for HIRA-NPS was coded according to the Korean
Standard Classification of Diseases version 7 (KCD-7), which is based on
the International Classification of Diseases 10th Revision (ICD-10).
HIRA-NPS data contain fields representing the individual patient
characteristics (age, sex, and type of insurance), medical institutions
(type of institution and region), and outpatient and inpatient clinical
management (medical procedures and medications).
The Institutional Review Board (IRB) of Pusan National University
approved this study (PNU IRB/2021_29_HR). This study used secondary
data obtained from the HIRA and contained no personal information;
therefore, written consent was waived by the IRB.