Nam, Bora http://orcid.org/0000-0003-0215-3855
Kim, Hyoungyoung http://orcid.org/0000-0003-1415-461X
Jang, Eun Jin http://orcid.org/0000-0002-9137-9815
Cho, Soo-Kyung http://orcid.org/0000-0003-4493-8837
Sung, Yoon-Kyoung http://orcid.org/0000-0001-6691-8939
Kim, Tae-Hwan http://orcid.org/0000-0002-3542-2276
Article History
Received: 16 June 2019
Accepted: 29 July 2019
First Online: 2 August 2019
Compliance with ethical standards
: To protect patient privacy, the National Health Insurance (NHI) stores beneficiary identifications in an encrypted format and provides data to the public without individual identifiers. Using these data allowed our study to be included in exemption categories (Institutional Review Board file no. HYUH 2018-12-027).
: The authors have declared no conflicts of interest.