Text and Data Mining valid from 2020-01-04
Received: 25 October 2019
Accepted: 27 December 2019
First Online: 4 January 2020
Ethics approval and consent to participate
: This study was performed in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of Korea University Anam Hospital (No.2019AN0411).
: Not applicable.
: The authors declare that they have no competing interests.