Text and Data Mining valid from 2019-06-27
Received: 26 December 2018
Accepted: 19 June 2019
First Online: 27 June 2019
Ethics approval and consent to participate
: The protocol for this study was approved by the institutional review board of Ewha Womans University Mokdong Hospital in Korea (IRB FILE No: EUMC 2018–10-032). All methods were performed in accordance with the relevant guidelines and regulations. Informed consent was waived by the institutional review board because of the study’s retrospective nature.
: Not applicable.
: The authors declare that they have no competing interests.