Text and Data Mining valid from 2019-04-10
Received: 5 November 2018
Accepted: 1 April 2019
First Online: 10 April 2019
Compliance with Ethical Standards
: The authors declare that they have no conflict of interest.
: For this type of study, formal consent is not required. The study protocol was approved by the Catholic University of Korea St. Vincent’s Hospital Institutional Review Board (IRB approval number: VC18RESI0177).