Funding for this research was provided by:
Ministry of Science ICT and Future Planning (2016M3A9E8941329)
Text and Data Mining valid from 2019-02-04
Received: 20 September 2018
Accepted: 27 January 2019
First Online: 4 February 2019
Compliance with ethical standards
: This study was approved by the Institutional Review Board of Asan Medical Center and was conducted according to the Ethical Principles for Medical Research Involving Human Subjects as defined by the Helsinki Declaration.
: All participants in this study provided informed consent.