Received: 13 February 2019
Accepted: 8 August 2019
First Online: 14 August 2019
Ethics approval and consent to participate
: The study protocol was approved by the Institutional Review Board of the Chonnam National University Hospital and was performed in accordance with the ethical standards of the 1964 Declaration of Helsinki. All participants provided their written informed consent to participate in this study.
: Not applicable.
: The authors declare that they have no competing interests.