Funding for this research was provided by:
National Health Insurance Service
Received: 18 May 2017
Accepted: 18 January 2018
First Online: 25 January 2018
Ethics approval and consent to participate
: This study was approved by the Internal Review Board (IRB) of the National Health Insurance Service Ilsan Hospital, and informed written consent was obtained from all patients. (NHIMC-2016-09-001).
: Not applicable
: The authors declare that they have no financial or other conflicts of interest in relation to this research and its publication.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.