Received: 26 March 2019
Accepted: 20 August 2019
First Online: 28 August 2019
Ethics approval and consent to participate
: The study was approved by the institutional review board of the Yonsei University Health System Clinical Trial Center. The informed consent was waived because this study was a retrospective study with review of related data through the electronic medical record. The datasets used and/or analyzed during the current study available from the corresponding author on reasonable request.
: Not applicable.
: The authors declare that they have no competing interests.