Received: 30 January 2021
Accepted: 20 April 2021
First Online: 27 April 2021
: This study was approved by the institutional review board (Chairman: Sueyoshi Moritani) of the Kusatsu General Hospital for this study (approval number: 2019–015). The need for informed consent was waived by the institutional review board because of the retrospective nature of the study. The data of participants, which used in this study, were anonymized before its use.
: Not applicable.
: The authors declare that they have no competing interests.