Received: 19 November 2020
Accepted: 1 March 2021
First Online: 9 March 2021
: This study was conducted in accordance with the Ethical Guidelines for Medical and Health Research Involving Human Subjects. The Kitasato University Kitasato Institute Hospital, Research Ethics Committee, approved the study (Control number: 18061). For this retrospective study, we disclosed the purpose of the study to participants and provided the option of opt-out before participating in the study. All participants provided written informed consent to participate in this study. In addition, opt-out notices, rather than informed consent, provided an opportunity to refuse research participation.
: Not applicable.
: The authors declare that they have no competing interests.