Received: 23 January 2020
Accepted: 29 May 2020
First Online: 10 June 2020
Ethics approval and consent to participate
: This study protocol was approved by the Nagoya University Hospital Institutional Review Board (2019–0089). Because this was a retrospective observational study and the data analyzed were anonymized, informed consent from participants or their parents/guardians was obtained through an opt-out method on our hospital website in accordance with the Ethical Guidelines for Medical and Health Research Involving Human Subjects in Japan.
: Informed consent for publication was obtained in the form of opt-out.
: The authors declare that they have no competing interests.