Received: 6 April 2020
Accepted: 7 July 2020
First Online: 20 July 2020
Ethics approval and consent to participate
: This retrospective study was performed in accordance with the guidelines of the Declaration of Helsinki. This study was approved by the Institutional Review Board of Kyorin University School of Medicine (IRB No. 1353) on September 5, 2019. Informed consent was obtained using an opt-out method with a written notice. Administrative permission was not required to access and use the medical records described in this study.
: Not applicable.
: The authors declare that they have no competing interests.