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Article History

Received: 6 September 2020

Accepted: 11 April 2021

First Online: 2 May 2021

Declarations

:

: This retrospective study was approved by the institutional review board/ethics committee (Ethics Committee, Kindai University Faculty of Medicine; the Ethics Review Board of Hyogo College of Medicine; Ethics Committee on Epidemiological Studies, Kagoshima University Graduate School of Medical and Dental Sciences; Tottori University Ethical Review Board; Institutional Review Board of the National Center for Global Health and Medicine; the Institutional Review Board of Hokkaido University Hospital for Clinical Research; and the Medical Ethics committee, Kurashiki Central Hospital), and the need for patient informed consent was waived.

: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Because our study is a retrospective study, formal consent is not required. This article does not contain any studies with animals performed by any of the authors.

: The authors declare no competing interests.