Ueno, Tatsuya http://orcid.org/0000-0002-6212-0265
Kon, Tomoya
Haga, Rie
Nishijima, Haruo
Arai, Akira
Tomiyama, Masahiko
Article History
Received: 2 February 2020
Accepted: 10 April 2020
First Online: 23 April 2020
Compliance with ethical standards
:
: The authors declare that they have no conflicts of interest.
: The study protocol was approved by the institutional review board of the Aomori Prefectural Central Hospital. Since this study was a retrospective observational study, written informed consent was not obtained from the patients, and requirement for informed consent was waived by the institutional review board. However, we gave patients an opportunity to opt out of the study.