Text and Data Mining valid from 2019-04-02
Received: 7 October 2018
Accepted: 24 March 2019
First Online: 2 April 2019
Ethics approval and consent to participate
: This study protocol was approved by the institutional human ethics review board of Kumamoto University Hospital (approval number: 1448). Because this was a retrospective study and included no therapeutic intervention, the institutional human ethics review board of Kumamoto University Hospital and other three affiliated hospitals waived the need for written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.
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