Funding for this research was provided by:
Japanese Ministry of Health, Labor and Welfare
Text and Data Mining valid from 2018-12-01
Received: 11 May 2018
Accepted: 26 November 2018
First Online: 19 December 2018
Ethics approval and consent to participate
: The protocol and consent procedures were approved by the institutional review board of each participating hospital.
: Not applicable.
: The authors declare that they have no competing interests.
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