Funding for this research was provided by:
scientific research grants from the Ministry of Education, Culture, Sports, Science and Technology of Japan (15H05006, 16K09034)
the Ministry of Health, Labor, and Welfare of Japan (25112601)
Text and Data Mining valid from 2019-11-19
Received: 28 May 2019
Accepted: 9 November 2019
First Online: 19 November 2019
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.