Funding for this research was provided by:
Ministry of Education, Culture, Sports, Science and Technology (17H04141)
the Ministry of Health, Labour and Welfare, Japan (H30-Policy-Designated-004 and H29-ICTGeneral-004)
Text and Data Mining valid from 2019-08-27
Received: 18 May 2019
Accepted: 16 August 2019
First Online: 27 August 2019
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of The University of Tokyo Hospital. The requirement for obtaining informed consent from patients was waived because the data sets were anonymous.
: Informed consent was waived because of the anonymous nature of the data.
: The authors declare that they have no competing interests.