Funding for this research was provided by:
Ministry of Health, Labour and Welfare
Received: 5 February 2020
Accepted: 19 May 2020
First Online: 11 September 2020
Ethics approval and consent to participate
: This study was approved by the institutional review boards of St. Marianna University School of Medicine (approval number 2406) and was registered with the University Hospital Medical Information Network-Clinical Trials Registry (UMIN000018937). We used an anonymous physician questionnaire for the survey [CitationRef removed] and informed consent was not required in Japan at that time (2009), and even now [CitationRef removed].
: Not applicable (anonymous data).
: The authors declare that they have no competing interests.