Acknowledgments
The authors thank Mr. Hideyuki Kato, Dr. Hiroshi Kawano, Dr. Tatsuya Otsu, Dr. Masahide Hara, and Dr. Kazuya Goto (National Hospital Organization Nishi-beppu Hospital, Oita) for their advice and support.
Ethical approval
The study protocol was approved by the Institutional Ethics Committee of National Hospital Organization Nishi-Beppu Hospital, Oita, Japan (Approval Number: 1-7; Approval Date: 27 December 2019).
Disclosure statement
All of the authors have stated explicitly that there are no conflicts of interest in connection with this article.