Funding for this research was provided by:
the Ministry of Education, Science, Culture and Sports of Japan (17390239 and 2139053)
Received: 26 February 2021
Accepted: 20 April 2021
First Online: 12 May 2021
: This study was approved by the ethics committees of KKR Sapporo Medical Center, Sapporo City General Hospital, Hokkaido Social Insurance Hospital (current JCHO Hokkaido Hospital), Sapporo Social Insurance General Hospital (current JCHO Hokushin Hospital), Iwamizawa City General Hospital, Iwamizawa Rosai Hospital (current Hokkaido Chuo Rosai Hospital), Otaru City Hospital, Otaru Kyokai Hospital, Kinikyo Chuo Hospital, and Tenshi Hospital. This study was conducted in accordance with the Declaration of Helsinki and approved by the ethics committee of Hokkaido University School of Medicine (med02-001). All participants provided written informed consent. All participants, including deceased participants, agreed with our consecutive analysis using their clinical data even if they died.
: Not applicable.
: MS, HM, KS, SK, and MN have received grants from Boehringer-Ingelheim and Pfizer during the conduct of the study. MS has received grants from Boehringer-Ingelheim, Novartis, and AstraZeneca outside the submitted work. MN has received personal fees from Boehringer-Ingelheim, Novartis, and AstraZeneca outside the submitted work. YA and HK declare that they have no conflicts of interest in this work.