Received: 16 June 2021
Accepted: 30 November 2021
First Online: 15 December 2021
: This study was approved by the Institutional Review Board of Kyushu University (Clinical Bioethics Committee of the Graduate School of Healthcare Sciences, Kyushu University). As we used anonymized claims insurance data, the requirement to obtain informed consent was waived in accordance with the Ethical Guidelines for Medical and Biological Research involving Human Subjects in Japan [ExternalRef removed].
: Not applicable.
: The authors declare that they have no competing interests.