Received: 14 April 2019
Accepted: 6 August 2019
First Online: 16 August 2019
Ethics approval and consent to participate
: We conducted a retrospective observational study and used the “opt-out” method as a way to obtain informed content from patients. The study was approved by the Human Experimentation Committee of our institution (no. 20120279).
: We have obtained the consent for publication from all patients.
: Yuko Kitagawa received a designated donation from Kyowa Hakko Kirin Co., Ltd., Otuska Pharmaceutical Co., Ltd. and Yakult Honsha Co., Ltd. His institution has an endowed chair from Yakult Honsha Co., Ltd. The other authors declare that they have no competing interests.