Received: 28 June 2019
Accepted: 11 November 2019
First Online: 19 November 2019
Ethics approval and consent to participate
: This retrospective study was conducted according to the Ethical Guidelines for Medical and Health Research Involving Human Subjects. The present study was approved by the Ethics Review Committee of National Hospital Organization Ureshino Medical Center (approval number 18–17). No additional permissions were required to review the patient records, including the hospitals from which the records were obtained.
: Not applicable.
: The authors declare that they have no competing interests.