Text and Data Mining valid from 2019-04-16
Received: 10 January 2019
Accepted: 12 April 2019
First Online: 16 April 2019
Compliance with ethical standards
: The author(s) declare that they have no competing interests.
: The ethics committee of our institution approved the study protocol (number TEIRIN 17-111). The study protocols were developed in accordance with the ethical guidelines of the Declaration of Helsinki. This observational trial was registered with the University Hospital Medical Information Network (number UMIN R000036168).
: The need for informed consent was waived because of the retrospective study design.