Text and Data Mining valid from 2018-10-15
Received: 5 June 2018
Revised: 14 August 2018
Accepted: 14 September 2018
First Online: 15 October 2018
Compliance with ethical standards
: The scientific guarantor of this publication is Ye Wang at West China Hospital, Sichuan University.
: The authors declare that they have no competing interests.
: No complex statistical methods were necessary for this paper.
: Written informed consent was waived by the institutional review board, as this was a retrospective study.
: Institutional review board approval was obtained.
: • Retrospective• Observational study• Performed at one institution