Text and Data Mining valid from 2018-04-04
Received: 22 November 2017
Accepted: 25 March 2018
First Online: 4 April 2018
Ethics approval and consent to participate
: The study was approved by the Institutional Ethics Committee of West China Hospital of Sichuan University and complied with Declaration of Helsinki. Written informed consent was obtained from all subjects.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.