Text and Data Mining valid from 2019-01-18
Received: 30 May 2018
Accepted: 28 November 2018
First Online: 18 January 2019
Ethics approval and consent to participate
: All procedures performed in studies involving human participants were in accordance the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The institutional research committee of the Fifth Affiliated Hospital of Guangzhou Medical University approved the study. Written informed consent was obtained from every participant.
: Consent to publish to report individual patient data was obtained from every participant.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.