Text and Data Mining valid from 2019-01-10
Received: 15 June 2018
Accepted: 27 December 2018
First Online: 10 January 2019
Ethics approval and consent to participate
: The study protocol conforms to the ethical guidelines of the 1975 Declaration of Helsinki and was approved by the Clinical Research Ethics Committee of the First Affiliated Hospital of Sun Yat-sen University (2015–47). There was a waiver of consent in the present retrospective study as this project meets the criteria according to Health & Human Services regulations (45 CFR 46).
: Not Applicable.
: The authors declare that they have no competing interests.
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