Text and Data Mining valid from 2019-04-01
Received: 9 January 2019
Accepted: 16 March 2019
First Online: 1 April 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: All patients provided written informed consent forms before participation in the study.
: The study protocol was approved by the Institutional Review Board at Peking Union Medical College in accordance with the latest version of the Declaration of Helsinki. This trial was registered with ClinicalTrials.gov (#NCT02838225).