Funding for this research was provided by:
Digestive Medical Coordinated Development Center of Beijing Hospitals Authority (XXT06)
Text and Data Mining valid from 2020-03-18
Received: 8 November 2019
Accepted: 2 March 2020
First Online: 18 March 2020
Ethics approval and consent to participate
: Not applicable.
: The authors declare that they have no competing interests.