Funding for this research was provided by:
scientific research projects of Beijing Ditan Hospital, Capital Medical University (DTZZLX-202019)
Beijing Municipal Science and Technology Commission (D171100003117005)
Digestive Medical Coordinated Development Center of Beijing Hospitals Authority (XXZ04)
Received: 6 April 2020
Accepted: 13 May 2020
First Online: 7 June 2020
Ethics approval and consent to participate
: This study has been approved by the Ethics Committee of Beijing Ditan Hospital Capital Medical University (number: 2020–010-01).
: Not applicable.
: The authors declare that they have no competing interests.