Funding for this research was provided by:
Sichuan Province Science and Technology Support Program (2020JDKP0023)
The Science and Technology Project of the Health Planning Committee of Sichuan (19PJ242)
Received: 10 February 2020
Accepted: 18 May 2020
First Online: 24 May 2020
Ethics approval and consent to participate
: Not applicable.
: All the authors consent to publish the paper.
: The authors declare that they have no competing interests.