Funding for this research was provided by:
Scientific Research Foundation for Returned Scholars of Ministry of Education (1174)
Received: 16 November 2020
Accepted: 25 February 2021
First Online: 6 March 2021
: As this was an extended retrospective study of relevant approved prospective studies [2020ER(A) 068] and does not harm the interests of the patients, it was exempted by the Ethics Committee of North Sichuan Medical College.
: Not applicable for this study.
: The authors declare that they have no competing interests.