Funding for this research was provided by:
Natural Science Foundation of Guangdong Province (2018030310559)
National Natural Science Foundation of China (81803327)
Received: 30 January 2022
Accepted: 31 January 2022
First Online: 19 February 2022
: The protocol of this study and the access to hospital admission data were approved by the Ethics Committee of the School of Public Health of Southern Medical University. It was performed in accordance with the ethical standards noted in the 1964 Declaration of Helsinki and its later amendments.
: Not Applicable.
: We declare that there is no conflict of interest.