Zhang, Luwen
Jing, Dian
Lu, Qiaochu
Shen, Shuqun
Article History
Received: 16 November 2020
Accepted: 26 February 2021
First Online: 15 March 2021
Declarations
:
: The protocol of study and accessing the hospital admission data was approved by the ethics committee of School of Public Health of Southern Medical University, and was performed by the ethical standards noted in the 1964 Declaration of Helsinki and its later amendments.
: The authors declare that they have no competing interests.