Chen, Chu
Funding for this research was provided by:
Ministry of Education of the People's Republic of China (18YJA790062, XN0305A)
National Natural Science Foundation of China (71870412)
Sichuan University (2018SCUH0027)
China Medical Board (17-276)
Article History
Received: 18 December 2018
Accepted: 16 May 2019
First Online: 31 May 2019
Ethics approval and consent to participate
: This study has been approved by the ethics committee of Sichuan University, China, and the approval number is K2018087. The data used in our analysis are administrative data. All the personal privacy information has been desensitized before analysis.
: Not applicable.
: The authors declare that they have no competing interests.