Funding for this research was provided by:
Sichuan Province Science and Technology Support Program (2018SZ0246, 2020YFS0153)
Received: 14 October 2020
Accepted: 29 November 2020
First Online: 7 December 2020
Ethics approval and consent to participate
: Before the study began, we had carefully consulted the Ethics Committee and Institutional Review Board of West China Hospital. They suggested that this study did not involve special interventions for patients, and we should conduct this study in compliance with the Helsinki Declaration and inform patients fully of the purpose of the study. So, all data was fully anonymised at source with researchers. Given the anonymous nature of the data, the ethics committee waived any requirement for patient informed consent.
: Not applicable.
: The authors declare that they have no competing interests.