Received: 4 November 2020
Accepted: 29 April 2021
First Online: 11 May 2021
: The study protocol was reviewed and approved by the Ethics Committee of Chinese Clinical Trial Registry (ChiECRCT-20180166). Informed consent was waived as there was no personal identifiable information in the database. As this study was based entirely on the analysis of routinely collected hospital administrative data, no experiment was conducted. All methods used in this study were in accordance with relevant guidelines and regulations.
: Not applicable.
: The authors declare that they have no competing interests.