Article History
Received: 11 September 2019
Accepted: 14 January 2020
First Online: 22 January 2020
Ethics approval and consent to participate
: All subjects gave their verbal informed consent prior to their inclusion in the study. Written consent to participate was waived as the present study was a retrospective study using deidentified data, and patients will spend additional time and transportation costs for obtaining written consent to participate after discharge, which will increase the burden on patients. This study was approved by the Research Ethics Committee of the Xiangya Hospital, and was conducted according to the principles expressed in the Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.