Yan, Ting
Li, Shuang‐Ling
Ou, Hai‐Li
Zhu, Sai‐Nan
Huang, Lei
Wang, Dong‐Xin http://orcid.org/0000-0002-3205-1836
Article History
First Online: 21 January 2020
Compliance with ethical standards
:
: The authors declare that they have no conflict of interests.
: Because of the retrospective and observational nature of the study, the local Ethics Committee agreed to exempt written informed consent.
: The original study protocol was approved by the Clinical Research Ethics Committee of Peking University First Hospital (2017–1303).