Funding for this research was provided by:
Ministry of Science and Technology of the People's Republic of China (2020YFC084370067)
Received: 4 April 2020
Revised: 30 April 2020
Accepted: 20 May 2020
First Online: 10 June 2020
Compliance with ethical standards
: The scientific guarantor of this publication is Shenghong Ju.
: The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.
: No complex statistical methods were necessary for this paper.
: Written informed consent was waived by the Institutional Review Board.
: Institutional Review Board approval was obtained.
: • retrospective• observational• multicenter study
Free to read: This content has been made available to all.