Xu, Yanyan
Xu, Qiaoyu
Sun, Hongliang
Liu, Tongxi
Shi, Kaining
Wang, Wu
Funding for this research was provided by:
the National Natural Science Foundation of China (81501469)
the Health Industry Special Scientific Research Project of National Health and Family Planning Commission of the People’s Republic of China (201402019)
Article History
Received: 5 December 2017
Revised: 8 January 2018
Accepted: 12 January 2018
First Online: 15 February 2018
Compliance with ethical standards
:
: The scientific guarantor of this publication is Dr. Hongliang Sun.
: 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.
: One of the authors has significant statistical expertise.No complex statistical methods were necessary for this paper.
: Written informed consent was waived in this study.
: Institutional Review Board approval was obtained.
: • retrospective• observational• performed at one institution