Wang, Kai
Wang, Na
Wang, Yuliang
Xia, Yayi
Song, Feixue
Liu, Jingsheng
Article History
First Online: 6 December 2018
Compliance with ethical guidelines
:
: K. Wang, N. Wang, Y. Wang, Y. Xia, F. Song, and J. Liu declare that they have no competing interests.
: This article does not contain any studies with human participants or animals performed by any of the authors. Institutional review board approval and patient consent were not required for this meta-analysis of observational studies.