Funding for this research was provided by:
National Natural Science Foundation of China (81502301)
Text and Data Mining valid from 2019-04-23
Received: 25 October 2018
Accepted: 5 April 2019
First Online: 23 April 2019
Ethics approval and consent to participate
: This study involved the use of existing collections of data or records that contain only non-identifiable data. Thus, ethics approval is not needed. Written, informed consent was provided by all participants in each of the studies included in this individual patient meta-analysis.
: Not applicable.
: The authors declare that they have no competing interests.
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