Funding for this research was provided by:
Natural Science Foundation of Fujian Province (2017J01171)
the Startup Fund for scientific research, Fujian Medical University (2016QH113)
Received: 17 December 2018
Accepted: 15 May 2019
First Online: 3 June 2019
Ethics approval and consent to participate
: The study protocol was approved by the ethics committee of Fujian Provincial Hospital (Fujian, China) in accordance with 1964 Helsinki declaration. Consent was not required due to the retrospective nature of the study.
: Not applicable.
: The authors declare that they have no competing interests.
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