Funding for this research was provided by:
National Natural Science Foundation of China (81671595)
Article History
Received: 28 October 2019
Accepted: 19 January 2020
First Online: 12 March 2020
Ethics approval and consent to participate
: The research protocol was approved by the ethics committee or review committee of the Hangzhou Aeronautical Sanatorium of Chinese Air Force. Because the study was a retrospective study based on real-world situations, there was no need to obtain informed consent from the patients.
: All authors agree to publish this work.
: The authors declare that they have no competing interests.