Funding for this research was provided by:
program of Key Research and Development Plan in Anhui in 2017 (1704a0802149)
Text and Data Mining valid from 2018-12-01
Received: 2 February 2018
Accepted: 30 November 2018
First Online: 13 December 2018
Ethics approval and consent to participate
: The ethics committee of Anhui Provincial Hospital ruled that no formal ethics approval was required in this retrospective study. Patients in this study are made aware that their de-identified data may be used for research purposes, and they can opt out if they object to the use of their data.
: Not applicable.
: The authors declare that they have no competing interests.
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