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Article History

Received: 13 August 2019

Accepted: 6 December 2019

First Online: 18 December 2019

Ethics approval and consent to participate

: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the principles of the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. The present study was retrospective; for this type of study, the local ethics committee waived formal consent.

: Not applicable.

: The authors declare that they have no competing interests.