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Article History

Received: 8 October 2017

Accepted: 19 December 2018

First Online: 1 February 2019

Ethics approval and consent to participate

: Ethics approval and participant consent was not necessary as this study involved the use of a previously-published de-identified database according to the decree law n. 196 of 30 June 2003.

: Unidentifiable participants.

: The authors declare that they have no competing interests.

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