Received: 12 March 2018
Accepted: 21 December 2018
First Online: 28 January 2019
Ethics approval and consent to participate
: The study protocol was approved by the Ethics Committee of the “12 de Octubre” University Hospital and by the Research Committee of the Universidad Europea de Madrid. All participants gave their written informed consent.
: Not applicable
: The authors declare that they have no competing interests.
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