Received: 4 June 2019
Accepted: 31 July 2019
First Online: 9 August 2019
Ethics approval and consent to participate
: the study was approved by the hospital ethics committee of the reference center, Puerta de Hierro University Hospital. According to the normative in place, adherence to it was acknowledged by the Ethics committee of the remaining participating centres.
: All authors have read and approved the current submission.
: The authors declare that they have no competing interests.