Received: 5 April 2020
Accepted: 1 October 2020
First Online: 27 October 2020
Ethics approval and consent to participate
: Data used in this work were obtained under the project with acronym EuroFlow which was approved by the ethics comity <i>Comité de Ética Asistencial del Área de Salud de Salamanca (Hospital Universitario de Salamanca, Salamanca (Spain))</i> in an ordinary session on February the 26th of 2007. The participants granted written permission for their data to be used for research purposes.
: Not applicable
: The authors declare that they have no competing interests.