Text and Data Mining valid from 2019-03-07
Received: 1 August 2018
Accepted: 22 February 2019
First Online: 7 March 2019
Compliance with ethical standards
: Tiago Guedes, Marta Azevedo, João Morais, Carolina Andresen, Gustavo Coelho, Horácio Zenha, and Horácio Costa declare that they have no conflict of interest.
: Informed consent was obtained from all individual participants included in the study.
: 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 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this kind of retrospective study, formal consent is not required.