Published on in Vol 20, No 6 (2018): June
Preprints (earlier versions) of this paper are
available at
https://preprints.jmir.org/preprint/9070, first published
.

1 Department of Community Medicine, Information and Health Decision Sciences, Faculty of Medicine, University of Porto, Porto , PT
2 Serpa Pinto Family Health Unit , Agrupamento de Centros de Saúde Porto Ocidental, Porto , PT
3 Chronic Diseases Research Centre, NOVA Medical School, NOVA University of Lisbon, Lisboa , PT
4 Centre for Health Technology and Services Research , University of Porto, Porto , PT