1. Public Health Institute of Porto, 4050-600 Porto, Portugal
2. Intensive Care Medicine Service at Centro Hospitalar Universitário São João (CHUSJ), 4200-319 Porto, Portugal
3. Medicine Department at Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal
4. Internal Medicine Service at Centro Hospitalar Universitário São João (CHUSJ), 4200-319 Porto, Portugal
5. General Surgery Service at Centro Hospitalar Universitário São João (CHUSJ), 4200-319 Porto, Portugal
6. ISPUP-EPIUnit—Instituto de Saúde Pública da Universidade do Porto, 4050-600 Porto, Portugal