1. Department of Gastrointestinal Surgery, Hospital Clínic de Barcelona, Barcelona, Spain;
2. Department of Gastroenterology, Hospital Universitario de Canarias, Santa Cruz de Tenerife, Spain;
3. Endoscopy Unit, Department of Digestive Diseases, Hospital Universitari Doctor Josep Trueta, Girona, Spain;
4. Department of Gastroenterology, Hospital Quirón Madrid, Madrid, Spain;
5. Department of Gastroenterology, Hospital General Universitario Gregorio Marañon, Madrid, Spain;
6. Department of General and Digestive Surgery, Hospital Universitario Infanta Sofía, San Sebastián de los Reyes, Spain;
7. Department of Gastroenterology, Hospital Universitario de Cabueñes, Asturias, Spain;
8. Department of Gastroenterology, Hospital de Sabadell, Institut d´Investigació i Innovació Parc Taulí I3PT, CIBERehd, Sabadell, Spain;
9. Department of Gastroenterology, Hospital Universitario 12 de Octubre, Madrid, Spain;
10. Department of Gastroenterology and Hepatology, Hospital Universitario Marques de Valdecilla, Santander, Spain;
11. Department of Gastroenterology and Hepatology, IRYCIS, Hospital Universitario Ramón y Cajal, Universidad de Alcalá, Madrid, Spain;
12. Endoscopy Unit, Department of Digestive Diseases, Hospital Universitari de Bellvitge, Bellvitge Biomedical Research Institute (IDIBELL), University of Barcelona, Barcelona, Spain;
13. Endoscopy Unit, Department of Gastroenterology, Son Espases University Hospital, Illes Balears, Spain;
14. Department of Gastroenterology, University of Navarra Clinic, Madrid, Spain;
15. Department of Gastroenterology, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain;
16. Department of Gastroenterology, Hospital Virgen de la Salud, Toledo, Spain;
17. Endoscopy Unit, Department of Gastroenterology, Hospital Clínico San Carlos, Madrid, Spain;
18. Endoscopy Unit, Department of Digestive Diseases, Hospital Universitari Mútua de Terrassa, Terrassa, Spain;
19. Department of Gastroenterology, Hospital del Mar Medical Research Institute, Barcelona, Spain;
20. Endoscopy Unit, Department of Gastroenterology, Hospital Clinic de Barcelona, Barcelona, Spain;
21. Endoscopy Unit, Department of Gastroenterology, IDIBAPS, CIBERehd, Hospital Clinic de Barcelona, Barcelona, Spain;
22. Department of Clinical Farmacology, Hospital Clinic and Medical Statistics Core Facility, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain;
23. Biostatistics Unit, Faculty of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain;
24. Department of Gastrointestinal Surgery, ICMDM, IDIBAPS, CIBEREHD, AIS Channel, Hospital Clínic de Barcelona, Barcelona, Spain.