1. Hospital Universitario de La Princesa- IIS-IP- Universidad Autónoma de Madrid and CIBEREHD, Gastroenterology Unit, Madrid, Spain
2. Complexo Hospitalario Universitario de Santiago, Gastroenterology Unit, Santiago de Compostela, Spain
3. Hospital Universitario Reina Sofía and IMIBIC, Gastroenterology Unit, Córdoba, Spain
4. Hospital de Galdakao-Usansolo, Gastroenterology Unit, Vizcaya, Spain
5. Hospital Universitario de Gran Canaria Dr. Negrin, Gastroenterology Unit, Las Palmas, Spain
6. Hospital Universitari Mutua Terrasa and CIBERehd, Gastroenterology Unit, Tarrasa, Spain
7. Hospital San Pedro, Gastroenterology Unit, Logroño, Spain
8. Hospital Universitari Son Espases, Gastroenterology Unit, Palma de Mallorca, Spain
9. Hospital Clínico Universitario ‘Lozano Blesa’- IIS Aragón and CIBEREHD, Gastroenterology Unit, Zaragoza, Spain
10. Hospital General Universitario de Ciudad Real, Gastroenterology Unit, Ciudad Real, Spain
11. Hospital Universitari i Politecnic La Fe and CIBEREHD, Gastroenterology Unit, Valencia, Spain
12. Hospital Universitario Central de Asturias and ISPA, Gastroenterology Unit, Oviedo, Spain
13. Hospital Universitario Marqués de Valdecilla, Gastroenterology Unit, Santander, Spain
14. Hospital Universitario San Pedro de Alcántara, Gastroenterology Unit, Cáceres, Spain
15. Complejo Hospitalario De Navarra, Gastroenterology Unit, Pamplona, Spain
16. Hospital Universitario de Burgos, Gastroenterology Unit, Burgos, Spain
17. Hospital General Universitario J.M. Morales Meseguer, Gastroenterology Unit, Murcia, Spain
18. Universidad Autónoma de Madrid/IdiPaz and CIBERESP, Preventive Medicine and Public Health, Madrid, Spain