1. Gastroenterology Department, University Hospital, Ferrol, Spain.
2. Gastroenterology Department, Puerta de Hierro University Hospital, Madrid, Spain.
3. Gastroenterology Department, Bellvitge University Hospital; IDIBELL Barcelona University, Barcelona, Spain.
4. Gastroenterology Department, Central University Hospital, Oviedo, Spain.
5. Gastroenterology Department, San Pedro de Alacantara University Hospital, Cáceres, Spain.
6. Gastroenterology Department, Poniente University Hospital, Almeria, Spain.
7. Gastroenterology Department, Dr. Negrín University Hospital, Las Palmas de Gran Canaria, Spain.
8. Gastroenterology Department, Marqués de Valdecilla University Hospital, Santander, Spain.
9. Gastroenterology Department, La Fe University Hospital, Valencia, Spain.
10. Gastroenterology Department, Miguel Servet University Hospital, Zaragoza, Spain.
11. Gastroenterology Department, Gregorio Marañón University Hospital, Madrid, Spain.
12. Gastroenterology Department, Instituto de Investigación Sanitaria Princesa and CIBERehd, La Princesa University Hospital, Madrid, Spain.
13. Gastroenterology Department, Ramón y Cajal University Hospital, Madrid, Spain.
14. Gastroenterology Department, Fuenlabrada University Hospital, Madrid, Spain.
15. Instituto Universitario de Ciencias de La Salud e INIBIC, La Coruña University, La Coruña, Spain.