[1] Univ Cattolica Sacro Cuore, Digest Endoscopy Unit, Rome, Italy
[2] Univ Oslo, Dept Hlth Econ & Hlth Management, Oslo, Norway
[3] Oslo Univ Hosp, Dept Transplantat Med, Gastroenterol Unit, Oslo, Norway
[4] Maria Sklodowska Curie Mem Canc Ctr, Med Ctr Postgrad Educ, Dept Gastroenterol & Hepatol, Warsaw, Poland
[5] Inst Oncol, Warsaw, Poland
[6] Gen Infirm, Ctr Digest Dis, Leeds LS1 3EX, W Yorkshire, England
[7] Univ London Imperial Coll Sci Technol & Med, St Marks Hosp, Wolfson Unit Endoscopy, London SW7 2AZ, England
[8] Avicenne Hosp, Dept Gastroenterol, Paris, France
[9] Univ Amsterdam, Acad Med Ctr, Dept Gastroenterol & Hepatol, NL-1105 AZ Amsterdam, Netherlands
[10] L Curto Hosp, Div Gastroenterol, Polla, Sant Arsenio, Italy
[11] New Mowasat Hosp, Gastroenterol Unit, Salmiya, Kuwait
[12] Nuovo Regina Margherita Hosp, Digest Endoscopy Unit, Rome, Italy
[13] Univ Hosp Geneva, Serv Gastroenterol & Hepatol, Geneva, Switzerland