1. Radboud University Medical Center Nijmegen; Department of Gastroenterology and Hepatology; Geert Grooteplein Zuid 10 Nijmegen Netherlands 6525 GA
2. Copenhagen Trial Unit, Centre for Clinical Intervention Research, Department 7812, Rigshospitalet, Copenhagen University Hospital; The Cochrane Hepato-Biliary Group; Blegdamsvej 9 Copenhagen Denmark DK-2100