1 Division of Gastroenterology and Endocrinology, University Medical Center Rostock, Rostock, Germany.
2 Medical Clinic 1, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.
3 Department of General, Visceral- and Vascular Surgery, Charité - University Medicine Berlin, Campus Benjamin Franklin, Berlin, Germany.
4 Medical Department (Gastroenterology, Infectious Diseases, Rheumatology), Charité - University Medicine Berlin, Campus Benjamin Franklin, Berlin, Germany.
5 Department of Internal Medicine IV (Gastroenterology, Hepatology, and Infectious Diseases), Jena University Hospital, Jena, Germany.