1. Department of Internal Medicine IV [Gastroenterology, Hepatology, and Infectious Diseases], Jena University Hospital, Jena, Germany
2. Klinik für Gastroenterologie, Pulmonologie und Allgemeine Innere Medizin, Evangelisches Krankenhaus Köln Kalk, University of Cologne, Cologne, Germany
3. Ambulanzzentrum Gastroenterologie, University Teaching Hospital Lüneburg, Lüneburg, Germany
4. Internistische Gemeinschaftspraxis für Verdauungs- und Stoffwechselkrankheiten Leipzig und Schkeuditz, Leipzig, Germany
5. Medical Faculty, Friedrich-Schiller University, Jena, Germany
6. Department of Internal Medicine I [Gastroenterology], University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
7. Department of Medicine I [Gastroenterology, Infectious Diseases, Rheumatology], Charité-Universitätsmedizin Berlin, Berlin, Germany
8. Department of Internal Medicine 1, University Hospital Carl Gustav Carus, Dresden, Germany
9. Department of Surgery, University Medical Center Regensburg, Regensburg, Germany