1. Department of Internal Medicine I, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
2. Department of Health Services Research and General Practice, Faculty of Life Sciences, University of Siegen, Siegen, Germany
3. Department of General Practice and Family Medicine, Philipps-University, Marburg, Germany
4. Center for Digestive Diseases, Internal Medicine Center Eppendorf, Hamburg, Germany
5. Practice of Gastroenterology, Berlin, Germany
6. Asklepios Klinik St. Georg Haus L, IFI Institut für Interdisziplinäre Medizin, Hamburg, Germany
7. Department of Internal Medicine and Gastroenterology, Helios Klinikum Krefeld, Krefeld, Germany
8. Department of Internal Medicine, Diakonie Klinikum Jung-Stilling, Siegen, Germany