1 Endoscopy Research Unit, Ulm University Hospital, Ulm, Baden-Württemberg, Germany anna.fichtl@uniklinik-ulm.de.
2 Department of Internal Medicine I, Ulm University Hospital, Ulm, Baden-Württemberg, Germany.
3 Endoscopy Research Unit, Ulm University Hospital, Ulm, Baden-Württemberg, Germany.
4 Medical Clinic III - Clinic for Gastroenterology, Metabolic Disorders, and Internal Intensive Medicine, University Hospital Aachen, Aachen, Nordrhein-Westfalen, Germany.
5 Department of General, Visceral and Transplantation Surgery, Interdisciplinary Endoscopy Unit, University Hospitals Tubingen, Tübingen, Baden-Württemberg, Germany.
6 Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Baden-Württemberg, Germany.