1. Department of Gastroenterology; German Diagnostic Clinic Helios Clinic Wiesbaden; Wiesbaden Germany
2. Department of Gastroenterology; Karlsruhe Hospital; Karlsruhe Germany
3. Departments of Biostatistics and Epidemiology; University Medical Center of the Johannes Gutenberg University Mainz; Mainz Germany
4. Department of Visceral, Transplant, Thoracic and Vascular Surgery; University Medical Center of Leipzig; Leipzig Germany