1. Division of Gastroenterology and Hepatology, Maastricht University Medical Center, Maastricht, The Netherlands
2. Department of Methodology and Statistics, Maastricht University Medical Center, Maastricht, The Netherlands
3. Department of Internal Medicine and Gastroenterology, Atrium-Orbis Medical Center, Heerlen, The Netherlands
4. Department of Internal Medicine and Gastroenterology, Zuyderland Medical Center, Sittard, The Netherlands