1. Department of Gastroenterology; Akershus University Hospital; Lørenskog Norway
2. Institute of Clinical Medicine; University of Oslo; Oslo Norway
3. Health Services Research Unit; Akershus University Hospital; Lørenskog Norway
4. Division of Medicine, Department of Gastroenterology; Oslo University Hospital Ullevål; Oslo Norway
5. Department of Medicine II, Gastroenterology and Hepatology; Medical University of Innsbruck; Innsbruck Austria