[1] Johannes Gutenberg Univ Mainz, Dept Med 1, D-55131 Mainz, Germany
[2] Johannes Gutenberg Univ Mainz, Dept Med Biometr Epidemiol & Informat, D-55131 Mainz, Germany
[3] Univ Hosp, Dept Med 2, Mannheim, Germany
[4] Univ Marburg, Univ Hosp, Dept Gastroenterol, Marburg, Germany
[5] Charite, Dept Gastroenterol, Berlin, Germany
[6] Univ Med Berlin Charite, Med Clin 1, Berlin, Germany
[7] Univ Hosp, Dept Gastroenterol, Essen, Germany
[8] Univ Hosp, Dept Gastroenterol, Regensburg, Germany
[9] Univ Hosp, Dept Gastroenterol, Munster, Germany
[10] Kalk Hosp, Dept Internal Med, Cologne, Germany
[11] Univ Hosp, Dept Gastroenterol, Ulm, Germany
[12] Univ Heidelberg Hosp, Dept Surg, Heidelberg, Germany
[13] Univ Hosp, Dept Gastroenterol, Jena, Germany
[14] Goethe Univ Frankfurt, Dept Gastroenterol, Frankfurt, Germany
[15] Univ Berlin, Virchow Hosp, Dept Gastroenterol, Berlin, Germany
[16] Univ Amsterdam, Acad Med Ctr, Dept Gastroenterol, NL-1105 AZ Amsterdam, Netherlands
[17] Univ Hosp, Dept Gastroenterol, Leuven, Belgium