1. Department of Digestive and Hepatobiliary Diseases, Estaing University Hospital, Clermont-Ferrand, France
2. Endoscopy Unit, Paoli Calmette Institute, Marseille, France
3. Biostatistics Unit, DRCI, Gabriel Montpied University Hospital, 63003 Clermont-Ferrand, France
4. Clinical Research Unit, Estaing University Hospital, Clermont-Ferrand, France