1. A.S. Loginov Moscow Clinical Scientific Center, Department of Pancreatic, Biliary and Upper Digestive Tract Disorders, 111123 Moscow, Russia
2. Department of Propaedeutic of Internal Diseases and Gastroenterology, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, 127473 Moscow, Russia
3. Department of Outpatient Therapy and Family Medicine, Tver State Medical University, 170100 Tver, Russia
4. Department of Faculty Therapy and Gastroenterology, Omsk Sate Medical University, 644099 Omsk, Russia
5. Department of Pathological Anatomy, Omsk Sate Medical University, 644099 Omsk, Russia
6. Digestive Diseases Service, Aragón Health Research Institute (IIS Aragón), University Clinic Hospital, University of Zaragoza, 50009 Zaragoza, Spain