1. Department of General, Emergency and Metabolic Surgery, Rovigo Hospital, 45100 Rovigo, Italy
2. Department of Surgery, University of Turku, 20014 Turku, Finland
3. Department of Surgery and Transplantation, University Hospital Zurich, University of Zurich, 8006 Zurich, Switzerland
4. HM Delfos, 08023 Barcelona, Spain
5. Department of General Surgery, Holy Family Hospital, Nazareth 1601001, Israel
6. The Azrieli Faculty of Medicine, Bar-Ilan University, Ramat Gan 5290002, Israel
7. Department of Surgery, Bariatric Endoscopy, Medical Faculty Mannheim, Heidelberg University, 69167 Heidelberg, Germany
8. Department of Surgery, Cerrahpasa Medical Faculty, Istanbul University, 34320 Istanbul, Turkey
9. Bariatric and Metabolic Surgery Unit, Department of General and Laparoscopic Surgery, Ospedale Evangelico Betania, 80147 Naples, Italy
10. Department of Medical Surgical Sciences and Translational Medicine, Sant’Andrea Hospital, Sapienza University, 00189 Rome, Italy
11. Department of Surgical Sciences, University of Tor Vergata, 00133 Rome, Italy
12. Department of Surgery and Gastroenterology, Catharina Hospital, 5623 Eindhoven, The Netherlands
13. Endocrine-Metabolic and Bariatric Surgery Unit, Vall Hebron Barcelona Hospital Campus, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain
14. Department of Surgery, Faculty of Medicine and Health, Örebro University, 70182 Örebro, Sweden
15. Center for Obesity Northern-Netherlands (CON), Department of Bariatric and Metabolic Surgery, Medical Center, 8934 Leeuwarden, The Netherlands
16. Division of Visceral Surgery, Department of General Surgery, Medical University of Vienna, 1090 Vienna, Austria
17. Delta CHIREC Hospital (Belgian Registry), 1160 Brussels, Belgium
18. Digestive Surgery and Liver Transplantation Unit, Université Côte d’Azur, 06103 Nice, France
19. Department of Surgery, Whittington Hospital, University College, London N19 5NF, UK
20. Department of Surgery, Ponderas Academic Hospital, 014142 Bucharest, Romania
21. OB Klinika—Center for Treatment of Obesity and Metabolic Disorders, 1300 Prague, Czech Republic
22. General and Digestive Surgery Department, Fuenlabrada University Hospital, Rey Juan Carlos University, 28942 Madrid, Spain
23. The Center for Obesity and Diabetes, Hospital Alemao Oswaldo Cruz, Sao Paulo 01323-20, Brazil
24. San Marco Hospital GSD, 24046 Zingonia, Italy
25. Public Health Department, School of Medicine, University Federico II of Naples, 80138 Naples, Italy
26. Centro Multidisciplinar Do Tratamento da Obesidade, Hospital Lusíadas Amadora e Lisboa, 2724-002 Amadora, Portugal
27. Diabetic Foot Unit, University of Florence and AOU-Careggi, 50121 Florence, Italy