Metabolic Surgery in the Treatment Algorithm for Type 2 Diabetes: A Joint Statement by International Diabetes Organizations
Authors: Rubino Francesco , Nathan David M. , Eckel Robert H. , Schauer Philip R. , Alberti K. George M.M. , Zimmet Paul Z. , Del Prato Stefano , Ji Linong , Sadikot Shaukat M. , Herman William H. , Amiel Stephanie A. , Kaplan Lee M. , Taroncher-Oldenburg Gaspar , Cummings David E. ,   Delegates of the 2nd Diabetes Surgery Summit, Albache Nizar , Batterham Rachel L. , Bhatt Deepak L. , Boza Camilo , Cefalu William T. , Cohen Ricardo V. , Courcoulas Anita P. , Dinneen Sean F. , Dixon John B. , Ferrannini Ele , Fioretto Paola , Frühbeck Gema , Gagner Michel , Grant Richard W. , Ikramuddin Sayeed , Johnston Desmond G. , Kashyap Sangeeta R. , Kelly Tracy , Klupa Tomasz , Korner Judith , Laferrère Blandine , Lebovitz Harold E. , Lee Wei-Jei , le Roux Carel W. , Mechanick Jeffrey I. , Mingrone Geltrude , Morton John M. , Pories Walter J. , Ratner Robert E. , Rayman Gerry , Sugerman Harvey J. , Van Gaal Luc , Vidal Josep , Weng Jianping , Wolfe Bruce M. 
Published: May 2016

BACKGROUND
Despite growing evidence that bariatric/metabolic surgery powerfully improves type 2 diabetes (T2D), existing diabetes treatment algorithms do not include surgical options.

AIM
The 2nd Diabetes Surgery Summit (DSS-II), an international consensus conference, was convened in collaboration with leading diabetes organizations to develop global guidelines to inform clinicians and policymakers about benefits and limitations of metabolic surgery for T2D.

METHODS
A multidisciplinary group of 48 international clinicians/scholars (75% nonsurgeons), including representatives of leading diabetes organizations, participated in DSS-II. After evidence appraisal (MEDLINE [1 January 2005–30 September 2015]), three rounds of Delphi-like questionnaires were used to measure consensus for 32 data-based conclusions. These drafts were presented at the combined DSS-II and 3rd World Congress on Interventional Therapies for Type 2 Diabetes (London, U.K., 28–30 September 2015), where they were open to public comment by other professionals and amended face-to-face by the Expert Committee.

RESULTS
Given its role in metabolic regulation, the gastrointestinal tract constitutes a meaningful target to manage T2D. Numerous randomized clinical trials, albeit mostly short/midterm, demonstrate that metabolic surgery achieves excellent glycemic control and reduces cardiovascular risk factors. On the basis of such evidence, metabolic surgery should be recommended to treat T2D in patients with class III obesity (BMI ≥40 kg/m2) and in those with class II obesity (BMI 35.0–39.9 kg/m2) when hyperglycemia is inadequately controlled by lifestyle and optimal medical therapy. Surgery should also be considered for patients with T2D and BMI 30.0–34.9 kg/m2 if hyperglycemia is inadequately controlled despite optimal treatment with either oral or injectable medications. These BMI thresholds should be reduced by 2.5 kg/m2 for Asian patients.

CONCLUSIONS
Although additional studies are needed to further demonstrate long-term benefits, there is sufficient clinical and mechanistic evidence to support inclusion of metabolic surgery among antidiabetes interventions for people with T2D and obesity. To date, the DSS-II guidelines have been formally endorsed by 45 worldwide medical and scientific societies. Health care regulators should introduce appropriate reimbursement policies.