Press Release

Released: Thursday 17th September, 2015

The Lancet Diabetes & Endocrinology: Study suggests that patients with type 2 diabetes should be prioritised for obesity surgery​​

New research published in The Lancet Diabetes & Endocrinology suggests that, when considering overall costs of healthcare, obese patients with type 2 diabetes, especially those with recent disease onset, should be prioritised for obesity surgery over those without type 2 diabetes, since many patients see a reversal of diabetes after surgery and thus need fewer expensive diabetes medications or treatment for complications in future.

The research is based on the Swedish Obese Subjects (SOS) study from Sahlgrenska Academy, Gothenburg, Sweden, and performed in collaboration with Dr Martin Neovius, Karolinska Institutet, Stockholm, Sweden, Dr Lena Carlsson, Chief SOS Investigator, University of Gothenburg, Sweden, and Dr Catherine Keating, Deakin University and Baker IDI Heart and Diabetes Institute, Melbourne, Australia.

Currently most healthcare systems prioritise access to obesity surgery based on a person's body-mass index (BMI), and in general, those with the highest BMI are prioritised. Patients with lower BMIs and comorbidities such as type 2 diabetes can also be considered eligible for surgery, but different countries have different guidelines. Several groups have recommended that a person's diabetes status (rather than BMI alone), be used to prioritise obese patients to receive bariatric surgery. But so far, the long-term effect of bariatric surgery (relative to conventional therapy) on healthcare costs in obese patients according to their diabetes status has not been assessed using real-world data.

The SOS study was conducted in the Swedish healthcare system and including 2010 adults who underwent obesity surgery and 2037 matched controls recruited between 1987 and 2001. The data showed that accumulated drug costs over 15 years did not differ between the surgery and control group in patients without diabetes at the time of surgery, but were lower in surgery patients who had prediabetes (on average, -US$3329 per patient) or diabetes (-$5487 per patient). However, hospital costs were higher in all patients who had surgery.  No differences in outpatient costs were observed.

Compared with patients treated conventionally, total healthcare costs (accounting for costs of surgery, inpatient and outpatient hospital care and prescription drugs) were higher in surgery patients who did not have diabetes at the beginning of the study (by $22,390 per patient) or who had prediabetes ($26,292), but not in patients with diabetes, most likely because the remission of diabetes that often occurs after bariatric surgery means that patients need fewer diabetes medications and hospital appointments in the subsequent years. Remission of diabetes also means that diabetes complications are lessened, further reducing future healthcare costs.

"To our knowledge, this is the first prospectively controlled study to assess long-term healthcare costs in obesity surgery patients according to their preoperative diabetes status versus matched controls," say the authors.[1]

Because previous studies have assessed the entire eligible obese population, they have likely underestimated the cost benefits of obesity surgery for those with type 2 diabetes, while overestimating them for patients without type 2 diabetes. They conclude: "we show that for obese patients with type 2 diabetes, the upfront costs of bariatric surgery seem to be largely offset by prevention of future health-care and drug use. This finding of cost neutrality is seldom noted for health-care interventions, nor is it a requirement of funding in most settings. Usually, buying of health benefits at an acceptable cost (eg, £20 000 per quality-adjusted lifeyear in the UK) is the economic benchmark adopted by payers when new interventions are assessed. Bariatric surgery should be held to the same economic standards as other medical interventions."

Writing in a linked Comment, Dr Ricardo Cohen, Director of the Center of Excellence for Metabolic and Bariatric Surgery, Hospital Oswaldo Cruz, São Paulo, Brazil, says: "BMI should…not be the only indication for bariatric surgery. Thus, individuals that do not have their diabetes under control with the best pharmacological approach and lifestyle interventions should be prioritised for bariatric surgery, irrespective of their BMI."


This study was funded by AFA Försäkring and Swedish Scientific Research Council.

[1] Quote direct from author and cannot be found in text of Article.

Article: Dr Martin Neovius, Karolinska Institutet, Stockholm, Sweden.

Article: Dr Lena Carlsson, Principal Investigator for the SOS study, University of Gothenburg, Gothenburg, Sweden.

Article: Dr Catherine Keating, Deakin University and Baker IDI Heart and Diabetes Institute, Melbourne, Australia.

​Comment: Dr Ricardo Cohen,  Director of the Center of Excellence for Metabolic and Bariatric Surgery, Hospital Oswaldo Cruz, São Paulo, Brazil. ​

For full Article and Comment see:

For Appendix see:


Released: Friday 4th September, 2015

Surgery achieves better long-term control of type 2 diabetes than standard medical therapy

​Metabolic or bariatric surgery may be more effective than standard medical treatments for the long-term control of type 2 diabetes in obese patients, according to a new study by King's College London and the Universita Cattolica in Rome, Italy. The study, published in The Lancet, is the first to provide data on five-year outcomes of surgery from a randomized clinical trial specifically designed to compare this new approach against standard medical therapy for the treatment of type 2 diabetes. 

A number of studies have shown that bariatric or weight-loss surgery can result in dramatic improvement of type-2 diabetes in obese patients, supporting the idea that surgery could be used to treat this disease. Randomised controlled trials have shown that metabolic surgery is more effective than conventional treatment for the short-term control of type-2 diabetes. However, no trials have yet provided information on longer-term outcomes. 

The new study followed a group of diabetic patients from Italy aged 30-60 with a body-mass index (BMI) of 35 kg/m² or more who were randomly assigned to receive either conventional medical treatment for type-2 diabetes (20 patients) or surgery by gastric bypass (20) or biliopancreatic diversion (20).  Gastric bypass involves shrinking the size of the stomach and rerouting the upper part of the small intestine, whilst biliopancreatic diversion involves a more extensive bypassing of the intestine. 

Of the 60 patients enrolled on the trial, 53 completed the five-year follow-up which looked at the durability of diabetes remission, defined as achievement of a glycated haemaglobin A1c (HbA1c) concentration of 6.5% or less without the need for drugs for at least one year. Additional outcome measures included relapse of hyperglycaemia (high blood sugar); use of anti-diabetic medication (glucose-lowering drugs and insulin) and cardiovascular medication (blood pressure and lipid-lowering drugs); changes in body weight, BMI and waist circumference; blood pressure; cholesterol; cardiovascular risk; quality of life, diabetes-related complications and long-term surgical complications. 

Overall, 19 (50%) of the 38 surgical patients maintained diabetes remission at five years, compared with none of the 15 medically treated patients. Regardless of remission, surgical patients had generally lower levels of blood glucose than medically treated ones. Throughout the study period, surgical patients also used significantly less anti-diabetic and cardiovascular medication. The estimated cardiovascular risk at Year 5 for surgical patients was roughly half that of patients receiving conventional treatment. Surgery was also associated with better quality-of-life scores. 

There was no mortality and no major long-term complications after surgery. Biliopancreatic diversion resulted in greater remission rates of diabetes compared to gastric bypass at Year 5 (67% vs 37%); however, gastric bypass was associated with fewer significant nutritional side effects and better quality of life scores, suggesting that gastric bypass may have a better risk-to-benefit profile in patients with diabetes. 

Half of the patients who had initial diabetes remission experienced relapse of mild hyperglycaemia five year after surgery. For this reason, the authors caution that monitoring of glycaemia should continue in all patients who experience disease remission after bariatric surgery. 

However, the patients who experienced relapse of hyperglycemia maintained a mean HbA1c of 6.7% (indicating adequate control of diabetes) with just diet and either metformin or no medication, whereas before surgery the same patients had HbA1c greater than 7.0% (indicating inadequate control) despite taking multiple glucose-lowering drugs and/or insulin. Overall, more than 80% of surgically-treated patients maintained the American Diabetes Association's treatment goal of a glycated haemoglobin A1c concentration below 7.0%, with little or no need for anti-diabetic drugs. 

'The ability of surgery to greatly reduce the need for insulin and other drugs suggests that surgical therapy is a cost-effective approach to treating type-2 diabetes', says Professor Francesco Rubino, senior author of this study and Chair of Bariatric and Metabolic Surgery at King's College London and a Consultant Surgeon at King's College Hospital in London, UK. 

Fewer diabetes-related complications were also observed in surgical patients in this study; however, the authors caution that the limitations of this trial, especially its relatively small sample size, do not allow definitive conclusions about the ability of surgery to reduce diabetes complications (e.g. heart attacks, strokes, kidney disease).

Professor Geltrude Mingrone, first author of the study who is a Professor of Internal Medicine at the Universita Cattolica in Rome and a Professor of Diabetes and Nutrition at King's College London, says: 'The lower incidence of typical diabetes complications in this study is in line with previous findings from long-term non-randomized studies; however, larger and ideally multicentre randomized trials are needed to definitively confirm that surgery can reduce diabetes morbidity and mortality compared to standard medical treatment. Nevertheless, surgery appears to dramatically reduce risk factors of cardiovascular disease.'

​Surgical patients in this study lost more weight than medically treated patients; however, weight changes did not predict remission of hyperglycemia or relapse after surgery, suggesting that mechanisms other than weight loss are implicated in the effects of surgery on diabetes. 

Professor Rubino's earlier experimental studies in rodents provided initial evidence that modifications of gastric and intestinal anatomy can exert direct effects on the regulation of glucose metabolism.  He says: 'The results of this study add to a growing body of evidence showing that the gastrointestinal tract is a rational biological target for antidiabetic interventions and support implementation of surgery as a standard option in the treatment of type 2 diabetes.' 

The 3rd World Congress on Interventional Therapies for Type 2 Diabetes and 2nd Diabetes Surgery Summit will be held in London, UK on 28-30 of September 2015. The Congress and Summit are hosted by King's College London and are organized in partnership with world-leading diabetes organizations. For more information, please visit


Notes to editors 

For more information, please contact Jenny Gimpel, PR Manager (Health) in the King's College London press office on tel: +44 (0)20 7848 4334, email

'Bariatric surgery versus conventional medical treatment in obese patients with type 2 diabetes: 5-year follow-up of an open-label, single-centre, randomised controlled trial' by Mingrone et al is published in The Lancet on Friday 4 September 2015. 

The study was funded by the Universita Cattolica in Rome, Italy.


About King's College London 

King's College London is one of the top 20 universities in the world (2014/15 QS World University Rankings) and among the oldest in England. King's has more than 26,500 students (of whom nearly 10,400 are graduate students) from some 150 countries worldwide, and nearly 6,900 staff. The university is in the second phase of a £1 billion redevelopment programme which is transforming its estate.

​​For more information, please visit King's in Brief (

About Universita Cattolica and Policlinico Gemelli

The Gemelli Hospital of Universita Cattolica was founded in 1964 by Father Agostino Gemelli. It is one of the most important and internationally renowned care providers in Italy. Gemelli University Hospital has been ensuring excellence in both diagnostics and therapy for fifty years: as an academic medical center operating in all areas of health and clinical assistance, it is at the heart of the Italian healthcare system. It provides state-of-the-art personalized care to about 95,000 inpatients and 250,000 outpatients per year; about 200 medical doctors and 270 PhDs graduate each year from the institution.

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