Weight loss surgery can be effective for long term treatment of type 2 diabetes

by Barbara Hewitt on September 8, 2015

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.

The research is the first to provide data on five year outcomes of surgery from a randomised clinical trial specifically designed to compare this new approach against standard medical therapy for the treatment of type 2 diabetes.

bypass surgery diabetesA 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 by King’s College London and the Universita Cattolica in Rome, Italy, followed a group of diabetic patients from Italy aged 30 to 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, or surgery by gastric bypass or biliopancreatic diversion.

Some 20 were allocated to each group and the study explained that gastric by pass involved shrinking the size of the stomach and re-routing the upper part of the small intestine, whilst biliopancreatic diversion involved 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 haemoglobin A1c (HbA1c) concentration of 6.5% or less without the need for drugs for at least one year.

Additional outcome measures included relapse of high blood sugar levels, use of anti-diabetic medication such as glucose lowering drugs and insulin and cardiovascular medication such as blood pressure and lipid-lowering drugs as well as 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, 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 five for surgical patients was roughly half that of patients receiving conventional treatment. Surgery was also associated with better quality of life scores.

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 hyperglycaemia 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%, indicating inadequate control, despite taking multiple glucose lowering drugs and/or insulin.

“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”, said 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.

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 such as heart attacks, strokes, and kidney disease.

“The lower incidence of typical diabetes complications in this study is in line with previous findings from long-term non-randomized studies,” said 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. “However, larger and ideally multi centre randomised 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 hyperglycaemia or relapse after surgery, suggesting that mechanisms other than weight loss are implicated in the effects of surgery on diabetes.”


The opinions expressed in this article do not necessarily reflect the views of the DiabetesForum.com Community and should not be interpreted as medical advice. Please see your doctor before making any changes to your diabetes management plan.

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