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Bypass surgery beats lifestyle modification for T2DM and obesity

The surgical cohort also lowered their haemoglobin A1c levels by an average of 1.79% compared to 0.39% for the lifestyle management cohort

Gastric bypass surgery can give better control for diabetes and obesity than lifestyle modification, according to the results from a randomised clinical trial comparing two treatments. Whilst both groups of participants report significant weight loss, better diabetes management and improved quality of life, scientists from Joslin Diabetes Center and Brigham and Women's Hospital found that bypass patients did significantly better, after three years, than patients provided with an intensive diabetes and weight management programme.

"Our study demonstrates that in patients with mild-moderate obesity and type 2 diabetes, gastric bypass surgery leads to a sustained reduction in weight, improvement in glycaemic control, and decrease in cardiovascular risk compared to a medical diabetes and weight management programme," said lead author, Dr Donald C Simonson of the BWH Division of Endocrinology, Diabetes and Hypertension. "Gastric bypass surgery and the medical/lifestyle intervention programme are not investigational - both are routinely available to patients at our institutions, and comparable programmes exist at many other hospitals and health care facilities."

The research paper, ‘Clinical and Patient-Centered Outcomes in Obese Type 2 Diabetes Patients 3 Years After Randomization to Roux-en-Y Gastric Bypass Surgery Versus Intensive Lifestyle Management: The SLIMM-T2D Study’, published in Diabetes Care,

The trial randomly allocated 38 obese patients (23 females) with type 2 diabetes to treatment either by surgery or through Joslin's Why WAIT intensive lifestyle management programme. Joslin's 12-week Why WAIT intensive lifestyle management programme includes a change in diabetes medications to enhance weight reduction, structured dietary intervention with lower carbohydrates and higher protein and meal replacement, an exercise programme with emphasis on strength training, and weekly educational and support sessions.

Participants had an average weight of 230lbs and BMI36.3. Changes in weight, HbA1c, cardiovascular risk factors (UKPDS risk engine), and self-reported health status (the 36-Item Short-Form [SF-36] survey, Impact of Weight on Quality of Life [IWQOL] instrument, and Problem Areas in Diabetes [PAID] questionnaire) were assessed.


After three years, patients given surgery saw dramatically greater weight loss, averaging 55lbs compared to 11lbs for those in the lifestyle management intervention. The surgical cohort also lowered their haemoglobin A1c levels (a measure of blood sugar over several months) by an average of 1.79% compared to 0.39% for the lifestyle management cohort.

Additionally, those given surgery showed significantly lower risk of coronary heart disease and stroke. Changes in cardiometabolic risk for coronary heart disease and stroke were all more favourable in RYGB versus lifestyle management intervention (p<0.05 to p<0.01). IWQOL improved more after RYGB (p<0.001), primarily due to subscales of physical function, self-esteem, and work performance. SF-36 and PAID scores improved in both groups, with no difference between treatments. A structural equation model demonstrated that improvement in overall quality of life was more strongly associated with weight loss than with improved HbA1c and was manifest by greater improvements in IWQOL than with either SF-36 or PAID.

Although patients given the lifestyle intervention programme made encouraging initial progress in both weight loss and diabetes control, those improvements dropped noticeably over time.

"Patients who had the gastric bypass procedure had superior ability to sustain changes both in weight and blood sugar, and they did so requiring less medication for their diabetes, their blood pressure and their lipids," added Dr Allison Goldfine, head of clinical research at Joslin during the trial and senior author of the paper.

Goldfine emphasised that treatment must be personalised for all patients who are struggling with obesity and diabetes, and that gastric bypass surgery is not always the best option.

"Older surgical procedures were much more invasive, with much higher surgical risk and complication rates, and older types of procedures had higher failure rates over time," she added. "Laparoscopic rather than open surgery made the biggest impact on the surgical experience and recovery, but we have improved surgical techniques all the way from preoperative evaluations to better post-operative care."

Medical options also have improved substantially, with the availability in recent years of new classes of diabetes drugs such as GLP-1 (glucagon-like peptide-1) receptor agonists and SGLT2 (sodium-glucose co-transporter-2) inhibitors. These drugs lower blood sugars, reduce weight and have lower rates of hypoglycaemia.

"As a result of these findings, we expect that more physicians will consider gastric bypass surgery as a viable option for patients with type 2 diabetes and mild to moderate obesity when previous attempts to lose weight and improve glycaemic control have not been successful," said Simonson.

Another arm of the SLIMM-T2D trial is examining the use of an adjustable band procedure. In previously released SLIMM-T2D research, participants given gastric band surgery or intensive lifestyle management achieved similar lowering of blood sugar levels after one year. Participants given the band saw greater average weight loss (30 pounds compared to 19 pounds).

The research team at Joslin and BWH is now joining in a larger study known as ARMMS-T2D (Alliance of Randomized Trials of Medicine versus Metabolic Surgery in Type 2 Diabetes). ARMMS-T2D will follow about 240 patients from four smaller-scale randomized controlled trials (including SLIMM-T2D) that compared bariatric surgical procedures with lifestyle interventions. The Joslin/Brigham site for the ARMMS-T2D study is led by Joslin principal investigator, Dr Mary-Elizabeth Patti.

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