Cleveland Clinic Study: Use of Bariatric Surgery Beats Medical Therapy in Diabetes Management

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Bariatric surgery has more powerful long-term effects on controlling type 2 diabetes mellitus (T2DM) that medical therapy alone, according to the largest, long-term study comparing methods.

Bariatric surgery has more powerful long-term effects on controlling type 2 diabetes mellitus (T2DM) than medical therapy alone, according to the largest, long-term study comparing methods.1

Results of the Cleveland Clinic’s STAMPEDE study were shared at Monday’s late-breaking session of the 63rd Scientific Sessions of the American College of Cardiology, which concluded in Washington, DC. The results were simultaneously published in The New England Journal of Medicine,1 and the study’s presenter, Sangeeta Kashyap, MD, answered questions immediately afterward at a press briefing.

Dr Kashyap captured headlines in February 20132 when she published a substudy of STAMPEDE in Diabetes Care,3 the journal of the American Diabetes Association (ADA). In that article, Dr Kashyap outlined the mechanism by which bariatric surgery, which has been used primarily to help obese patients lose large amounts of weight, has helped patients overcome their T2DM status within days, long before they shed the pounds.

As she explained at the time, “A gastric bypass changes hormones in the gut, which triggers the pancreas to start making insulin again.”2


Researchers at the Cleveland Clinic designed STAMPEDE, which stands for Surgical Therapy And Medications Potentially Eradicate Diabetes Efficiently, to assemble evidence that might make surgery an acceptable alternative to medication in combating T2DM, which affects 25 million Americans; an estimated 79 million also have prediabetes, according to the ADA.4

Results presented Monday involved 150 patients, age 41 to 57 years, who received 1 of 3 treatment options: intensive medical therapy that included lifestyle changes and counseling along with medication; medical therapy plus Roux-en-Y gastric bypass; or medical therapy plus sleeve gastrectomy. Almost all of the patients, 91.3%, remained in the study at the 3-year mark.

At the start of the study, the average glycated hemoglobin (A1C) level for all patients was 9.2%. Most patients had been living with the disease at least 8 years and were taking at least 3 antidiabetic medications. All were overweight, although some patients had a body mass index as low as 27 kg/m2, which might not make them a candidate for bariatric surgery without T2DM. Women made up 66% of the study group.

All 3 groups saw a drop in A1C levels at the 6-month mark; however, the groups receiving surgery were largely able to sustain the declines over 3 years, while the group receiving only medical therapy experienced a gradual rise to levels approaching preintervention rates. Results were:

  • The medical-only group began with an average A1C of 9.0%, followed by an average of 7.1% at 6 months; 7.5% at 12 months; 7.7% at 24 months; and 8.4% at 36 months.
  • The gastric bypass (Roux-en-Y) group began with an average A1C of 9.3%, followed by averages of 6.3% at 6 months; 6.5% at 12 months; 6.5% at 24 months; and 6.7% at 36 months.
  • The sleeve group began with an average of 9.5%, followed by averages of 6.7% at 6 months; 6.6% at 12 months; 6.8% at 24 months; and 7.0% at 36 months.

At the 3-year mark, weight loss was 5 to 6 times greater for patients who received gastric bypass or sleeve surgery compared with those receiving medical therapy only. Average loss for the gastric bypass group was 24%; average loss for the sleeve group was 21%; while average loss for the medical therapy only group was just 4%.5

Researchers acknowledge that these surgical procedures are not without risks, which they listed as bleeding, infection, or blood clots. The study team reported that the most common issues at 12 months were short-term dehydration, bleeding, and 1 leak. Four of the 100 surgical patients needed an additional surgery for complications within the first year.

One issue that was not reported came up in response to a question from The American Journal of Managed Care. Dr Kashyap was asked if investigators observed the phenomenon, reported in the literature since 2012, that some gastric bypass patients experience alcohol abuse in year 2 after surgery. This topic was explored in a recent issue of Evidence-Based Diabetes Management.5

Dr Kashyap said that “2 or 3” patients experienced alcohol abuse, but that it turned out that those patients had had some history of substance abuse issues. When asked why these incidents were not reported as adverse events, Dr Kashyap said it was due to the patients’ histories.

In her presentation, Dr Kashyap emphasized that surgical patients outscored the medical therapy group on quality-of-life tests; when asked about this at the late-breaking session, she said that the weight loss gave patients confidence, and that for patients who no longer had needed insulin injections, quality of life improved enormously.

The lead author on the study, Philip Schauer, MD, said endocrinologists were interested in the phenomenon, but without long-term results, most were unwilling to consider surgery as a therapy alongside traditional pharmacological-based therapies and lifestyle modifications. “Now the evidence is mounting, and we see the benefits of surgery over medical therapy for these patients,” he said in a statement.6


  1. Schauer PR, Bhatt DL, Kirwan JP, et al. Bariatric surgery vs. intensive medical therapy for diabetes. N Engl J Med. Published online March 31, 2014.
  2. Theiss E. Cleveland Clinic shows why gastric bypass can trounce diabetes. The Plain Dealer. Published February 26, 2013. Accessed March 31, 2014.
  3. Kashyap SR, Bhatt DL, Wolski K, et al. Metabolic effects of bariatric surgery in patients with moderate obesity and type 2 diabetes: analysis of a randomized control trial comparing surgery with intensive medical treatment. Diabetes Care. 2013;36(8):2175-2182.
  4. Fast facts. American Diabetes Association website. Updated March 2013. Accessed March 30, 2014.
  5. Mehr S. The link between a common type of bariatric surgery and increased alcohol use. Am J Manag Care. 2014;20(SP4)SP116-SP118.
  6. Bariatric surgery beats medical therapy alone for managing diabetes [press release]. Washington, DC: American College of Cardiology; March 31, 2014.