When diet and exercise don’t work, people who are obese sometimes turn to a more radical approach: weight-loss surgery to remove or bypass parts of the stomach or small intestine. Bariatric surgery (also called metabolic surgery) has helped many people lose significant amounts of weight and keep it off.
Over the years, as the procedure became more widely used, doctors discovered an added benefit. Patients with type 2 diabetes, a condition commonly associated with excess weight, had their diabetes improve or go into remission (when blood sugar returns to normal without the help of medications) after the procedure.
Experts believe surgery may affect glucose metabolism or cause changes in the gut, which improves insulin action, triggering complete or partial diabetes remission. In fact, the most common obesity operation, gastric bypass, can lead to diabetes resolution soon after surgery, even before patients began to lose weight. Because of these surgical effects, bariatric surgery is often called metabolic surgery when it’s used to treat diabetes.
Will the effects last?
An important question among experts has been whether protection against diabetes would persist. So far, studies have borne out long-lasting-and safe-glycemic control. A recent clinical trial, published in February in The New England Journal of Medicine, builds on that body of evidence. The STAMPEDE (Surgical Treatment and Medications Potentially Eradicate Diabetes Efficiently) trial, led by Cleveland Clinic researchers, followed 134 patients with uncontrolled type 2 diabetes and body mass indexes (BMI) of 27 to 43. A BMI of 25 to 29 is considered overweight; 30 and above is considered obese. Participant ages ranged from 20 to 60.
Participants were randomly selected to undergo intensive diabetes drug therapy alone or drug therapy with metabolic surgery. In the surgery group, half underwent a procedure known as Roux-en-Y gastric bypass and the other half underwent sleeve gastrectomy (see below).
Five years later, the surgery patients were doing significantly better than those in the medication-only group as evidenced by many measures, including weight, insulin use, and quality of life, such as improved pain levels and emotional well-being. They also had better glycemic control and were using fewer, if any, diabetes medications.
Nearly half of those who underwent surgery-29 percent of the gastric bypass group and 23 percent of the sleeve gastrectomy group-lowered their hemoglobin A1c levels (a marker of diabetes control) to 6 percent or less. Readings above 6.5 percent indicate diabetes. Only 5 percent of patients taking medication alone lowered their A1c to 6 percent or below.
Is metabolic surgery for you?
The STAMPEDE trial was relatively small and involved patients no older than 60; older adults may experience different results. According to the American Diabetes Association (ADA), younger age, a diabetes duration of less than eight years, nonuse of insulin, and better glycemic control are associated with higher remission rates. The ADA doesn’t place an age limit on surgical candidates, however.
The ADA’s 2017 diabetes guidelines state that metabolic surgery should be:
- Recommended for people with type 2 diabetes and a BMI of 40 or higher regardless of how well they’re currently managing their blood sugar levels.
- Recommended for people with a BMI between 35 and 39, and Asian-Americans with a BMI between 32 and 37, who can’t control diabetes through lifestyle and medication.
- Considered for people with a BMI who haven’t been able to control their blood sugar levels with medication or lifestyle.
Medicare and many insurance policies cover metabolic surgery for people with a BMI of 35 or higher, but with certain restrictions. It’s important to find a surgical center that performs these procedures frequently and has a multidisciplinary team with experience both in gastrointestinal surgery and in managing diabetes. The more experience surgeons have performing metabolic surgery, the higher the success rate and the fewer complications.
Undergoing metabolic surgery is a serious decision. Like all forms of surgery, it carries the risk of complications, such as bleeding and infection. Because digestive tract function is altered, many patients develop nutritional deficiencies. As a result, you must commit to long-term management. Overall, the death rate with metabolic surgery is between 0.1 and 0.5 percent, and the risk for complications is between 2 and 6 percent.
The benefits of surgery can exceed the risks for many people, especially those with poorly controlled diabetes. Ask your doctor about your benefits and risks.
These procedures are the most commonly performed metabolic surgeries:
- Roux-en-Y gastric bypass. A small stomach pouch is created by connecting part of the stomach to the small intestine, causing a faster sense of fullness and less calorie absorption.
- Sleeve gastrectomy. About 80 percent of the stomach is removed, leaving a small sleevelike stomach that limits food intake.
- Adjustable gastric banding. An adjustable band ties off the top of the stomach, creating a small pouch and restricting food intake. It’s less effective for losing weight and treating diabetes than other procedures.