Weight loss surgery can make a big difference for people with obesity and Type 2 diabetes.
Evidence shows that weight loss surgery can slow down or even stop the progression of Type 2 diabetes. For some people blood sugar levels get back to normal within days to weeks after surgery. This means they need less medication or none at all.
There is general agreement that gastric sleeve and gastric bypass surgery should be offered as an option for people with Type 2 diabetes and obesity (with body mass index above 35).
In my experience, after gastric bypass surgery I can typically halve my patient’s dose of insulin and/or tablets by the time they leave the hospital, three days later.
What do studies show?
The data has been overwhelmingly positive.
One long-term study tracked 400 people with Type 2 diabetes for six years after they had weight loss surgery. More than 60 out of every 100 people in the study had their diabetes put into remission by the surgery. This means their symptoms disappeared completely and they no longer required medication. They also had better blood pressure, cholesterol and triglyceride levels.
Other studies have tracked people who took medicine and made lifestyle changes, such as improved diet and increased physical activity. Typically only 6 to 8 people out of every 100 achieved a similar improvement in their Type 2 diabetes.
Which operation is the best?
In terms of diabetes management, not all weight loss surgery is equally effective.
A recent analysis of 26 studies involving almost 8000 patients showed that gastric bypass surgery was the more effective for diabetes than gastric sleeve surgery. Out of every 100 people who had gastric bypass surgery, 75 had their diabetes put into remission. Only 60 people out of every hundred achieved the same result after a sleeve gastrectomy.
An additional benefit is that people who can take less diabetes medication also achieve better weight loss. This is because medication to control diabetes causes weight gain, so reducing the dose improves weight loss following weight loss surgery.
Gastric bypass surgery usually refers to the Roux-en-Y gastric bypass, which is considered worldwide as the gold standard for gastric bypass surgery. Another from that is gaining in popularity is known as the Omega-Loop or Mini Gastric bypass. Recent short to medium term studies suggest that it may be a more effective treatment for Type 2 diabetes than the Roux-en-Y gastric bypass, with remission rates of up to around 88%. Long-term data is being awaited.
When is surgery indicated to treat diabetes?
Those who have Type 2 diabetes and a body mass index (BMI) above 35 may want to consider bariatric surgery. This is almost a third of our Type 2 diabetics in Australia.
Another factor that influences the success rate of surgery is how long a person has had Type 2 diabetes when they have surgery. Those who have had diabetes for less than three years before undergoing weight loss surgery stayed in diabetes remission the longest.
Controversial research has suggested that even people with Type 2 diabetes who aren’t obese may benefit from surgery.
This is because weight loss surgery often improves Type 2 diabetes, even before patients start to lose weight. The rapid remission of Type 2 diabetes after gastric bypass surgery — independent of weight loss — is one of the most enticing discoveries about weight loss surgery. Why this occurs is a subject of current research.
Some researchers believe it is due to GLP-1, a hormone made in the lower small intestine that helps with blood glucose control and weight loss. The diabetes medication exenatide (Byetta) works by behaving like GLP-1. Studies have shown that blood GLP-1 levels increase after weight loss surgery.
Solving the mystery of how weight loss surgery puts Type 2 diabetes into remission could provide the basis for powerful new diabetes medications. In the absence of such a breakthrough, the question at the heart of the debate is: Who stands to benefit the most from surgery, and who should stick with a more traditional treatment of diet, exercise, and medication?
Weight loss surgery has to work in tandem with lifestyle changes. It reduces portion size, causes some malabsorption of calories and alters some of the hormones. However, it is not a “magic bullet”. The 60-80% of excess weight loss it achieves over a 12-18 month period allows someone who has been struggling with obesity the time to modify their diet and exercise to achieve a healthy lifestyle.
What are the downsides?
Weight loss surgery has a much higher upfront costs compared to medication and lifestyle modification. However, those costs can be recouped in as little as four years in patients with Type 2 diabetes.
Long-term follow-up is necessary. Patients are advised to take regular vitamin and mineral supplements to prevent micronutrient deficiencies and bone disease. To avoid this, I typically review my patients at least yearly.
As with any surgery, there is the risk of a surgical complication: bleeding, infection, leak, cardiac event, blood clot or damage to other organs. However for comparison, the overall level of risk for a gastric sleeve (the most commonly performed weight loss procedure) is similar to having a gallbladder removed and less than having a joint replacement. This has to be weighed against the risk of medical complications from the continued combination of obesity and Type 2 diabetes.
What’s the bottom line?
Weight loss surgery offers an opportunity for those with Type 2 diabetes to put their disease into remission. That is, living their day-to-day life with no medication, no insulin. With well-controlled blood sugars they reduce the damage being done to their eyes, kidneys, heart, blood vessels, teeth and nerves.
Patients now have an opportunity to decide if they want a lifetime of medical management or a surgical procedure.
I think people are entitled to be given a choice, to be educated about the possibilities that exist today.