Saturday, December 29, 2012

Does bariatric surgery cure diabetes?


Bariatric surgery has been heavily promoted to treat Type 2 diabetes. Bariatric surgery is now being considered for those with less severe obesity, a body mass index (BMI) less than 35.

Surgery generates a lot of revenue for surgeons and the hospitals where they work. The Lap-Band System generates substantial revenue for its manufacturer. But just how effective is bariatric surgery for diabetes?

Does bariatric surgery cure diabetes? For the sake of clarity, let’s use the term "complete remission" instead of "cure".

The definition of complete remission of diabetes has been agreed upon to mean normal blood glucose measurements lasting at least a year without the need for medications.

It has been known for decades that weight loss dramatically improves glucose levels in persons with Type 2 Diabetes.

Modest weight loss of even 5% reduces the need for medication to treat the diabetes.

With weight loss, insulin works better and the pancreas can produce more insulin. 
The amount of weight lost appears to be the main reason for the improvement in glucose after weight loss surgery.

A recently published trial called STAMPEDE was conducted at the Cleveland Clinic. This trial received a lot of media coverage. You might know that the "clinic",  as it is known in Cleveland,  has an outstanding marketing department. 
The goal of STAMPEDE was to test whether bariatric surgery was better than “intensive medical therapy” to control blood glucose in obese adults with Type 2 Diabetes.

The average BMI was 36 before surgery. 
A third had a BMI less than 35.
And either sleeve-gastrectomy or gastric bypass surgery was performed.

The investigators started off with 150 patients and determined the likelihood of these patients getting to a Hemoglobin A1c of less than 6% after 12 months. Now, a HgbA1c of less than 6% is really good blood glucose control and is lower than our goal for most patients with Type 2 Diabetes.
Patients were randomly assigned to one of the surgical treatments or to the so called "intensive medical therapy".

This study had obvious flaws that most people fail to see.
The main flaw is calling the medical therapy “intensive medical therapy”. This "intensive" treatment was a visit to the clinic every 3 months. That’s a joke! 
That is not intensive therapy!

The intensive therapy in the 10, 000 person ACCORD trial which also targeted a Hemoglobin A1c below 6% meant a visit every 2 weeks for 4 months and then at least monthly. And at the visits treatment was really intensified.

In STAMPEDE, there was minimal increase in the use of medications despite this supposed "intensive" therapy.  
STAMPEDE appears to have been designed by the surgeons to show that surgery was better.  
Well,  it clearly suggested that surgery is better than minimal medical therapy.  

And in this Cleveland Clinic trial, among those who had surgery, 22% in the gastric bypass group were still on medication for their diabetes at 12 months. And that number was 49 % for those who had undergone a sleeve gastrectomy!
And a recent analysis of 357 patients with Type 2 Diabetes who had  a BMI less than 35  before surgery found that about 20% fail to go into remission after surgery.

And another large recent analysis  of over 4400 patients who underwent gastric bypass showed that about 32% failed to have a complete remission of their diabetes within 5 years. These people were not “cured” of their diabetes. And of those who did have a complete remission, about 35% saw their diabetes come back within the next 5 years.

Those persons most likely to have a complete remission were those before surgery who were not using  insulin and those who had  shorter duration of their diabetes. 
Another recent large study of diabetes remission among over 1100 patients showed that 38 % still had diabetes 6 years after gastric bypass surgery.

So taken together these studies tell us that about 40% or more adults still will have to deal with treatment of their diabetes despite having had bariatric surgery.

Bariatric surgery helps many patients in many ways but it  is no "cure all" for Type 2 Diabetes.

Every treatment for diabetes has its pros and cons. 
And that includes surgery which does not “cure” diabetes in a significant number of patients. 
Daniel Weiss MD CDE FACP PNS CPI
Your Diabetes Endocrine Nutrition Group













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