Obesity Surgery to Treat Type 2 Diabetes?

At the recent inaugural meeting of the Canadian Association of Bariatric Physicians and Surgeons, I was asked to review the recent consensus statement released by the International Diabetes Federation on the use of bariatric (obesity) surgery to treat patients with obesity and type 2 diabetes. 

(Skip to MY BOTTOM LINES below for a summary, or read through for the nitty gritty!)

The International Diabetes Federation consensus states:

1.  Bariatric surgery is an appropriate treatment for people with type 2 diabetes 
and obesity not achieving recommended treatment targets with medical 
therapies, especially when there are other major co-morbidities.

2.  Surgery should be an accepted option in people who have type 2 diabetes 
and a body mass index (BMI) of 35 or more.  (note - you can calculate your BMI in the right column here)

3.  Surgery should be considered as an alternative treatment option in patients 
with a BMI between 30 and 35 when diabetes cannot be adequately controlled 
by optimal medical regimen, especially in the presence of other major 
cardiovascular disease risk factors.


As I reviewed at the meeting, the literature shows that most patients with obesity and poorly controlled type 2 diabetes experience an improvement in their diabetes with obesity surgery (especially gastric bypass and sleeve gastrectomy).  We have more data for patients with a BMI ≥35 than we do for patients with a BMI of 30-35 at this point in time, but the literature for the latter group is growing. 

A large proportion of patients with type 2 diabetes will go into remission from their diabetes (meaning their diabetes goes away) after bariatric surgery, which of course sounds like a very attractive possibility to the person who has to deal with diabetes on a daily basis.


HOWEVER: 

• Based on the data we have currently available, about half of these cases of diabetes that went into remission after gastric bypass surgery come back by 5 years after surgery (called 'recurrence').
• Almost all of the long term data for diabetes remission rates is in patients with a BMI ≥ 35; there is almost no data to help us understand what the long term recurrence rate of type 2 diabetes is in the BMI 30-35 group.  People who have diabetes with this lower BMI may have a stronger genetic predisposition towards having diabetes, so it is plausible that these people would be less likely to have their diabetes stay away over the long term.
• There is little data to help us understand long term recurrence rates of diabetes after sleeve gastrectomy (which is becoming increasingly popular - read more about the types of surgeries here).
• The definition of diabetes 'remission' was previously quite loose and has now become much stricter; therefore, the remission rates reported in the literature are overinflated.

MY BOTTOM LINES on this controversial topic are:

1.  For people with a BMI of ≥ 35, with POORLY CONTROLLED diabetes:   Bariatric surgery is an option that provides a good opportunity to improve diabetes control.

2.  For people with BMI 30-35, with POORLY CONTROLLED diabetes:  There is very little information to guide us in this group of patients, but so far, it appears that bariatric surgery could provide a good opportunity to improve diabetes control.

3.  For people with BMI of ≥ 35 with GOOD CONTROL of their diabetes: Bariatric surgery can offer an opportunity to make diabetes go away - but for at least half of these patients (and possibly more over the longer term), the diabetes will come back. 

4.  For people with BMI of 30-35 with GOOD CONTROL of their diabetes: Bariatric surgery can make diabetes go away, but we don't yet know what percentage return to diabetes.  Due to genetics, their risk of return to diabetes may be higher than those with BMI ≥35.

5.  Any patient whose diabetes goes into remission after bariatric surgery MUST be followed for the rest of their life for screening for the possible return of diabetes.

And of course, for ALL people who are thinking about having bariatric surgery, the risks and benefits of the procedure as a whole must be carefully weighed by both patient and their health care providers, to decide if this intervention is the right thing for them.



Dr Sue Pedersen www.drsue.ca © 2012 drsuetalks@gmail.com

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PS - Bariatric surgery has been shown to PREVENT development of Type 2 diabetes as well (scientists - recent follow up to the SOS study published in the New England Journal of Medicine) - a story for another day's blog!