Diabetes and gastric sleeve

A big thank you to Tracy who emailed me asking about diabetes and gastric sleeve surgery. She was wondering what the outcomes were after surgery – does a sleeve ‘cure’ diabetes or reduce blood sugar levels? And what happens with medication throughout the process? So here goes…

What is the link between Obesity and Diabetes?

Whilst obesity and type 2 diabetes are not mutually exclusive, the risk of developing type 2 diabetes is increased 93-fold in women and 42-fold in men who are severely obese rather than of healthy weight. We also know that even a modest weight loss of 5-10% of body weight will lead to significant improvements in blood sugar control. The problem is, due to the complexity of obesity, once you get to a certain size, it is extremely difficult to lose weight and keep it off in the long term with diet and exercise alone.

Will a gastric sleeve improve your diabetes? 

Undoubtably yes. In fact, in 2011, the International Diabetes Federation has recommended bariatric surgery as an appropriate treatment for type 2 diabetes in people with a BMI of over 35 or over 30 if their diabetes cannot be controlled well enough with other medical treatment (an HbA1c >7.5%).

How about cure it? 

There are several studies looking at “remission” or “resolution” of diabetes (we don’t use the word ‘cure’) after surgery. One specific study, The Swedish Study, showed a 72% remission at 2 years post op (compared to 21% of the control group) and 36% remission at 10 years post op (compared to 13% of the control group). Another study, albeit with more flaws, showed 62% of people with diabetes at the time of surgery remained in remission for more than 2 years post op. Bear in mind that these studies are not specific to a sleeve only, and also include other bariatric surgeries such as bypass and banding.

To look at diabetes and sleeve gastrectomy specifically, a review study published in 2016 concluded that a sleeve gastrectomy “is an effective long-term metabolic surgery for patients with T2DM”. When they analysed 11 different studies and looked at 402 sleeve patients with diabetes pre-op, they found that “Diabetes prevalence decreased post-operatively to 20.5 % at 5 years, with diabetes resolution occurring in 60.8 % of patients”. They also reported that HbA1c levels fell from 8.3% to 6.7% on average at the 5-year mark. This study was great, as before then we didn’t really know what happened in the long term with diabetes and gastric sleeve patients specifically.

To sum everything up, the IDF’s position statement on bariatric surgery says”

“Several gastrointestinal (GI) operations that were originally designed to treat morbid obesity also cause dramatic improvement of type 2 diabetes and can effectively prevent progression from impaired glucose tolerance to diabetes in severely obese individuals. …and several reports have documented an improvement of overall survival and specific reduction in diabetes-related mortality.”

As an added bonus, bariatric surgery, including a sleeve gastrectomy has also been shown to improve high blood pressure and cholesterol as well as sleep apnoea, which is fabulous if you have more going on than just diabetes.

So what does this mean for your diabetes and gastric sleeve?

Image: Sutter Pacific Medical Foundation

These stats sound great, and they are. But it’s important to remember the effect of surgery on type 2 diabetes will depend on your history and previous control of the disease. Obviously, commitment to modifying your diet and being active, as well as regularly checking in with your team, including your endocrinologist, will influence outcomes as well.

What we do often see is that people with diabetes and gastric sleeve surgery will reduce their medication and their blood sugar levels will improve – partly to do with the weight loss, but also partly to do with the small portions you can eat (meaning you can’t have a large portion of carbohydrates at once like you used to be able to) and also due to the hormonal and metabolic changes caused by the surgery.

Some patients with more mild diabetes will come off their medication during the pre-op diet phase and never restart, but sometimes they will – and it’s hard to know exactly what will happen for you. It’s always worth discussing this with your surgeon, endo, GP and dietitian, especially before you start the pre-op diet, to avoid any hypos – they will know you best and will be able to monitor your blood sugars and tell you what to do.

I’d be keen to hear from you – have you had good results in terms of your diabetes since your sleeve?

Also – if you’re thinking about or have another type of surgery, like a bypass or band, this is a great summary of the effect of all surgeries on diabetes from the ASMBS.