Diabetic Ketoacidosis After Bariatric Surgery in Type 2 Diabetes

Diabetic ketoacidosis (DKA) is a potentially life threatening complication that can occur in people with diabetes.  While we typically associate DKA with type 1 diabetes, it can also rarely happen in type 2 diabetes.   DKA can occur if insulin levels are low, and can be precipitated by a stress on the body, including infection or illness, dehydration, heart attack, and so forth.

A case series was recently published, describing four cases of DKA after bariatric surgery, in three people with type 2 diabetes.   The average time to presentation of DKA was 13 days after surgery (range 3-27 days). All patients were on insulin prior to surgery.  Factors contributing to DKA included omission of insulin and dehydration.

One of these patients was on canagliflozin prior to surgery.  Canagliflozin is a medication in a class of type 2 diabetes medications called SGLT-2 inhibitors, which slightly increase the risk of DKA, particularly if insulin is not taken as directed by the health care team.  Also, if a person taking an SGLT2 inhibitor becomes unwell or dehydrated for any reason while taking the medication, this increases the risk of DKA.  The DKA case in the patient on canagliflozin in this study also had omission of insulin and poor food intake post operatively as contributory factors.

These findings teach us the following:

1.  Patients with type 2 diabetes having bariatric surgery need to be followed closely postoperatively, with meticulous attention to blood sugars and insulin needs.  Some people with type 2 diabetes who were on insulin before surgery do not require insulin after surgery, but others do.   There must also be a low threshold for concern if they become dehydrated due to difficulty tolerating oral intake.

2.  SGLT2 inhibitors should be stopped prior to bariatric surgery (possibly before starting any low calorie diet plan), and if there is still a need for medication to control blood sugar post op, it should not be restarted until the patient is eating and drinking well after discharge home from surgery.

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www.drsue.ca © 2016

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What The Biggest Loser Teaches Us About Metabolism After Weight Loss

Well, I never thought I would say this, but the show The Biggest Loser has been useful for something: it has taught us some important scientific lessons about just how much, and for how long, metabolism drops after weight loss.

(I say that the show is useless otherwise for a host of reasons: It portrays unsafe, dramatic means of weight loss that are not sustainable and gives many incorrect and inappropriate messages about obesity.  I could go on...)

Fourteen participants of The Biggest Loser agreed to have their metabolism measured before the weight loss program, at the end of the 30 week competition, and again 6 years later.

The study was conducted at the National Institute of Health and published in the medical journal Obesity.  The baseline weight amongst these six men and eight women was 148.9kg, and they lost an average of 58kg at the end of the 30 week competition.   After 6 years, most participants regained a significant proportion of the weight lost during the show, with only one person not regaining any weight, and five people having returned to their baseline weight or above.

When they measured metabolism in these people before the competition and compared it to their metabolism 6 years later, they found that on average, their metabolism burned 499 fewer calories per day, compared to what would be expected for a person of that gender, age and body composition who had not previously lost weight.

Similar to an older study I previously blogged about, this teaches us that metabolism decreases markedly after weight loss, not only due to carrying around less weight, but also due to an additional, evolutionarily designed adaptation to defend our body weight. For The Biggest Loser contestants, this means that on average, they have to eat 500 calories less, every day, than they would if they weighed the same but had not come down from a higher weight in the past.  This metabolic adaptation goes on for at least six years after weight loss (based on this study) - and of course may well go on much longer, possibly indefinitely.

So how does a person handle this new lower metabolism after weight loss, to keep the weight off?  We can look to the American National Weight Control Registry to learn about habits that are associated with keeping weight off - the themes are lots of activity (at least an hour a day) and lots of self monitoring - read more on this here.

If you'd like to read more about The Biggest Loser study and the individual participants, the New York Times wrote an excellent article about it, including interviews with several participants - check it out here.

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Type 2 Diabetes Medication Semaglutide Reduces Cardiovascular Risk

Great news from the diabetes world: semaglutide, a medication in development for the treatment of type 2 diabetes and obesity, has been shown to reduce the risk of cardiovascular events.

The SUSTAIN-6 study (a study in which I was an investigator) was a global study of about 3,300 people with type 2 diabetes, who were randomized to receive semaglutide subcutaneously (injected under the skin) once weekly vs placebo for treatment of their diabetes. They found that after 2 years of treatment, semaglutide reduced cardiovascular events (defined as a sum of non fatal heart attack, non fatal stroke, and cardiovascular death).  Exactly how much the risk is reduced is not yet public knowledge - the information is currently available in a press release only, with the exact data to be released at a later date.

Semaglutide is a GLP-1 receptor agonist, which helps the pancreas control the release of hormones involved in blood sugar control (insulin and glucagon), and also stimulates the fullness centre in the brain to tell a person that they feel full.  Thus, not only does it help with blood sugar control, it is also effective for weight loss.  Semaglutide is currently in development as both a type 2 diabetes treatment and as a treatment for obesity in people with or without diabetes (it is not yet available as a prescription).   Interestingly, while all GLP-1 receptor agonists currently available are administered by injection under the skin (similar to how insulin is administered), semaglutide is also currently under development as an oral medication. (ie as a pill)

This marks the third time in the last eight months that we have been so thrilled to hear that a medication designed for the treat type 2 diabetes decreases the risk of cardiovascular events: empagliflozin (trade name Jardiance) (read here) and liraglutide (trade name Victoza) (read here) reduce cardiovascular events as well.  These are landmark times for the world of type 2 diabetes, as prior to these studies, we had not definitively proven that a medication for treatment of type 2 diabetes could decrease the risk of cardiovascular events.  In fact, we have had great difficulty proving that improving blood sugar control by any means reduces cardiovascular events (though it is clear that improving blood sugar control reduces the eye and kidney complications of diabetes).

Amongst the class of GLP-1 receptor agonists, both liraglutide and semaglutide have shown that they reduce cardiovascular events (though the numbers on this are not yet available on either one), whereas lixisenatide (not available in Canada) did not decrease cardiovascular events.  It remains to be seen what effect the other GLP-1 receptor agonists available in Canada have on cardiovascular events (exenatide (trade names Bydureon and Byetta) and dulaglutide (trade name Trulicity)) - these studies are still underway.


Disclaimer: I am involved in research trials of semaglutide for type 2 diabetes and obesity.  I receive honoraria as a continuing medical education speaker and consultant from the makers of liraglutide (Novo Nordisk). 

Follow me on twitter! @drsuepedersen

www.drsue.ca © 2016

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