Most recent update: Wednesday, December 11, 2019 - 08:39

Bariatric News - Cookies & privacy policy

You are here

Diabetes - prevention is better than cure

In a recent paper, Australian researchers reported that bariatric surgery may be an effective diabetes prevention strategy for paitents with impaired fasting glucose. Here, co-author of the study, Professor Paul O'Brien, discusses the possible implications of the findings...

Prevention is better than cure. Yet, in medicine, we get so few opportunities to truly prevent new diseases. This study indicates such an opportunity. And it is a big one, the prevention of diabetes!

The International Diabetes Federation estimates 382 million people are living with diabetes today. Diabetes contributes heavily to the illnesses, mortality and healthcare costs of the community. The number of people with diabetes continues to grow rapidly, an epidemic that is linked to the rising rates of obesity. Diabesity is a real entity.

With prediabetes you are in the diabetes waiting room. The Diabetes Prevention Program1 informs us how soon you will be called. They had a control group with prediabetes, with a mean BMI of 34 and no treatment. The group showed an 11% likelihood of progressing to diabetes each year.  So, if you are obese and have prediabetes today, you have a better than 50% chance of having diabetes within 5 years. Then you will be subject to all the consequences of that disease.

Weight loss will reduce your risk markedly.

There were two key findings arising from the prediabetes study which we have just published.

The first was the profound effect of weight loss on the risk of progressing to diabetes. We performed gastric banding on 281 people with prediabetes and a mean BMI of 46. We then followed them for a mean of 4 years.  We compared them with a group of people with prediabetes and a mean BMI of 34 who did not have weight loss. For the weight loss group, there was a hazard ratio of 0.25, a 75% reduction in the relative risk of progressing to diabetes. 

It probably doesn’t matter how the weight loss is achieved. In this study we used gastric banding. Others have used lifestyle programs1 or other forms of bariatric surgery2.

There have been a number of diabetes prevention programs conducted across the world. The Diabetes Prevention Program is perhaps the best known2. It was a randomized controlled trial involving 3234 participants who were overweight and had prediabetes. The main test group had lifestyle interventions with encouragement to eat less, do more and change behaviour. This group managed only modest weight loss, a mean of 4 kg at three years, but had a reduced incidence of diabetes with 4.8 cases per 100 patient.years compared to 11 cases per 100 patient.years in the no-treatment group, a 58% reduction. Nevertheless, it needed 7 people to participate in the lifestyle program for one person to be saved from diabetes during the three year period. Probably that is worthwhile, but it might be hard to sustain.

The Swedish Obese Subjects (SOS) study2 compared the development of diabetes in their 1,658 surgical patients with a concurrent control group of 1,771 obese people over a much longer period. The hazard ratio for the surgical group was 0.22, indicating a 78% risk reduction, essentially the same as in our study. The surgical procedures included an earlier form of gastric banding, vertical banded gastroplasty and gastric bypass. The individual hazard ratios for each surgical procedure were not different, suggesting the type of surgery is not as important as the weight loss.

The second key point is that the amount of weight loss does matter a great deal. The patients in our study lost an average of 25 kg or 19% loss of their total weight. When divided into tertiles, those in the highest weight loss tertile, who had a mean of 32% TWL, had almost complete protection. Just one of 93 patients developed diabetes and that only appeared after a complex series of problems and surgeries to the pancreas following gallstone pancreatitis. But the lowest weight loss tertile, with just 6% TWL, were not different from the control patients. And, of course, that weight loss must be durable. Regaining the weight is regaining the risk. Happily, most but not all forms of bariatric surgery have proven durability, at least in excess of ten years3

And so, via substantial weight loss, we have an opportunity to make a difference.  Let’s take it.

The following steps are indicated:

  1. Identify the presence of prediabetes in the obese. If the fasting blood sugar is between 6 and 7 mmol/L, prediabetes is present. Alternatively, use a HbA1c between 5.7 and 6.4%
  2. Look for the other features of the metabolic syndrome – central obesity, elevated blood pressure, high triglycerides and low HDL cholesterol. Their presence makes the argument for weight loss even stronger.
  3. Impress upon the patient the risk of progression, the morbidity of diabetes and the opportunity for prevention.
  4. Offer weight loss. Start with methods that are simple and safe and move up the scale of invasiveness only as needed. Start with lifestyle intervention then drug therapy and very low energy diets. Next consider gastric banding.  For some, there could be a need to progress to gastric bypass or sleeve gastrectomy.
  5. Maintain follow up, maximizing the weight loss, ensuring its durability and monitoring the relevant biochemistry.

This is secondary prevention at its best. We have missed the opportunity for primary prevention, for stopping the obesity occurring.  But by anticipating harmful effects of obesity, we can detect its seeds of destruction starting to germinate and we can stop them flowering.

References

  1. 1. Diabetes Prevention Program Research G. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. New England Journal of Medicine. 2002;346:393-403
  2. 2. Carlsson LM, Peltonen M, Ahlin S, Anveden A, Bouchard C, Carlsson B, Jacobson P, Lonroth H, Maglio C, Naslund I, Pirazzi C, Romeo S, Sjoholm K, Sjostrom E, Wedel H, Svensson PA, Sjostrom L. Bariatric surgery and prevention of type 2 diabetes in swedish obese subjects. N Engl J Med. 2012;367:695-704
  3. 3. O'Brien P, McDonald L, Anderson M, Brennan L, Brown WA. Long term outcomes after bariatric surgery: Fifteen year follow up after gastric banding and a systematic review of the literature. Annals of Surgery. 2013;257:87-94