Gastric bypass surgery is a procedure used for treating severe obesity. The procedure, which has also been performed in many patients with diabetes, is associated with a remarkable improvement in blood glucose levels even before any real weight loss has taken place. Gastric bypass surgery has now been suggested to represent an ideal opportunity to ‘cure’ type 2 diabetes even in mildly overweight patients rather than just the morbidly obese.

Weight management programmes usually start by a detailed assessment of nutrition and exercise. Despite advice on these issues many people fail to achieve any meaningful weight loss and may turn to weight loss medication. Some benefit can be demonstrated over time with these but the weight loss is often only modest and not significant enough to alter the natural history of type 2 diabetes.

Bariatric surgery for diabetes patients was introduced originally as a weight management procedure. There is choice in the surgical technique including the placing of a gastric band or performing a more extensive operation which is known as a gastric bypass. Both can be performed by keyhole surgery and both result in weight loss. Gastric banding is often preferred because it is easier and reversible. Improvements in diabetes control following gastric banding are gradual and seem to mirror the slow weight loss achieved with time.

This is in contrast to gastric bypass where re-routing the intestine appears to be associated with an almost immediate improvement in blood glucose levels. Many patients can leave hospital soon after the procedure without needing any of their hypoglycaemic medication. This may even have included a stack of pills in combination with insulin injections. Research into the reasons why has demonstrated alterations in the levels of gut hormones following surgery and it has been proposed that this in some way improves the secretion and sensitivity to insulin. Longer-term studies are currently suggesting a figure of about 80 per cent of patients treated with a gastric bypass being cured of type 2 diabetes.

The whole area of bariatric surgery is not without its critics and controversies. Some clinicians point to the very significant and necessary nutritional changes after having a gastric bypass as the prime reasons for the improved diabetes control. That the procedure actually works both for weight loss and improved blood glucose levels is not, however, in doubt. Controversy does exist as regards a weight cut off threshold for treatment. Should bariatric surgery be available to everyone with diabetes? Who exactly is an ideal candidate for bariatric surgery? Is it ethical to offer a technique with a low but nonetheless defined surgical risk to treat a disease that we can manage medically?

With all this to think about patients and their doctors often end up considering the risks of doing something surgical against the risks of not doing it. There is no doubt that obesity itself carries with it a very significant morbidity and mortality. Diabetes related complications add to what may now sound like a rather gloomy outlook. It is often on this basis that the decision to go ahead with bariatric surgery might be first entertained.

It is only after many years of study that the effects of such a drastic change to intestinal transport and nutrition can be appreciated. Much more research is needed but for the time being bariatric surgery remains a valid and appropriate option for selected patients.

Read more about Bariatric surgery in Weight & Diet