Weight loss surgery beats lifestyle changes for obese people with diabetes

A new study by Australian researchers offers strong support for laproscopic adjustable gastric banding (LAGB) as an effective therapy for type 2 diabetes. The study provides evidence that LAGB can reverse type 2 diabetes in obese patients diagnosed with the condition. The study is significant because it is the first to compare weight loss surgery with conventional management of diabetes using a randomized controlled trial. The results of the study are clearly weighted in favour of LAGB over lifestyle changes. The most important finding was that the remission rate for diabetes was five times higher in obese patients who underwent surgery.

The Australian study, published in the Journal of the American Medical Association (JAMA),¹ was led by Associate Professor John Dixon of Monash University and colleague Professor Paul O’Brien, Head of the Centre for Bariatric Surgery. The study was undertaken at the Centre for Obesity Research and Education (CORE) at Monash University in Victoria.

Observational studies had suggested that surgically induced weight loss could lead to better outcomes for obese patients with type 2 diabetes. However, there was no empirical evidence that surgery was more effective than conventional approaches to diabetes management. A team of researchers decided to investigate this question, and designed an unblinded randomised controlled trial which would continue over a period of 3 years. The participants were 60 obese patients who had recently been diagnosed with type 2 diabetes.

Participants were separated into two groups – those who underwent LAGB and those who continued conventional diabetes therapy and were encouraged to lose weight through lifestyle changes. The effectiveness of each approach was measured by rates of remission of type 2 diabetes. ‘Remission’ was defined as having a fasting blood glucose level of 7.0 mmol/L and a glycated haemoglobin value of <6.2% while taking no glycaemic therapy. Researchers also examined weight and components of the metabolic syndrome.

The results of the study were conclusive. Obese patients who underwent LAGB surgery were five times more likely to have their diabetes go into remission. There was a significant difference between weight loss achieved by the different groups. In those who had the surgery, there was a 20% loss of body weight. In contrast, an average loss of only 1.4% was recorded by the patients who changed their lifestyle. The greater weight loss in the surgery group also resulted in a reduction in BMI and in the use of diabetes medications. Even the use of non-diabetes medications, such as those to lower blood pressure and lipid levels, decreased.

The researchers concluded that the participants who had been randomly allocated to the LAGB group were much more likely to achieve remission of their type 2 diabetes. This was primarily because the surgery group achieved significantly more weight loss than their counterparts on conventional diabetes management. This study provides strong support for the use of LAGB as a therapy for type 2 diabetes in obese patients. Although this is a strong first indication, the researchers state that a longer term study is still needed to see if the results are sustainable. It may also be necessary to repeat the study with a larger sample size and a more diverse population.

It is important to stress that this study involved patients who were already severely obese. Since type 2 diabetes is associated with an increased body mass, it can be prevented by maintaining a healthy weight. According to Diabetes Australia (NSW), "There is an urgent need for people to adopt a healthy lifestyle, because type 2 diabetes can be prevented through being physically active and healthy eating."

If this advice is not followed, then Diabetes Australia (NSW) predicts that there will be an explosion of diabetes in Australia in the near future. Most alarmingly, "statistics show that 1.5 million Australians have diabetes and if there is no change to this trend, that number will reach four million by 2012".² These comments highlight the importance of the research at CORE, Monash University, which has shed light on how diabetes can be best managed in obese patients.

References

1. Dixon J, O’Brien P, et al. Adjustable gastric banding and conventional therapy for type 2 diabetes: a randomised controlled trial. JAMA. 2008; 299 (3): 308-15.
2. Comments from Bill Edmond, Corporate Relations & Communications Division Manager for Diabetes Australia-NSW.