Diabetes goes under the knife – Expert reaction

New guidelines recommend surgical treatment for obese patients with type 2 diabetes, but researchers say New Zealand lacks the resources and capacity to offer surgery as a standard treatment.

Surgery and emergency conceptA joint statement by international diabetes organisations endorses gastric and bariatric surgery as a standard treatment option for type 2 diabetes for patients with very severe obesity (a body-mass index (BMI) of over 40). The new guidelines also recommend that surgery be considered for patients with less severe obesity who are unable to control their blood sugar through other treatments.

Gastrointestinal surgery has been used as a weight management tool in obese patients, many of whom have diabetes, but has not been recommended as a direct treatment for diabetes until now.

The clinical guidelines, published in the journal Diabetes Care, were developed at a conference last year and have been endorsed by 45 medical and scientific societies. The New Zealand Society of the Study of Diabetes did not endorse the guidelines (see comment below).

Writing in Nature, the lead author of the guidelines Francesco Rubino said the reccomendations might be “the most radical change in the treatment of type 2 diabetes for almost a century.”

“This development follows multiple clinical trials showing that gastrointestinal surgery can improve blood-sugar levels more effectively than any lifestyle or pharmaceutical intervention, and even lead to long-term remission of the disease,” he wrote.

The SMC collected the following expert commentary.

Assoc Prof Jeremy Krebs, Immediate Past President of NZSSD and Member of the Healthier Lives Science Advisory Group, comments:

“The executive of  the New Zealand Society of the Study of Diabetes (NZSSD) was approached by [lead author] Prof Francesco Rubino in April requesting endorsement by the society as a representative of New Zealand. The Society responded as below. This was after a discussion at an executive meeting and seeking the opinion of several senior endocrinologists throughout New Zealand. I believe that this response summarises the consensus opinion.

“Whilst there is general support for the place of bariatric surgery in the management of people with type 2 diabetes who are obese, the consensus view of the executive was that there are important differences in the funding structure and access to treatments including medications and surgery in New Zealand compared with the UK, Europe and the USA that mean that we cannot fully endorse these recommendations as they stand. We recognise that it is impossible to create a document that meets all the competing interests of different countries, and we applaud the great work you have done to pull this together.

“Our particular concerns relate to the recommendation for those with a BMI of >40 to be expedited to surgery, and the lack of emphasis on dietary intervention in those with a BMI of 30-35, prior to considering surgery. With limited public funding for bariatric surgery in New Zealand it would be difficult to justify calls to prioritise this group particularly for surgery.

“However, we do support a position paper encouraging the inclusion of bariatric surgery as part of the treatment options specifically to manage diabetes, and not only for managing obesity per se. We will therefore plan to follow up on the publication of your paper with a position statement on our website and an editorial submitted to the New Zealand Medical Journal. We are also contributing to a current review of the NZ obesity guideline at present and will endeavour to incorporate many of your proposed recommendations in that.”

Dr Rinki Murphy, Specialist Diabetes Physician and Senior Lecturer at the University of Auckland, comments:

“This position paper does well to encourage the inclusion of bariatric surgery as part of the treatment options specifically to manage diabetes rather than focussing on its role solely in obesity.  Hopefully, this will encourage more equitable access to bariatric surgery in New Zealand. Disparities in patient selection, patients choice, and negative societal attitudes to obesity and bariatric surgery, may be some of the reasons for low uptake of surgery in certain ethnic groups – particularly under-representation of Pacific people.

“In my view, bariatric surgery should be routinely discussed with adult patients with high BMI [Body Mass Index] and type 2 diabetes, who do not have surgery safety contraindications such as ischaemic heart disease, cirrhosis, renal failure.

“The current prioritisation for publicly funded bariatric surgery in NZ includes those with BMI of 40kg/m2 or more, or BMI 35-40 if they have another significant disease which is expected to improve significantly with surgery e.g.: type 2 diabetes, sleep apnoea, or arthritis requiring joint replacement.  It presently does not include consideration of patients with inadequately controlled T2D with BMI 30-34.9 as stated in these guidelines, largely due to implementation and capacity limitations.

“The success of medically supervised very low calorie diet with behavioural management support in achieving significant weight loss and comorbidity reduction has been documented in a recent systematic review and meta-analysis of several randomised controlled trials. This approach requires further evaluation in comparison to bariatric surgery in the group of patients with Type 2 diabetes with BMI 30-34.9.”

Prof Jim Mann, Professor of Human Nutrition and Medicine, University of Otago, comments:

“There are really two bottom lines. First, in most District Health Boards in New Zealand it is very difficult to get bariatric surgery even for people with a BMI over 40 who have comorbities such as diabetes. The first priority in NZ is therefore to ensure that they are considered for surgery, especially when there has been compliance with other measures (including diet) and they have failed to respond adequately.

“In many European countries, the USA, and I suspect in the private sector here, many people in this category receive surgery regardless of whether they have made a serious attempt to change their lifestyles – and this can cause problems because post operative success depends to a considerable extent on long term dietary compliance.

“Second, I am not fully persuaded that the evidence base suggesting long term benefits of bariatric surgery over other treatments (e.g. very low calorie diets) is particularly strong. This applies especially to those whose BMI is at the lower end of the “obese” range, viz 30 – 35.

“So, let’s concentrate on getting bariatric surgery in the public sector for those who are most likely to benefit and establishing with a greater degree of certainty whether those with mild and moderate obesity will also derive greater long term benefit than they would from cheaper and safer options.”