Skip to main content

26-07-2017 | Metabolic surgery | Editorial | Article

Why don’t we offer bariatric surgery to more people with diabetes in the UK?

John Wilding



Since Walter Pories published his landmark paper in 1995 with the provocative title “Who would have thought it? An operation proves to be the most effective therapy for adult-onset diabetes mellitus” [1], there has been considerable controversy about the place of bariatric surgery in the treatment of type 2 diabetes. Advocates of surgery point to the rapid improvement in glucose control, low surgical complication rates, and a host of other benefits including improved quality of life. Detractors point to problems such as dumping (rapid gastric emptying), hypoglycemia and nutritional deficiencies, as well as lack of persistence of diabetes remission in some patients. Who is right and should we be offering more people with diabetes bariatric or “metabolic” surgery as a treatment option?

The evidence for and against surgery

There is accumulating evidence from large prospective observational studies, such as the Swedish Obese Subjects Study [2], that people with severe obesity and type 2 diabetes have better outcomes than those managed medically, both in terms of weight loss, glucose control, and diabetes complications over a 20-year follow-up period. These encouraging observations are now supported by well-conducted randomized controlled trials of surgery versus medical management that have followed up patients for up to 5 years, have included patients with lower body mass index (BMI), down to 27 kg/m2 and shown better glucose control, as well as improvements in other cardiovascular risk factors, improved quality of life, and a low rate of severe complications. Limitations of these trials include the fact that they were conducted in highly selected patients who were willing to be randomized to surgery or medical treatment, relatively small numbers and lack of long-term follow-up for diabetes complications [3, 4]. Furthermore, it should be recognized that the control groups in these trials did not receive intensive weight management or the most recent medicines such as sodium glucose co-transporter 2 inhibitors and glucagon-like peptide-1 receptor agonists that help patients with diabetes lose weight as well as improve glucose control. Finally, it has to be remembered that surgery may lead to complications for some patients. This may include anastomotic leaks, ulcers, and internal hernias that may require further surgical intervention as well as nutritional deficiencies and hypoglycemia. Like those with diabetes, people who have had bariatric surgery require life-long follow-up.

What do the guidelines tell us?

Although guidelines are strongly supportive of bariatric surgery for those with severe and complex obesity (BMI >40 kg/m2) in people with diabetes, they are more circumspect in those with less severe obesity, where the risk–benefit equation may be different. However, the most recent advice from both the joint Diabetes Societies [5] and the National Institute for Health and Care Excellence (NICE) in England [6] recommend surgery as an option for those with severe obesity and diabetes and support consideration of surgery at a BMI of 30 kg/m2 and above for those with difficult to control hyperglycemia.

Will more patients accept surgery as an option?

Despite this evidence and the supporting guidance, uptake rates for bariatric or metabolic surgery remain very low in the UK compared with other countries. NICE guidance published in 2014 showed both clinical and cost-effectiveness well within the usual NICE threshold of £ 20,000 per quality-adjusted life year (QALY) gained of between £ 2000 and £ 4000, yet rates of bariatric surgery are actually falling, with only 5016 procedures in England in 2015/16 [7], and about a quarter of these being carried out in people with diabetes. There are over 3 million people with type 2 diabetes in the UK, and over a million with severe obesity, so it is clear that most patients will not be offered surgery. To meet the European average of surgery cases per head of population the number of procedures would have to increase 10-fold to approximately 50,000 per year [8]. 

Low rates of uptake in the UK partly relate to the way that obesity care is structured; to access bariatric surgery patients have to be assessed by a specialist multidisciplinary team and show that they have made reasonable attempts to lose weight with lifestyle support (and, if appropriate, medication). There are many areas of the country where these services do not exist, and in many cases, even where services exist, patients are simply not referred by their GPs, so find it hard to access surgery. This problem has recently been exacerbated by changes in commissioning. Bariatric surgery was previously centrally commissioned by NHS England; since April 2017, this responsibility has now moved to Clinical Commissioning Groups which has introduced delays in referral and sometimes additional barriers or altered criteria such as a higher BMI threshold [7]. This effectively creates rationing of what is considered by some as an expensive procedure in the short-term, as it takes several years before the investment is recouped with better outcomes; this does not help in a system that is geared towards making quick (ie, in-year) savings. 

Patient factors may also be important; a study conducted recently in the USA asked people with type 2 diabetes and a BMI between 30 and 40 kg/m2 for their views about bariatric surgery as a treatment [9]. Only 20% of those who responded considered surgery to be a safe and effective treatment for their diabetes, with the authors suggesting that a lot more education and awareness was needed among patients. Although similar data are not available yet for the UK, the authors’ experience supports the view that such misconceptions are common in people with diabetes, so many are not aware of the potential benefits of surgery.


Metabolic surgery is an effective treatment for diabetes, but there are many barriers to its widespread adoption as mainstream therapy. This includes the perception of healthcare providers and patients about its long-term efficacy and safety, concerns about costs, and the need for long-term follow-up that effectively converts a patient with a long-term condition (diabetes) to a post-bariatric surgery patient, also needing some long-term care. Although advances in medical therapy may eventually render surgery obsolete we remain some way from that point, and it would make sense to try and ensure that surgery is at least considered in a wider group of people with diabetes than it is at present.


New additions to the Adis Journal Club

A selection of topical peer-reviewed articles from the Adis journals, curated by the editors.

EASD Annual Meeting 2021 coverage

Access all of our ongoing coverage including the latest news and expert video interviews.

Image Credits