Intended for healthcare professionals


Why the NHS should do more bariatric surgery; how much should we do?

BMJ 2016; 353 doi: (Published 11 May 2016) Cite this as: BMJ 2016;353:i1472
  1. Richard Welbourn, consultant surgeon1,
  2. Carel W le Roux, professor of metabolic medicine2,
  3. Amanda Owen-Smith, lecturer in social medicine3,
  4. Sarah Wordsworth, associate professor of health economics4,
  5. Jane M Blazeby, professor of surgery5
  1. 1Department of Upper Gastrointestinal and Bariatric Surgery, Musgrove Park Hospital, Taunton TA1 5DA, UK
  2. 2Diabetes Complications Research Centre, Conway Institute, University College Dublin, Ireland
  3. 3School of Social and Community Medicine, University of Bristol, Bristol, UK
  4. 4Nuffield Department of Population Health, University of Oxford, Oxford, UK
  5. 5Centre for Surgical Research, School of Social and Community Medicine, University of Bristol, UK
  1. Correspondence to: R Welbourn Richard.Welbourn{at}

The number of people getting bariatric surgery is falling despite rising rates of obesity and diabetes. Richard Welbourn and colleagues examine why and argue that better access has potential to reduce long term costs of care

As the epidemic of severe and complex obesity worsens, availability of the most successful treatment, bariatric surgery, is limited. Less than 1% of those who could benefit get treatment. By contrast, people with other lifestyle health problems such as alcohol related liver disease are treated. We explore the clinical and cost effectiveness of bariatric surgery and examine the barriers to access.

Effectiveness of surgery

A Cochrane review of 22 randomised controlled trials of bariatric surgery found that it is more effective and cost effective for the treatment of severe obesity than non-surgical measures after two years.1 Longer term trial data also favour surgery.2 Non-randomised data from the Swedish Obese Subjects study (SOS), a long running cohort study of 2000 patients who received surgery and 2000 matched controls, shows weight loss being maintained for 20 years,3 with glycaemic control improved for at least 10 years after surgery. Patients having surgery were also more likely to go into glycaemic remission of diabetes than those having non-surgical approaches, and fewer patients progressed from prediabetes to diabetes.3

In the UK a national registry of over 3000 patients with diabetes operated on between 2011 and 2013 shows that 65% had acceptable glycaemic control without medication after surgery.4 Swedish registry data also show a 58% reduction in the relative risk of dying during an average of 3.5 years’ follow-up of 6000 patients with diabetes compared with matched patients without surgery.5 In all the surgical series the average weight loss is 25-35% of body weight (usually at least 15 kg) after one year for patients who are severely obese and 15-25% after 20 years.3 This is much greater than the average 7% weight loss achieved by patients attending intensive lifestyle weight management programmes or taking state of the art drugs.6 7

Bariatric surgery is also cost effective compared with non-surgical treatments. A UK health technology assessment found that for patients with a body mass index (BMI) ≥40, the incremental cost effectiveness ratios for surgery ranged between £2000 and £4000 per quality adjusted life year (QALY) gained over 20 years.8 This is well below the £20 000 per QALY threshold for cost effectiveness used by the National Institute for Health and Care Excellence (NICE). For patients with diabetes and a BMI of 30-39 the incremental cost effective ratio fell to £1367 per QALY gained. If a decision maker is willing to pay £20 000 for an additional QALY, the probability of surgery being cost effective over 20 years was reported as 100%.8 These figures are in line with those for other public health interventions such as smoking cessation and statins for primary prevention of cardiovascular disease.9

Economic analysis for NICE confirms that the financial outlay for surgery is justified for the NHS.10 In patients with diabetes, for example, the cost of surgery will be recouped within three years through reduced prescriptions.11 Surgery also has indirect cost benefits. For example, state disability allowances are reduced if improved activity levels allow patients to return to paid employment.12 The UK registry data found that only 28% of patients could climb three flights of stairs before surgery and this improved to over 72% 12 months later.4

Who is eligible for bariatric surgery?

NICE guidance recommends that surgery is considered for people with severe obesity in whom all non-surgical measures have been tried without achieving or maintaining adequate weight loss (box 1).10 13The person must be committed to long term follow-up and behaviour change.

Box 1: Summary of updated NICE guidance on bariatric surgery13

  • Bariatric surgery is a treatment option for anyone with a BMI≥40

  • Offer an expedited assessment for people with a BMI≥35 with onset of type 2 diabetes in past 10 years

  • Consider an assessment for people with a BMI of 30-34.9 with onset of type 2 diabetes within 10 years

  • Consider an assessment for people of Asian origin with onset of type 2 diabetes at a lower BMI than other populations

  • Bariatric surgery is the option of choice for adults with BMI >50 when other interventions have not been effective

  • People fitting the above criteria are also required to be receiving or to receive assessment in a specialist weight management service before referral to a surgical team

In the UK, 1.6 million people have a BMI of at least 40.14 There are at least half a million people with diabetes and other obesity related disease with a BMI ≥35, and lowering the BMI threshold to 30 for recent onset diabetes increases this number to about a million. Therefore at least 2.6 million people meet NICE criteria for surgery.15 16 NICE estimated that about 80% of patients above the BMI thresholds would be medically and psychologically suitable for surgery. About 10% of them might wish to pursue this option.17

The pool of eligible people continues to escalate as an extra 60 000 people a year reach a BMI of 40. The number of people with type 2 diabetes has also increased by 60% over the past decade (to 3.3 million or 5% of the adult population), and 9.5% of adults are predicted to have the condition by 2030 (190 000 new patients each year).18 19

Rates of surgery in the UK and elsewhere

Despite obesity levels increasing, and bariatric surgery being shown to be clinically effective and cost effective, NHS bariatric procedures are falling. Between 2011-12 and 2014-15 the number of operations fell by 31%, from 8794 to 6032.14 20 Provision of surgery in the NHS therefore meets much less than 1% of the need. This is in stark contrast to provision in many European Union countries. The UK has the second highest rate of obesity in Europe, and ranks sixth internationally, with 25% of adults being obese and 62% being overweight (BMI> 25) or obese.14 21 However, it ranks 13th out of 17 for countries for rates of bariatric surgery (about 9/100 000) and sixth in the G8 countries.22 23 Sweden, which has a similar health service but lower obesity rates, performs 70-80 procedures per 100 000 people.24 25 In North America the rate of surgery is around 40-50/100 000, with most of this being in the US.22

Rates of surgery also vary within the UK, with no NHS operations in Northern Ireland and few in Wales and Scotland. Given the severity of the problem, it seems urgent to consider the potential barriers to surgery.

What are the barriers to surgery?

One reason for the low rates of surgery in the UK is that general practitioners (GPs) are unable to refer directly to surgical services. Instead, there is a tiered pathway (table). At the population level (tier 1), low calorie foods and exercise are recommended. Most patients, however, will have been dieting for years, with cyclical loss, reaching a plateau and then regaining weight. They may be reticent to ask for professional help (tier 2) because of previous negative responses from health professionals, low self esteem, or embarrassment.26 Empathetic engagement at primary care level may unintentionally promote these problems, with unsolicited advice such as “eat less and exercise more” being harmful.27 Although GPs receive financial incentives to measure the prevalence of obesity, there are no rewards or targets for giving treatment or referring on for specialist help.

Tiered pathway to bariatric surgery and barriers to access

View this table:

If a GP does refer for weight management this may initially be to a community programme rather than specialist medical or surgical assessment in secondary care (tiers 3 and 4). Tier 3 is a secondary care multidisciplinary team approach. Patients must receive care from a secondary care team for 12 to 24 months before referral for surgery, and the clinics are not available widely.28 29 The interventions offered within secondary care vary and outcomes are not routinely assessed. Thresholds for referral on to surgery are unclear and BMI acceptance criteria also vary between regions.20 30 Some clinics mandate weight loss before surgery, although evidence for this is absent.31 32 This prolonged pathway may create inertia and put patients off accessing effective surgical treatment.28 30 31

There are no contractual mandates to fund secondary care clinics, and from April 2016 local commissioning groups will be free to pursue other obesity treatment strategies (and GPs will still not be able to refer directly to surgical services). Without a clear pathway access to surgery may stop.

Commissioners have also restricted the number of bariatric operations they will fund, despite the evidence of cost saving. This may be because it is an upfront cost, with savings being recouped in subsequent financial years. Indicative numbers of procedures set in each region do not seem to reflect any estimate of clinical need or benefit, and funding has not increased despite considerable advocacy from patients and surgeons.

Another barrier is the perception among patients, healthcare workers, and the media that surgery is high risk. This is despite Hospital Episode Statistics showing a 30 day mortality of 1.7 per 1000 patients, lower than for many more common gastrointestinal operations.33

Prejudice may also affect provision of services. One study from the US showed that changing the name of a bariatric clinic to “metabolic and diabetes surgery” increased the number of male patients.34 Some healthcare workers share societal implicit beliefs that patients with obesity are lazy and bad.35 If encouragement to diet and exercise fails they may assume that patients are to blame for their predicament and do not deserve surgery. Those opposed to surgery often argue that it will detract from prevention, but treating a disease does not prohibit prevention activities. Good examples include the widespread provision of complex and expensive treatments for smoking related disease and traffic collisions, without any detriment to effective prevention programmes.

Which patients should be offered surgery?

It is not possible to operate on every patient fulfilling the NICE criteria and so it seems sensible to target treatment at those with the greatest potential for improved health. Patients who have obesity related diseases that are expensive to treat and who are likely to need less medication afterwards, such as those with recent type 2 diabetes, are an obvious priority.4 10 Alternatively, priority might be given to people with established microvascular complications because despite best pharmacological care many will become increasingly unwell and require more expensive treatment.36 Another option is for the multidisciplinary team to decide based on individual need—for instance, a patient with sleep apnoea falling asleep at work or needing urgent weight loss before kidney transplantation.28

How can we increase rates of bariatric surgery?

Increasing surgery rates to 50 000 a year, which is closer to the European average, could have major benefits for patient health and reduce direct healthcare expenditure within two years, in addition to cost savings in the future from reduced treatment costs.36 37 To achieve this health workers need to leave prejudice behind, promote bariatric surgery, and offer it to people who are unable to succeed with non-operative measures. We recommend initiatives to overcome the barriers such as communication skills workshops for staff, increased dietetic services, investment in multidisciplinary team working, and creation of metrics for quality assessment with external peer review panels (as seen in the NHS Cancer Plan). Adopting the phrase “metabolic surgery” might enable society and patients to talk about it and begin to establish a culture change.

In addition, GPs and commissioners need to recognise the health benefits gained from bariatric surgery (and the cost savings). This will facilitate better provision of secondary care services. We recommend combining provision of secondary care medical and surgical management so that patients have access to surgical assessment earlier.28

Provision of more surgery also requires better long term support and nutritional follow-up (key to the success of surgery). Development of obesity or metabolic care services for surgical follow-up in general practice could also improve care for people not wanting surgery. Given resource limitations, provision of such services may require disinvestment from other conditions such as low risk gall stone disease, inguinal and hiatus hernias. However, a renewed active focus on this large group of patients could limit future costs of treating complications related to obesity and diabetes.

Key messages

  • Bariatric surgery associated with careful follow-up is cost effective for severe obesity and type 2 diabetes

  • Despite clear NICE guidance it is provided for much less than 1% of people who could benefit in the UK and the rate is decreasing

  • Men and minority ethnic groups are less likely to access bariatric surgery

  • Increasing the rate of surgery to 50 000 cases a year would bring the UK in line with other western European countries with similar healthcare systems

  • Closer coordination of surgical, medical, and primary care obesity services is needed to select and support patients for surgery and provide follow-up


  • Contributors and sources: The article was conceived and written by RW. CleR, AO-S, SW, and JMB reviewed and contributed to the manuscript. RW is a practising bariatric surgeon, past-president of the British Obesity and Metabolic Surgery Society and chair of the UK National Bariatric Surgery Registry (NBSR). The sources of information used include expert knowledge of the status of bariatric surgery in the UK and detailed knowledge of the NBSR. JMB is a practising upper gastrointestinal surgeon with expertise in methodology and randomised clinical trials. She is chief investigator of the By-Band-Sleeve study. CleR is a clinical scientist interested in obesity medicine and surgery. AO-S is a lecturer in medical sociology and has extensive experience of analysing NHS rationing decisions, particularly relating to obesity surgery. SW has expertise in economic evaluation and costing methodology. RW is the guarantor.

  • Competing interests: We have read and understood BMJ policy on declaration of interests and have no relevant interests to declare.

  • Provenance and peer review: Not commissioned; externally peer reviewed.


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