Review
Controversies in bariatric surgery P. E. O’Brien Centre for Obesity Research and Education, Monash University, The Alfred Centre, 99 Commercial Road, Melbourne, 3004, Victoria, Australia Correspondence to: Professor P. E. O’Brien (e-mail: [email protected])
Background: There are many controversies related to bariatric surgery. This review explores selected
areas. Methods: A combination of randomized clinical trials (RCTs), systematic reviews and expert opinion have
been brought together to highlight areas of importance or conflict. Results and Conclusion: Metabolic surgery is an increasingly preferred term rather than bariatric or obesity surgery. Reporting should be standardized to include appropriate weight measures, valid disease measures and data on loss to follow-up. There are many putative mechanisms of effect of key bariatric procedures, but satiety and early satiation appear central. Weight loss must be durable. Long-term outcome studies (more than 10-year follow-up) show that biliopancreatic diversion is most effective, with 72 per cent excess weight loss (EWL). Roux-en-Y gastric bypass and laparoscopic adjustable gastric banding (LAGB) are equally effective, with 54 per cent EWL. There are no long-term data on vertical sleeve gastrectomy. Type II diabetes is a common and serious disease, usually associated with increased weight. Multiple RCTs have shown that bariatric surgery provides clear benefits over continuing with non-surgical therapies. The earlier the treatment, the more likely and durable will be the remission. Bariatric surgery should be available to all who are obese (body mass index over 30 kg/m2 ). LAGB, a safe, effective, reversible outpatient procedure, is the author’s preferred primary option. Paper accepted 26 November 2014 Published online in Wiley Online Library (www.bjs.co.uk). DOI: 10.1002/bjs.9760
Introduction
With only a small number of enthusiasts, bariatric surgery largely disappeared from clinical practice in the 1970s and 1980s until the development of complex laparoscopic surgical techniques during the 1990s. Over the past 20 years there has been a growth in safety associated with surgery, improved documentation of effectiveness in generating durable weight loss, and greater recognition of the benefits of weight loss on health, quality of life and survival. In parallel, the prevalence of obesity has grown and its effects on health and healthcare costs have been better measured. In a world with 500 million people suffering from obesity, an estimated 350 000 bariatric procedures will be performed during 2014. At this rate, only 0⋅07 per cent, less than one in 1000, will be treated during the next year (Fig. 1)1 ; this is an insignificant blip in terms of contribution to public health. Why is it that a treatment which addresses the most common of diseases, is reasonably safe and remarkably effective, is so poorly embraced? Perhaps individuals who look after these patients have failed to work as coherent groups © 2015 BJS Society Ltd Published by John Wiley & Sons Ltd
promoting the benefits of weight loss. Perhaps eligibility criteria set by the healthcare purchasers exclude too many patients. Perhaps the attitude that bariatric surgery should always be the last resort is wrong; it should be applied as soon as it becomes the most cost-effective option. Maybe the medical profession and society in general have instilled too deeply in obese people that it is their problem to solve, not that of others. Controversies in bariatric surgery are numerous. This review focuses on selected issues on the basis of their importance, timeliness and personal interest. Terminology and measurement of outcomes
The move to metabolic surgery Controversy starts with just what this area of practice is called and how its effects are measured: obesity, bariatric or metabolic surgery? It is time to get the name right. Obesity is not the right word. It is in part pejorative: a term of abuse or contempt. It carries society’s stigma for fat people. It just does not have the cachet of treating cancer. Surgical societies and surgical clinics are deleting obesity from their BJS
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Bariatric surgery No surgery
Impact of bariatric surgery on the global problem of obesity in 20111 . Some 0⋅07 per cent of obese patients worldwide, and 0⋅13 per cent in the USA, had a bariatric procedure
Fig. 1
names. Changing society’s attitude will take time. This needs to be done more quickly. The word ‘bariatric’ was introduced over 35 years ago. It is a reasonably correct and obscure term that provides a neutral tone. The emotion and disdain can be put aside, but somehow it doesn’t feel quite right to be hiding behind its obscurity. The term ‘metabolic surgery’ is being used increasingly. It has in fact been around for many years. In 1978, Henry Buchwald and Richard Varco2 wrote a book entitled Metabolic Surgery, which they defined as ‘the operative manipulation of a normal organ or organ system to achieve a biological result for a potential health gain’. It seems a broad definition but, apart from the surgical treatment of obesity and the diseases arising from obesity, there are very few additional claimants. It has stood the test of time. It is a positive term. Metabolic surgery is a valid descriptor of what the operations do. It better represents the depth of clinical and basic science underlying the procedures, and provides a logical link with the clinical challenges faced by medical colleagues. For this review, the term ‘bariatric’ is used, but a change to ‘metabolic’ is happening and for the better.
Describing weight loss The first aim of bariatric surgery is weight loss, although this is only the means to an end. The real endpoints are improved health, better quality of life and longer survival. It is appropriate to ask how much weight has been lost, but more important to ask whether the patients are healthier, happier and whether they live longer. The optimal expression of weight loss is still debated. The primary target of any weight loss programme is loss of © 2015 BJS Society Ltd Published by John Wiley & Sons Ltd
excess fat. Bodyweight measurement is a surrogate for this. It is simple and readily available. The medical literature, however, uses total weight lost in kilograms, percentage of total bodyweight lost, change in body mass index (BMI), percentage excess weight loss (EWL) or percentage excess BMI loss. There is little argument that kilogram weight loss and change in BMI should always be provided. The percentage total weight loss is popular in medical weight loss studies, but its value is limited by blending the loss of excess weight with the normal weight of the body, the unfavourable signal-to-noise ratio that obscures the effect. Percentage EWL focuses better on the excess fat. Excess weight is largely excess fat with a small increase in muscle mass to manage the extra burden. Calculation of percentage EWL, however, requires a value for the upper limit of normal weight. Currently, there is broad acceptance of BMI 18⋅5–25 kg/m2 as the normal weight range for Western populations. Any weight above BMI 25 kg/m2 is therefore excess weight. It is simple and clear. Criticism of the validity of percentage EWL reflects its original derivation, determined not from the weight at a BMI of 25 kg/m2 , but from a set of ideal weight charts known as the Metropolitan Life Insurance scales (MLIS); these were generated by the Metropolitan Life Insurance Company in 1943 based on the observed mortality of insured, middle-aged people from the USA and Canada. The scale underwent a minor revision in 19833 . A frame-size estimate, based on the epicondylar distance at the elbow, is included, and there are different values for men and women. The MLIS correlates poorly with the BMI scale. Depending on a patient’s age, sex and bony measurement, a range of BMI values from 20 to 27 kg/m2 can be considered ‘ideal’ under the MLIS. It is being replaced by a BMI of 25 kg/m2 defining the point above which weight is excessive. The quicker this change is complete, the better. To step around the controversy regarding percentage EWL, a new measure – percentage excess BMI loss – has been promoted by some. As the two are linked variables, and generate the same value when the weight in kilograms at a BMI of 25 kg/m2 is used to define the start of excess weight, the suggestion adds nothing but confusion. Initial weight drives all measures. The more excess weight the person has, the more kilograms and BMI units they should lose, and the more they are likely to lose. However, the change in percentage EWL is then likely to be less. That is simple arithmetic. All three measures are therefore needed. Adequate weight loss reporting of bariatric surgical outcomes should include, as a minimum, the initial weight in kilograms and BMI, the change in weight, change in BMI and percentage EWL. At any time www.bjs.co.uk
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point, the denominator, the number of patients treated who have reached that time, must be included and percentage follow-up should be considered mandatory. Weight change is just one outcome of interest. Health change, quality of life, length of life and healthcare costs are also important. A composite measure that includes all relevant outcomes would be ideal. The Bariatric Analysis Reporting and Outcome System (BAROS) sought to provide such a measure4 , but contains serious flaws and has therefore had a marginal role. No better composite has yet been proposed. With so many inter-related variables, it may just not be possible. Until then, when health outcomes are reported, the criteria for the initial diagnosis of each co-morbidity must be stated explicitly and be in accordance with accepted standards. Changes in these criteria with weight loss must be reported fully. Measures of quality of life must be properly validated. Mechanisms of weight loss in bariatric surgery
Satiety and early satiation appear common to all procedures and may be key drivers of effect. There has been extensive study of Roux-en-Y gastric bypass (RYGB). The potentially relevant mechanisms are numerous and excellent reviews are available5 . There is little evidence of either restriction or malabsorption. Most likely, satiety and early satiation are important6 . There may also be a change in the sensation of taste. Variable changes in the rate of gastric pouch emptying have been reported. Diversion of food from the proximal gut may release an as yet unidentified hormone (‘foregut hypothesis’). In association with more rapid delivery of nutrients to the distal gut, circulating levels of the gut hormones glucagon-like peptide (GLP) 1 and peptide YY (PYY) are definitely increased postprandially, and provide a mechanism for satiety induction7 and insulin secretion8 (‘hindgut hypothesis’). All options for ghrelin have been reported, from total absence, mild reduction, normal values and increased levels. Recent studies also suggest that diet-induced thermogenesis9 , increased levels of circulating bile acids10 and changes to the gut microbiome11 merit further consideration. Laparoscopic adjustable gastric banding (LAGB) is still commonly described as a restrictive procedure, yet the demonstration of the primary effect of LAGB on appetite, hunger, satiety and satiation has been present for nearly 10 years12 . Gentle compression of the gastric cardia generates a background of satiety throughout the day. With eating, oesophageal peristalsis squeezes each bolus of food across the band and generates satiation13 . These effects are most likely mediated via vagal afferents, such as the © 2015 BJS Society Ltd Published by John Wiley & Sons Ltd
intraganglionic laminar endings, embedded on the myenteric ganglia of the cardia. Each bite requires from one to six peristaltic waves, taking up to a minute, to transit the band. At 1 min after each swallow and at 1 min after completion of a meal, there should be no food or fluid above the band. Restriction that prolongs transit beyond 1 min should not occur14 . Adjusting the band excessively leads to restriction to transit, proximal pouch enlargement, symptoms of reflux and heartburn, and reduced weight loss. Optimal outcome requires small bites of good food, well chewed, at a rate of one bite per min. Total energy intake is normally approximately 1000 kcal (4186 kJ) per day15 . Understanding the mechanism defines the correct instructions for patients and their doctors. The mechanism for vertical sleeve gastrectomy (VSG) has been less studied. It appears not to be a restrictive procedure as rapid gastric emptying and rapid gut transit have been shown16 . Ghrelin levels are reduced, and GLP-1 and PYY levels show a postprandial increase17 , providing a potential basis for increased satiety as a primary mechanism. Durability of weight loss after bariatric surgery
It is not difficult to achieve substantial weight loss in the short term. Most lifestyle programmes can do it. Short-term weight loss after bariatric surgery justifies neither the costs nor the risks. The key weakness of lifestyle programmes is their lack of durability. For bariatric surgery to be worthwhile the effects must last; yet most studies deal only with short-term outcomes. Follow-up of anything less than 3 years is short term; medium term is 3–10 years, and long term is beyond 10 years. Data published up to the end of 2011 on weight loss at 10 or more years after bariatric surgery have been subjected to systematic review18 . At that time there were nine reports of RYGB, seven of LAGB, and four of biliopancreatic diversion (BPD) with or without duodenal switch. No long-term outcome data for VSG are available. Table 1 summarizes the findings. Notably, all three procedures have generated substantial long-term weight loss. BPD/duodenal switch appears to be the most effective, with 71⋅7 per cent EWL. RYGB (54⋅0 per cent EWL) and LAGB (54⋅2 per cent EWL) are identical. The results emphasize the effectiveness of all these procedures, each of which has been able to maintain more than 50 per cent EWL beyond 10 years. Bariatric surgery does work, and RYGB and LAGB appear to be about equivalent in the long-term. The durability of VSG remains to be demonstrated. www.bjs.co.uk
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RYGB No. of reports
LAGB
BPD/duodenal switch
9
7
4
No. of patients initially
3194
6369
3408
Perioperative mortality*
21 of 2102 (1⋅0)
1 of 6369 (0⋅02)
27 of 3066 (0⋅9)
Follow-up achieved (%)
64
82
83
54⋅0 (28–68)
54⋅2 (33–64)
71⋅7 (69–75)
8–38
8–60
n.r.
% EWL at ≥ 10 years† Revisional procedures (% of total followed up)
*Values in parentheses are percentages; as perioperative mortality was not reported in all studies, the denominator for mortality rates may be lower than the initial number of patients. †Values are weighted mean (range). RYGB, Roux-en-Y gastric bypass; LAGB, laparoscopic adjustable gastric banding; BPD, biliopancreatic diversion; EWL, excess weight loss; n.r., not reported. Adapted from O’Brien et al.18 .
Diabetes remission rate (%)
Table 1 Bariatric surgical procedures: systematic review of long-term outcomes
100 90 80 70 60 50 40 30 20 10 0
Cleveland, 201224 Melbourne, 200823 Rome, 201225 Minnesota, 201326
NST RYGB VSG
NST LAGB
NST RYGB BPD
NST RYGB
Diabetes remission rates in the four major randomized clinical trials comparing bariatric surgical procedures with non-surgical treatments (NST). RYGB, Roux-en-Y gastric bypass; VSG, vertical sleeve gastrectomy; LAGB, laparoscopic adjustable gastric banding; BPD, biliopancreatic diversion
Fig. 2
Bariatric surgery and diabetes
Improved biochemical control for diabetes and other metabolic disorders represents the greatest strength of bariatric surgery. The metabolic effects of weight loss following bariatric surgery have been well documented and provide clinicians with an obvious path for prevention and treatment19 – 21 . Sadly, few patients with diabetes have been offered this benefit to date. Arguments against the broad application of bariatric surgery have included safety concerns, lack of high levels of evidence, insufficient understanding of mechanisms, lack of proven durability of effect, and lack of proven reduction of the complications of diabetes in association with long-term remission. All of these arguments are losing substance as new data continue to appear. The safety of bariatric surgery has improved greatly in recent years with almost no perioperative mortality risk associated with LAGB and, in expert centres, a mortality rate of 0⋅44 per cent after RYGB22 . Compared with the mortality risk of diabetes, bariatric surgery is safe. Until recently, the lack of high levels of evidence has been a valid criticism. Numerous observational studies of bariatric surgery and diabetes have often carried major deficiencies, including poor definition of both diabetes and its remission and extensive or unreported loss to follow-up. Systematic reviews19,21 have sought to resolve these deficiencies by pooling of data, although they still do not represent high-quality evidence. There are now four high-quality randomized clinical trials (RCTs)23 – 26 on this subject. The remission rate of diabetes found in these studies is summarized in Fig. 2. Three of the studies included a RYGB arm; reported remission rates were 44 per cent at 1 year in two studies24,26 and 75 per cent at 2 years in one study25 . The remission rates were
73 per cent at 2 years for LAGB23 , 95 per cent at 2 years for BPD25 and for 37 per cent at 1 year for VSG24 . The studies contain sufficient heterogeneity to limit comparisons, but have established the significantly greater effectiveness of bariatric surgical procedures over non-surgical treatment. The durability of effect of bariatric surgery on diabetes remission and reduction of complications has been demonstrated at 15-year follow-up in the Swedish Obese Subjects (SOS) study27 , a prospective matched cohort study. The remission rate for the surgical group (predominantly gastroplasty) was 72 per cent at 2 years and 31 per cent at 15 years. Although it decreased with time, this remission rate was significantly better than that in the control group. More importantly, macrovascular and microvascular complications of diabetes were fewer at 15 years in the surgical group. The Cleveland Clinic group28 has recently reported 3-year follow-up data from an RCT. They confirmed stability of the effectiveness of RYGB but questioned the durability of VSG, following which the rate of remission from diabetes fell from 37 per cent at 1 year to 24 per cent at 3 years, representing a 50 per cent relapse rate. This failure rate was not significantly different from the 80 per cent relapse rate of the non-surgical treatment group. The duration of diabetes before bariatric surgery is a consistent and strong predictor of remission27,28 . A commitment to substantial weight loss must be a component of the early management of the obese person with diabetes. The SOS study27 reported that patients who had bariatric surgery within the first year of diagnosis of diabetes had more than twice the likelihood of remission of diabetes at 2 years and approximately six times the likelihood of remission at 15 years, compared with patients diagnosed more than 4 years before surgery. If a newly diagnosed obese
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Controversies in bariatric surgery
patient with diabetes cannot achieve substantial weight loss by lifestyle change, early referral for consideration of bariatric surgery should now be regarded as essential. Revisions and reoperations after bariatric surgery
Obesity is a chronic condition. An effective treatment must last a lifetime or recurrence of obesity is almost certain. It is unrealistic to expect that a single treatment provided today will always remain effective without additional attention. Whatever procedure is done, something may change that is best managed by surgical correction. Reoperations and revisions occur after all bariatric procedures29 – 32 . Long-term data indicate that the relative needs of stapling or banding are no different. In the systematic review18 of all procedures that reported 10 years or more of follow-up, the revision/reoperation rates were 8–38 per cent for RYGB, 8–60 per cent for LAGB and 10–40 per cent for gastroplasty (Table 1). As long as the problem leading to revision is not dangerous and correction of the problem is possible, revision should be accepted as a part of a bariatric treatment programme. LAGB requires revision for proximal gastric enlargements, erosion or access-port problems. These are best managed by replacement of the band or repair of the port. Almost all are safe, outpatient procedures and subsequent weight loss is identical to that in patients without revision18 . With repeated need for revision, or more often at the surgeon’s preference, conversion to RYGB, VSG or BPD may occur. With conversion to RYGB, it appears that the major complication rate arising from RYGB as a secondary procedure after LAGB is no different from that for a primary procedure, supporting a sequential approach to selecting bariatric surgical options33 . Patient selection
Minimum body mass index The ‘National Institutes of Health (NIH) criteria’, which many countries follow, are usually stated as BMI over 40 kg/m2 , or BMI 35–40 kg/m2 with co-morbidities. These were generated by a consensus conference convened by the NIH in the USA 22 years ago34 , at a time of open gastric stapling procedures, high surgical morbidity, mortality rates of at least 2 per cent35 , and an almost total absence of level 1 evidence of effectiveness. There has been no reassessment of these NIH criteria, yet obesity is a disease that, for the Western world, begins at a BMI of 30 kg/m2 . There is now level 1 evidence of greater weight loss and better health and quality of life after © 2015 BJS Society Ltd Published by John Wiley & Sons Ltd
bariatric surgery compared with lifestyle therapy in the mild to moderately obese (BMI 30–35 kg/m2 )36,37 . At least for patients with diabetes, this approach has a dominant level of cost-effectiveness, with bariatric surgery providing an increased number of quality-adjusted life-years at a lower cost than non-surgical therapies38 . There is increasing support for a BMI of 30 kg/m2 being the lower cut-off36,39,40 . As excess bodyweight is a dominant driver of type II diabetes, the benefit of weight loss in the overweight (BMI 25–30 kg/m2 ) is now being assessed41 – 43 . In an RCT43 of multidisciplinary diabetes care with or without LAGB, remission of diabetes at 2 years was achieved in 52 per cent of the LAGB group compared with 8 per cent in the non-LAGB group. Further study of metabolic surgery as a part of treatment for overweight people with diabetes is indicated.
Minimum age Adolescent obesity is a serious and common health challenge; there are more than five million obese adolescents in the USA alone. It is associated with a major increase in prevalence of disease and reduced life expectancy. An RCT44 comparing LAGB with an optimal medical weight loss programme in adolescents aged 14–18 years demonstrated better weight loss (79 versus 13 per cent EWL), reversal of the metabolic syndrome (from 38 per cent to zero) and improved quality of life at 2 years for the patients who had LAGB44 . Adolescence is a critical phase of educational, physical and social development. Failing to offer a proven treatment to obese adolescents compromises this development, with reduced future health and life prospects. Consideration of bariatric surgery should be available for those with severe obesity aged 14 years and above.
Choice of bariatric procedure The advice that surgeons give their patients inevitably reflects experience and training in the context of that healthcare system. The following is a personal view on the basis of extensive experience with RYGB and other stapling procedures, experience with LAGB since its introduction, research into obesity, weight loss and bariatric surgery, and experience of the healthcare systems of Australia and the USA. LAGB is the initial recommendation to nearly all patients, on the basis that it is an effective treatment that is simple, safe and preferable to more complex and riskier alternatives. In favour of LAGB, it is a relatively brief outpatient procedure that has proven effectiveness and is www.bjs.co.uk
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safe. Adjustability permits maintenance of effect as long as the band is in place. Reversibility permits access to other surgical options if needed or to therapeutic options that may be developed in the future. On the negative side, LAGB needs long-term skilled aftercare and there is a maintenance requirement, with current data indicating that up to 20 per cent may need some form of revisional procedure during the first 10 years. Approximately one-half of the revisions are required to correct a proximal gastric enlargement and one-half to correct access-port problems, a minor subcutaneous procedure. Currently less than 1 per cent of patients need revision for erosion. Revision with replacement of the band for proximal gastric enlargement or erosion is effective, and long-term weight loss after revisional surgery is equal to that among patients not needing revision18,45 . Gastric bypass is the next most favoured. RYGB has been known to be the most effective of the stomach stapling procedures since the 1980s46 . It has an established record of achieving good weight loss and health benefits, particularly in the short term. On the negative side, it creates a complex change to the normal anatomy, carries significant risk, is non-adjustable and essentially not reversible. Its effectiveness tends to fade with time. In the first 12 months after RYGB, weight loss of 60–75 per cent EWL can be expected. This effect is maintained for 12–24 months and then weight loss diminishes, so that an average of 55 per cent EWL is seen in those still attending follow-up at 5 years. It still carries a small but significant risk of death22 and for this reason alone should not be the first-line procedure. Recently, the single-anastomosis gastric bypass, otherwise referred to as the mini-gastric bypass or the omega-loop gastric bypass, has been shown to be at least as effective as RYGB47,48 . It is simpler and safer to perform. In contrast to predictions49 , it does not seem to be associated with excessive problems from bile reflux gastritis and oesophagitis50 . BPD has a small second-line role. It is the most metabolically severe of the current options and therefore has not proved popular with patients or surgeons in spite of favourable published outcomes. BPD has been available for more than 30 years51 and yet remains a minor part (less than 2 per cent) of bariatric surgery worldwide1 . It does, however, generate good weight loss and has impressive effectiveness for type II diabetes25 . It should be considered in selected patients as a second-line bariatric surgical option. VSG remains unproven. The sleeve is the first element of the duodenal switch procedure, a variant of the BPD. It has now become the most popular bariatric procedure worldwide because of the ease of the surgery, early effectiveness and perceived lack of need for close follow-up. There is © 2015 BJS Society Ltd Published by John Wiley & Sons Ltd
an expectation, however, that the sleeve will fail to maintain acceptable levels of weight loss in the medium term as the tube of residual stomach expands. Continuation to completion of the duodenal switch or other options would then need to be considered. Long-term outcome data for VSG are needed. VSG may be appropriate in countries where remoteness makes the follow-up required for LAGB difficult. The evidence base supporting bariatric (metabolic) surgery is now strong. All current procedures are safe and effective. Despite this, the adoption of minimally invasive surgery internationally is poor. The surgical community should bring greater pressure to bear on healthcare providers to address this deficiency.
Acknowledgements
The Centre for Obesity Research and Education receives research or educational support from Allergan, Applied Medical, Ramsay Healthcare and Stryker Corporation. Disclosure: The author declares no other conflict of interest. References 1 Buchwald H, Oien DM. Metabolic/bariatric surgery worldwide 2011. Obes Surg 2013; 23: 427–436. 2 Buchwald H, Varco R. Metabolic Surgery. Grune and Stratton: New York, 1978. 3 Metropolitan Life Insurance Company. 1983 metropolitan height and weight tables. Stat Bull 1983; 64: 2–9. 4 Oria HE, Moorehead MK. Bariatric analysis and reporting outcome system (BAROS). Obes Surg 1998; 8: 487–499. 5 Miras AD, le Roux CW. Mechanisms underlying weight loss after bariatric surgery. Nat Rev Gastroenterol Hepatol 2013; 10: 575–584. 6 le Roux CW, Bueter M, Theis N, Werling M, Ashrafian H, Lowenstein C et al. Gastric bypass reduces fat intake and preference. Am J Physiol Regul Integr Comp Physiol 2011; 301: R1057–R1066. 7 Pournaras DJ, Le Roux CW. The effect of bariatric surgery on gut hormones that alter appetite. Diabetes Metab 2009; 35: 508–512. 8 Cummings DE, Overduin J, Foster-Schubert KE. Gastric bypass for obesity: mechanisms of weight loss and diabetes resolution. J Clin Endocrinol Metab 2004; 89: 2608–2615. 9 Werling M, Olbers T, Fandriks L, Bueter M, Lönroth H, Stenlof K et al. Increased postprandial energy expenditure may explain superior long term weight loss after Roux-en-Y gastric bypass compared to vertical banded gastroplasty. PLoS One 2013; 8: e60280. 10 Pournaras DJ, le Roux CW. Are bile acids the new gut hormones? Lessons from weight loss surgery models. Endocrinology 2013; 154: 2255–2256.
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11 Li JV, Ashrafian H, Bueter M, Kinross J, Sands C, le Roux CW. Metabolic surgery profoundly influences gut microbial–host metabolic cross-talk. Gut 2011; 60: 1214–1223. 12 Dixon AF, Dixon JB, O’Brien PE. Laparoscopic adjustable gastric banding induces prolonged satiety: a randomized blind crossover study. J Clin Endocrinol Metab 2005; 90: 813–819. 13 Burton PR, Brown W, Laurie C, Lee M, Korin A, Anderson M et al. Outcomes, satiety, and adverse upper gastrointestinal symptoms following laparoscopic adjustable gastric banding. Obes Surg 2011; 21: 574–581. 14 Burton PR, Yap K, Brown WA, Laurie C, O’Donnell M, Hebbard G et al. Changes in satiety, supra- and infraband transit, and gastric emptying following laparoscopic adjustable gastric banding: a prospective follow-up study. Obes Surg 2011; 21: 217–223. 15 Colles SL, Dixon JB, O’Brien PE. Hunger control and regular physical activity facilitate weight loss after laparoscopic adjustable gastric banding. Obes Surg 2008; 18: 833–840. 16 Melissas J, Leventi A, Klinaki I, Perisinakis K, Koukouraki S, de Bree E et al. Alterations of global gastrointestinal motility after sleeve gastrectomy: a prospective study. Ann Surg 2013; 258: 976–982. 17 Dimitriadis E, Daskalakis M, Kampa M, Peppe A, Papadakis JA, Melissas J. Alterations in gut hormones after laparoscopic sleeve gastrectomy: a prospective clinical and laboratory investigational study. Ann Surg 2013; 257: 647–654. 18 O’Brien P, McDonald L, Anderson M, Brennan L, Brown WA. Long term outcomes after bariatric surgery: fifteen year follow up after gastric banding and a systematic review of the literature. Ann Surg 2013; 257: 87–94. 19 Buchwald H, Estok R, Fahrbach K, Banel D, Jensen MD, Pories WJ et al. Weight and type 2 diabetes after bariatric surgery: systematic review and meta-analysis. Am J Med 2009; 122: 248–256.e5. 20 Dixon JB, le Roux CW, Rubino F, Zimmet P. Bariatric surgery for type 2 diabetes. Lancet 2012; 379: 2300–2311. 21 Maggard-Gibbons M, Maglione M, Livhits M, Ewing B, Maher AR, Hu J et al. Bariatric surgery for weight loss and glycemic control in nonmorbidly obese adults with diabetes: a systematic review. JAMA 2013; 309: 2250–2261. 22 Flum DR, Belle SH, King WC, Wahed AS, Berk P, Chapman W et al. Perioperative safety in the longitudinal assessment of bariatric surgery. N Engl J Med 2009; 361: 445–454. 23 Dixon JB, O’Brien PE, Playfair J, Chapman L, Schachter LM, Skinner S et al. Adjustable gastric banding and conventional therapy for type 2 diabetes: a randomized controlled trial. JAMA 2008; 299: 316–323. 24 Schauer PR, Kashyap SR, Wolski K, Brethauer SA, Kirwan JP, Pothier CE et al. Bariatric surgery versus intensive medical therapy in obese patients with diabetes. N Engl J Med 2012; 366: 1567–1576.
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25 Mingrone G, Panunzi S, De Gaetano A, Guidone C, Iaconelli A, Leccesi L et al. Bariatric surgery versus conventional medical therapy for type 2 diabetes. N Engl J Med 2012; 366: 1577–1585. 26 Ikramuddin S, Korner J, Lee WJ, Connett JE, Inabnet WB, Billington CJ et al. Roux-en-Y gastric bypass vs intensive medical management for the control of type 2 diabetes, hypertension, and hyperlipidemia: the Diabetes Surgery Study randomized clinical trial. JAMA 2013; 309: 2240–2249. 27 Sjöström L, Peltonen M, Jacobson P, Ahlin S, Andersson-Assarsson J, Anveden Å et al. Association of bariatric surgery with long-term remission of type 2 diabetes and with microvascular and macrovascular complications. JAMA 2014; 311: 2297–2304. 28 Schauer PR, Bhatt DL, Kirwan JP, Wolski K, Brethauer SA, Navaneethan SD et al. Bariatric surgery versus intensive medical therapy for diabetes – 3-year outcomes. N Engl J Med 2014; 370: 2002–2013. 29 Himpens J, Coromina L, Verbrugghe A, Cadière GB. Outcomes of revisional procedures for insufficient weight loss or weight regain after Roux-en-Y gastric bypass. Obes Surg 2012; 22: 1746–1754. 30 Patel S, Szomstein S, Rosenthal RJ. Reasons and outcomes of reoperative bariatric surgery for failed and complicated procedures (excluding adjustable gastric banding). Obes Surg 2011; 21: 1209–1219. 31 Lee WJ, Lee YC, Ser KH, Chen SC, Chen JC, Su YH. Revisional surgery for laparoscopic minigastric bypass. Surg Obes Relat Dis 2011; 7: 486–491. 32 Morales MP, Wheeler AA, Ramaswamy A, Scott JS, de la Torre RA. Laparoscopic revisional surgery after Roux-en-Y gastric bypass and sleeve gastrectomy. Surg Obes Relat Dis 2010; 6: 485–490. 33 Thereaux J, Barsamian C, Corigliano N, Beauchet A, Poitou C, Oppert J et al. Similar postoperative safety between primary and revisional gastric bypass for failed gastric banding. JAMA Surg 2014; 149: 780–786. 34 Gastrointestinal surgery for severe obesity: National Institutes of Health Consensus Development Conference statement. Am J Clin Nutr 1992; 55: 615S–619S. 35 Flum DR, Salem L, Elrod JA, Dellinger EP, Cheadle A, Chan L. Early mortality among Medicare beneficiaries undergoing bariatric surgical procedures. JAMA 2005; 294: 1903–1908. 36 Picot J, Jones J, Coquitt JL, Loveman E, Clegg A. Weight loss surgery for mild to moderate obesity: a systematic review and economic evaluation. Obes Surg 2012; 22: 1496–1506. 37 O’Brien PE, Brennan L, Laurie C, Brown W. Intensive medical weight loss or laparoscopic adjustable gastric banding in the treatment of mild to moderate obesity: long-term follow-up of a prospective randomised trial. Obes Surg 2013; 23: 1345–1353. 38 Keating CL, Dixon JB, Moodie ML, Peeters A, Bulfone L, Maglianno DJ et al. Cost-effectiveness of surgically induced
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weight loss for the management of type 2 diabetes: modeled lifetime analysis. Diab Care 2009; 32: 567–574. ASMBS Clinical Issues Committee. Bariatric surgery in class I obesity (body mass index 30–35 kg/m2 ). Surg Obes Relat Dis 2013; 9: e1–e10. Busetto L, Dixon J, De Luca M, Shikora S, Pories W, Angrisani L. Bariatric surgery in class I obesity: Position Statement from the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO). Obes Surg 2014; 24: 487–519. De Paula AL, Stival AR, Macedo A, Ribamar J, Mancini M, Halpern A et al. Prospective randomized controlled trial comparing 2 versions of laparoscopic ileal interposition associated with sleeve gastrectomy for patients with type 2 diabetes with BMI 21–34 kg/m2 . Surg Obes Relat Dis 2010; 6: 296–304. Klein S, Fabbrini E, Patterson BW, Polonsky KS, Schiavon CA, Correa JL et al. Moderate effect of duodenal–jejunal bypass surgery on glucose homeostasis in patients with type 2 diabetes. Obesity (Silver Spring) 2012; 20: 1266–1272. Wentworth JM, Playfair J, Laurie C, Ritchie ME, Brown WA, Burton P et al. Multidisciplinary diabetes care with and without bariatric surgery in overweight people: a randomised controlled trial. Lancet Diabetes Endocrinol 2014; 2: 545–552. O’Brien PE, Sawyer SM, Laurie C, Brown WA, Skinner S, Veit F et al. Laparoscopic adjustable gastric banding in
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severely obese adolescents: a randomized trial. JAMA 2010; 303: 519–526. Brown W, Egberts KJ, Franke-Richard D, Thodiyil P, Anderson MA, O’Brien PE. Erosions after laparoscopic adjustable gastric banding: diagnosis and management. Ann Surg 2013; 257: 1047–1052. Hall JC, Watts JM, O’Brien PE, Dunstan RE, Walsh JF, Slavotinek AH et al. Gastric surgery for morbid obesity. The Adelaide Study. Ann Surg 1990; 211: 419–427. Lee WJ, Yu PJ, Wang W, Chen TC, Wei PL, Huang MT. Laparoscopic Roux-en-Y versus mini-gastric bypass for the treatment of morbid obesity: a prospective randomized controlled clinical trial. Ann Surg 2005; 242: 20–28. Lee WJ, Ser KH, Lee YC, Tsou JJ, Chen SC, Chen JC. Laparoscopic Roux-en-Y vs. mini-gastric bypass for the treatment of morbid obesity: a 10-year experience. Obes Surg 2012; 22: 1827–1834. Fisher BL, Buchwald H, Clark W, Champion JK, Fox SR, MacDonald KG et al. Mini-gastric bypass controversy. Obes Surg 2001; 11: 773–777. Mahawar KK, Jennings N, Brown J, Gupta A, Balupuri S, Small PK. ‘Mini’ gastric bypass: systematic review of a controversial procedure. Obes Surg 2013; 23: 1890–1898. Scopinaro N, Gianetta E, Civalleri D, Bonalumi U, Bachi V. Bilio-pancreatic bypass for obesity: II. Initial experience in man. Br J Surg 1979; 66: 618–620.
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Controversies in bariatric surgery P. E. O’Brien Centre for Obesity Research and Education, Monash University, The Alfred Centre, 99 Commercial Road, Melbourne, 3004, Victoria, Australia Correspondence to: Professor P. E. O’Brien (e-mail: [email protected])
Background: There are many controversies related to bariatric surgery. This review explores selected
areas. Methods: A combination of randomized clinical trials (RCTs), systematic reviews and expert opinion have
been brought together to highlight areas of importance or conflict. Results and Conclusion: Metabolic surgery is an increasingly preferred term rather than bariatric or obesity surgery. Reporting should be standardized to include appropriate weight measures, valid disease measures and data on loss to follow-up. There are many putative mechanisms of effect of key bariatric procedures, but satiety and early satiation appear central. Weight loss must be durable. Long-term outcome studies (more than 10-year follow-up) show that biliopancreatic diversion is most effective, with 72 per cent excess weight loss (EWL). Roux-en-Y gastric bypass and laparoscopic adjustable gastric banding (LAGB) are equally effective, with 54 per cent EWL. There are no long-term data on vertical sleeve gastrectomy. Type II diabetes is a common and serious disease, usually associated with increased weight. Multiple RCTs have shown that bariatric surgery provides clear benefits over continuing with non-surgical therapies. The earlier the treatment, the more likely and durable will be the remission. Bariatric surgery should be available to all who are obese (body mass index over 30 kg/m2 ). LAGB, a safe, effective, reversible outpatient procedure, is the author’s preferred primary option. Paper accepted 26 November 2014 Published online in Wiley Online Library (www.bjs.co.uk). DOI: 10.1002/bjs.9760
Introduction
With only a small number of enthusiasts, bariatric surgery largely disappeared from clinical practice in the 1970s and 1980s until the development of complex laparoscopic surgical techniques during the 1990s. Over the past 20 years there has been a growth in safety associated with surgery, improved documentation of effectiveness in generating durable weight loss, and greater recognition of the benefits of weight loss on health, quality of life and survival. In parallel, the prevalence of obesity has grown and its effects on health and healthcare costs have been better measured. In a world with 500 million people suffering from obesity, an estimated 350 000 bariatric procedures will be performed during 2014. At this rate, only 0⋅07 per cent, less than one in 1000, will be treated during the next year (Fig. 1)1 ; this is an insignificant blip in terms of contribution to public health. Why is it that a treatment which addresses the most common of diseases, is reasonably safe and remarkably effective, is so poorly embraced? Perhaps individuals who look after these patients have failed to work as coherent groups © 2015 BJS Society Ltd Published by John Wiley & Sons Ltd
promoting the benefits of weight loss. Perhaps eligibility criteria set by the healthcare purchasers exclude too many patients. Perhaps the attitude that bariatric surgery should always be the last resort is wrong; it should be applied as soon as it becomes the most cost-effective option. Maybe the medical profession and society in general have instilled too deeply in obese people that it is their problem to solve, not that of others. Controversies in bariatric surgery are numerous. This review focuses on selected issues on the basis of their importance, timeliness and personal interest. Terminology and measurement of outcomes
The move to metabolic surgery Controversy starts with just what this area of practice is called and how its effects are measured: obesity, bariatric or metabolic surgery? It is time to get the name right. Obesity is not the right word. It is in part pejorative: a term of abuse or contempt. It carries society’s stigma for fat people. It just does not have the cachet of treating cancer. Surgical societies and surgical clinics are deleting obesity from their BJS
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Impact of bariatric surgery on the global problem of obesity in 20111 . Some 0⋅07 per cent of obese patients worldwide, and 0⋅13 per cent in the USA, had a bariatric procedure
Fig. 1
names. Changing society’s attitude will take time. This needs to be done more quickly. The word ‘bariatric’ was introduced over 35 years ago. It is a reasonably correct and obscure term that provides a neutral tone. The emotion and disdain can be put aside, but somehow it doesn’t feel quite right to be hiding behind its obscurity. The term ‘metabolic surgery’ is being used increasingly. It has in fact been around for many years. In 1978, Henry Buchwald and Richard Varco2 wrote a book entitled Metabolic Surgery, which they defined as ‘the operative manipulation of a normal organ or organ system to achieve a biological result for a potential health gain’. It seems a broad definition but, apart from the surgical treatment of obesity and the diseases arising from obesity, there are very few additional claimants. It has stood the test of time. It is a positive term. Metabolic surgery is a valid descriptor of what the operations do. It better represents the depth of clinical and basic science underlying the procedures, and provides a logical link with the clinical challenges faced by medical colleagues. For this review, the term ‘bariatric’ is used, but a change to ‘metabolic’ is happening and for the better.
Describing weight loss The first aim of bariatric surgery is weight loss, although this is only the means to an end. The real endpoints are improved health, better quality of life and longer survival. It is appropriate to ask how much weight has been lost, but more important to ask whether the patients are healthier, happier and whether they live longer. The optimal expression of weight loss is still debated. The primary target of any weight loss programme is loss of © 2015 BJS Society Ltd Published by John Wiley & Sons Ltd
excess fat. Bodyweight measurement is a surrogate for this. It is simple and readily available. The medical literature, however, uses total weight lost in kilograms, percentage of total bodyweight lost, change in body mass index (BMI), percentage excess weight loss (EWL) or percentage excess BMI loss. There is little argument that kilogram weight loss and change in BMI should always be provided. The percentage total weight loss is popular in medical weight loss studies, but its value is limited by blending the loss of excess weight with the normal weight of the body, the unfavourable signal-to-noise ratio that obscures the effect. Percentage EWL focuses better on the excess fat. Excess weight is largely excess fat with a small increase in muscle mass to manage the extra burden. Calculation of percentage EWL, however, requires a value for the upper limit of normal weight. Currently, there is broad acceptance of BMI 18⋅5–25 kg/m2 as the normal weight range for Western populations. Any weight above BMI 25 kg/m2 is therefore excess weight. It is simple and clear. Criticism of the validity of percentage EWL reflects its original derivation, determined not from the weight at a BMI of 25 kg/m2 , but from a set of ideal weight charts known as the Metropolitan Life Insurance scales (MLIS); these were generated by the Metropolitan Life Insurance Company in 1943 based on the observed mortality of insured, middle-aged people from the USA and Canada. The scale underwent a minor revision in 19833 . A frame-size estimate, based on the epicondylar distance at the elbow, is included, and there are different values for men and women. The MLIS correlates poorly with the BMI scale. Depending on a patient’s age, sex and bony measurement, a range of BMI values from 20 to 27 kg/m2 can be considered ‘ideal’ under the MLIS. It is being replaced by a BMI of 25 kg/m2 defining the point above which weight is excessive. The quicker this change is complete, the better. To step around the controversy regarding percentage EWL, a new measure – percentage excess BMI loss – has been promoted by some. As the two are linked variables, and generate the same value when the weight in kilograms at a BMI of 25 kg/m2 is used to define the start of excess weight, the suggestion adds nothing but confusion. Initial weight drives all measures. The more excess weight the person has, the more kilograms and BMI units they should lose, and the more they are likely to lose. However, the change in percentage EWL is then likely to be less. That is simple arithmetic. All three measures are therefore needed. Adequate weight loss reporting of bariatric surgical outcomes should include, as a minimum, the initial weight in kilograms and BMI, the change in weight, change in BMI and percentage EWL. At any time www.bjs.co.uk
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point, the denominator, the number of patients treated who have reached that time, must be included and percentage follow-up should be considered mandatory. Weight change is just one outcome of interest. Health change, quality of life, length of life and healthcare costs are also important. A composite measure that includes all relevant outcomes would be ideal. The Bariatric Analysis Reporting and Outcome System (BAROS) sought to provide such a measure4 , but contains serious flaws and has therefore had a marginal role. No better composite has yet been proposed. With so many inter-related variables, it may just not be possible. Until then, when health outcomes are reported, the criteria for the initial diagnosis of each co-morbidity must be stated explicitly and be in accordance with accepted standards. Changes in these criteria with weight loss must be reported fully. Measures of quality of life must be properly validated. Mechanisms of weight loss in bariatric surgery
Satiety and early satiation appear common to all procedures and may be key drivers of effect. There has been extensive study of Roux-en-Y gastric bypass (RYGB). The potentially relevant mechanisms are numerous and excellent reviews are available5 . There is little evidence of either restriction or malabsorption. Most likely, satiety and early satiation are important6 . There may also be a change in the sensation of taste. Variable changes in the rate of gastric pouch emptying have been reported. Diversion of food from the proximal gut may release an as yet unidentified hormone (‘foregut hypothesis’). In association with more rapid delivery of nutrients to the distal gut, circulating levels of the gut hormones glucagon-like peptide (GLP) 1 and peptide YY (PYY) are definitely increased postprandially, and provide a mechanism for satiety induction7 and insulin secretion8 (‘hindgut hypothesis’). All options for ghrelin have been reported, from total absence, mild reduction, normal values and increased levels. Recent studies also suggest that diet-induced thermogenesis9 , increased levels of circulating bile acids10 and changes to the gut microbiome11 merit further consideration. Laparoscopic adjustable gastric banding (LAGB) is still commonly described as a restrictive procedure, yet the demonstration of the primary effect of LAGB on appetite, hunger, satiety and satiation has been present for nearly 10 years12 . Gentle compression of the gastric cardia generates a background of satiety throughout the day. With eating, oesophageal peristalsis squeezes each bolus of food across the band and generates satiation13 . These effects are most likely mediated via vagal afferents, such as the © 2015 BJS Society Ltd Published by John Wiley & Sons Ltd
intraganglionic laminar endings, embedded on the myenteric ganglia of the cardia. Each bite requires from one to six peristaltic waves, taking up to a minute, to transit the band. At 1 min after each swallow and at 1 min after completion of a meal, there should be no food or fluid above the band. Restriction that prolongs transit beyond 1 min should not occur14 . Adjusting the band excessively leads to restriction to transit, proximal pouch enlargement, symptoms of reflux and heartburn, and reduced weight loss. Optimal outcome requires small bites of good food, well chewed, at a rate of one bite per min. Total energy intake is normally approximately 1000 kcal (4186 kJ) per day15 . Understanding the mechanism defines the correct instructions for patients and their doctors. The mechanism for vertical sleeve gastrectomy (VSG) has been less studied. It appears not to be a restrictive procedure as rapid gastric emptying and rapid gut transit have been shown16 . Ghrelin levels are reduced, and GLP-1 and PYY levels show a postprandial increase17 , providing a potential basis for increased satiety as a primary mechanism. Durability of weight loss after bariatric surgery
It is not difficult to achieve substantial weight loss in the short term. Most lifestyle programmes can do it. Short-term weight loss after bariatric surgery justifies neither the costs nor the risks. The key weakness of lifestyle programmes is their lack of durability. For bariatric surgery to be worthwhile the effects must last; yet most studies deal only with short-term outcomes. Follow-up of anything less than 3 years is short term; medium term is 3–10 years, and long term is beyond 10 years. Data published up to the end of 2011 on weight loss at 10 or more years after bariatric surgery have been subjected to systematic review18 . At that time there were nine reports of RYGB, seven of LAGB, and four of biliopancreatic diversion (BPD) with or without duodenal switch. No long-term outcome data for VSG are available. Table 1 summarizes the findings. Notably, all three procedures have generated substantial long-term weight loss. BPD/duodenal switch appears to be the most effective, with 71⋅7 per cent EWL. RYGB (54⋅0 per cent EWL) and LAGB (54⋅2 per cent EWL) are identical. The results emphasize the effectiveness of all these procedures, each of which has been able to maintain more than 50 per cent EWL beyond 10 years. Bariatric surgery does work, and RYGB and LAGB appear to be about equivalent in the long-term. The durability of VSG remains to be demonstrated. www.bjs.co.uk
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LAGB
BPD/duodenal switch
9
7
4
No. of patients initially
3194
6369
3408
Perioperative mortality*
21 of 2102 (1⋅0)
1 of 6369 (0⋅02)
27 of 3066 (0⋅9)
Follow-up achieved (%)
64
82
83
54⋅0 (28–68)
54⋅2 (33–64)
71⋅7 (69–75)
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8–60
n.r.
% EWL at ≥ 10 years† Revisional procedures (% of total followed up)
*Values in parentheses are percentages; as perioperative mortality was not reported in all studies, the denominator for mortality rates may be lower than the initial number of patients. †Values are weighted mean (range). RYGB, Roux-en-Y gastric bypass; LAGB, laparoscopic adjustable gastric banding; BPD, biliopancreatic diversion; EWL, excess weight loss; n.r., not reported. Adapted from O’Brien et al.18 .
Diabetes remission rate (%)
Table 1 Bariatric surgical procedures: systematic review of long-term outcomes
100 90 80 70 60 50 40 30 20 10 0
Cleveland, 201224 Melbourne, 200823 Rome, 201225 Minnesota, 201326
NST RYGB VSG
NST LAGB
NST RYGB BPD
NST RYGB
Diabetes remission rates in the four major randomized clinical trials comparing bariatric surgical procedures with non-surgical treatments (NST). RYGB, Roux-en-Y gastric bypass; VSG, vertical sleeve gastrectomy; LAGB, laparoscopic adjustable gastric banding; BPD, biliopancreatic diversion
Fig. 2
Bariatric surgery and diabetes
Improved biochemical control for diabetes and other metabolic disorders represents the greatest strength of bariatric surgery. The metabolic effects of weight loss following bariatric surgery have been well documented and provide clinicians with an obvious path for prevention and treatment19 – 21 . Sadly, few patients with diabetes have been offered this benefit to date. Arguments against the broad application of bariatric surgery have included safety concerns, lack of high levels of evidence, insufficient understanding of mechanisms, lack of proven durability of effect, and lack of proven reduction of the complications of diabetes in association with long-term remission. All of these arguments are losing substance as new data continue to appear. The safety of bariatric surgery has improved greatly in recent years with almost no perioperative mortality risk associated with LAGB and, in expert centres, a mortality rate of 0⋅44 per cent after RYGB22 . Compared with the mortality risk of diabetes, bariatric surgery is safe. Until recently, the lack of high levels of evidence has been a valid criticism. Numerous observational studies of bariatric surgery and diabetes have often carried major deficiencies, including poor definition of both diabetes and its remission and extensive or unreported loss to follow-up. Systematic reviews19,21 have sought to resolve these deficiencies by pooling of data, although they still do not represent high-quality evidence. There are now four high-quality randomized clinical trials (RCTs)23 – 26 on this subject. The remission rate of diabetes found in these studies is summarized in Fig. 2. Three of the studies included a RYGB arm; reported remission rates were 44 per cent at 1 year in two studies24,26 and 75 per cent at 2 years in one study25 . The remission rates were
73 per cent at 2 years for LAGB23 , 95 per cent at 2 years for BPD25 and for 37 per cent at 1 year for VSG24 . The studies contain sufficient heterogeneity to limit comparisons, but have established the significantly greater effectiveness of bariatric surgical procedures over non-surgical treatment. The durability of effect of bariatric surgery on diabetes remission and reduction of complications has been demonstrated at 15-year follow-up in the Swedish Obese Subjects (SOS) study27 , a prospective matched cohort study. The remission rate for the surgical group (predominantly gastroplasty) was 72 per cent at 2 years and 31 per cent at 15 years. Although it decreased with time, this remission rate was significantly better than that in the control group. More importantly, macrovascular and microvascular complications of diabetes were fewer at 15 years in the surgical group. The Cleveland Clinic group28 has recently reported 3-year follow-up data from an RCT. They confirmed stability of the effectiveness of RYGB but questioned the durability of VSG, following which the rate of remission from diabetes fell from 37 per cent at 1 year to 24 per cent at 3 years, representing a 50 per cent relapse rate. This failure rate was not significantly different from the 80 per cent relapse rate of the non-surgical treatment group. The duration of diabetes before bariatric surgery is a consistent and strong predictor of remission27,28 . A commitment to substantial weight loss must be a component of the early management of the obese person with diabetes. The SOS study27 reported that patients who had bariatric surgery within the first year of diagnosis of diabetes had more than twice the likelihood of remission of diabetes at 2 years and approximately six times the likelihood of remission at 15 years, compared with patients diagnosed more than 4 years before surgery. If a newly diagnosed obese
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patient with diabetes cannot achieve substantial weight loss by lifestyle change, early referral for consideration of bariatric surgery should now be regarded as essential. Revisions and reoperations after bariatric surgery
Obesity is a chronic condition. An effective treatment must last a lifetime or recurrence of obesity is almost certain. It is unrealistic to expect that a single treatment provided today will always remain effective without additional attention. Whatever procedure is done, something may change that is best managed by surgical correction. Reoperations and revisions occur after all bariatric procedures29 – 32 . Long-term data indicate that the relative needs of stapling or banding are no different. In the systematic review18 of all procedures that reported 10 years or more of follow-up, the revision/reoperation rates were 8–38 per cent for RYGB, 8–60 per cent for LAGB and 10–40 per cent for gastroplasty (Table 1). As long as the problem leading to revision is not dangerous and correction of the problem is possible, revision should be accepted as a part of a bariatric treatment programme. LAGB requires revision for proximal gastric enlargements, erosion or access-port problems. These are best managed by replacement of the band or repair of the port. Almost all are safe, outpatient procedures and subsequent weight loss is identical to that in patients without revision18 . With repeated need for revision, or more often at the surgeon’s preference, conversion to RYGB, VSG or BPD may occur. With conversion to RYGB, it appears that the major complication rate arising from RYGB as a secondary procedure after LAGB is no different from that for a primary procedure, supporting a sequential approach to selecting bariatric surgical options33 . Patient selection
Minimum body mass index The ‘National Institutes of Health (NIH) criteria’, which many countries follow, are usually stated as BMI over 40 kg/m2 , or BMI 35–40 kg/m2 with co-morbidities. These were generated by a consensus conference convened by the NIH in the USA 22 years ago34 , at a time of open gastric stapling procedures, high surgical morbidity, mortality rates of at least 2 per cent35 , and an almost total absence of level 1 evidence of effectiveness. There has been no reassessment of these NIH criteria, yet obesity is a disease that, for the Western world, begins at a BMI of 30 kg/m2 . There is now level 1 evidence of greater weight loss and better health and quality of life after © 2015 BJS Society Ltd Published by John Wiley & Sons Ltd
bariatric surgery compared with lifestyle therapy in the mild to moderately obese (BMI 30–35 kg/m2 )36,37 . At least for patients with diabetes, this approach has a dominant level of cost-effectiveness, with bariatric surgery providing an increased number of quality-adjusted life-years at a lower cost than non-surgical therapies38 . There is increasing support for a BMI of 30 kg/m2 being the lower cut-off36,39,40 . As excess bodyweight is a dominant driver of type II diabetes, the benefit of weight loss in the overweight (BMI 25–30 kg/m2 ) is now being assessed41 – 43 . In an RCT43 of multidisciplinary diabetes care with or without LAGB, remission of diabetes at 2 years was achieved in 52 per cent of the LAGB group compared with 8 per cent in the non-LAGB group. Further study of metabolic surgery as a part of treatment for overweight people with diabetes is indicated.
Minimum age Adolescent obesity is a serious and common health challenge; there are more than five million obese adolescents in the USA alone. It is associated with a major increase in prevalence of disease and reduced life expectancy. An RCT44 comparing LAGB with an optimal medical weight loss programme in adolescents aged 14–18 years demonstrated better weight loss (79 versus 13 per cent EWL), reversal of the metabolic syndrome (from 38 per cent to zero) and improved quality of life at 2 years for the patients who had LAGB44 . Adolescence is a critical phase of educational, physical and social development. Failing to offer a proven treatment to obese adolescents compromises this development, with reduced future health and life prospects. Consideration of bariatric surgery should be available for those with severe obesity aged 14 years and above.
Choice of bariatric procedure The advice that surgeons give their patients inevitably reflects experience and training in the context of that healthcare system. The following is a personal view on the basis of extensive experience with RYGB and other stapling procedures, experience with LAGB since its introduction, research into obesity, weight loss and bariatric surgery, and experience of the healthcare systems of Australia and the USA. LAGB is the initial recommendation to nearly all patients, on the basis that it is an effective treatment that is simple, safe and preferable to more complex and riskier alternatives. In favour of LAGB, it is a relatively brief outpatient procedure that has proven effectiveness and is www.bjs.co.uk
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safe. Adjustability permits maintenance of effect as long as the band is in place. Reversibility permits access to other surgical options if needed or to therapeutic options that may be developed in the future. On the negative side, LAGB needs long-term skilled aftercare and there is a maintenance requirement, with current data indicating that up to 20 per cent may need some form of revisional procedure during the first 10 years. Approximately one-half of the revisions are required to correct a proximal gastric enlargement and one-half to correct access-port problems, a minor subcutaneous procedure. Currently less than 1 per cent of patients need revision for erosion. Revision with replacement of the band for proximal gastric enlargement or erosion is effective, and long-term weight loss after revisional surgery is equal to that among patients not needing revision18,45 . Gastric bypass is the next most favoured. RYGB has been known to be the most effective of the stomach stapling procedures since the 1980s46 . It has an established record of achieving good weight loss and health benefits, particularly in the short term. On the negative side, it creates a complex change to the normal anatomy, carries significant risk, is non-adjustable and essentially not reversible. Its effectiveness tends to fade with time. In the first 12 months after RYGB, weight loss of 60–75 per cent EWL can be expected. This effect is maintained for 12–24 months and then weight loss diminishes, so that an average of 55 per cent EWL is seen in those still attending follow-up at 5 years. It still carries a small but significant risk of death22 and for this reason alone should not be the first-line procedure. Recently, the single-anastomosis gastric bypass, otherwise referred to as the mini-gastric bypass or the omega-loop gastric bypass, has been shown to be at least as effective as RYGB47,48 . It is simpler and safer to perform. In contrast to predictions49 , it does not seem to be associated with excessive problems from bile reflux gastritis and oesophagitis50 . BPD has a small second-line role. It is the most metabolically severe of the current options and therefore has not proved popular with patients or surgeons in spite of favourable published outcomes. BPD has been available for more than 30 years51 and yet remains a minor part (less than 2 per cent) of bariatric surgery worldwide1 . It does, however, generate good weight loss and has impressive effectiveness for type II diabetes25 . It should be considered in selected patients as a second-line bariatric surgical option. VSG remains unproven. The sleeve is the first element of the duodenal switch procedure, a variant of the BPD. It has now become the most popular bariatric procedure worldwide because of the ease of the surgery, early effectiveness and perceived lack of need for close follow-up. There is © 2015 BJS Society Ltd Published by John Wiley & Sons Ltd
an expectation, however, that the sleeve will fail to maintain acceptable levels of weight loss in the medium term as the tube of residual stomach expands. Continuation to completion of the duodenal switch or other options would then need to be considered. Long-term outcome data for VSG are needed. VSG may be appropriate in countries where remoteness makes the follow-up required for LAGB difficult. The evidence base supporting bariatric (metabolic) surgery is now strong. All current procedures are safe and effective. Despite this, the adoption of minimally invasive surgery internationally is poor. The surgical community should bring greater pressure to bear on healthcare providers to address this deficiency.
Acknowledgements
The Centre for Obesity Research and Education receives research or educational support from Allergan, Applied Medical, Ramsay Healthcare and Stryker Corporation. Disclosure: The author declares no other conflict of interest. References 1 Buchwald H, Oien DM. Metabolic/bariatric surgery worldwide 2011. Obes Surg 2013; 23: 427–436. 2 Buchwald H, Varco R. Metabolic Surgery. Grune and Stratton: New York, 1978. 3 Metropolitan Life Insurance Company. 1983 metropolitan height and weight tables. Stat Bull 1983; 64: 2–9. 4 Oria HE, Moorehead MK. Bariatric analysis and reporting outcome system (BAROS). Obes Surg 1998; 8: 487–499. 5 Miras AD, le Roux CW. Mechanisms underlying weight loss after bariatric surgery. Nat Rev Gastroenterol Hepatol 2013; 10: 575–584. 6 le Roux CW, Bueter M, Theis N, Werling M, Ashrafian H, Lowenstein C et al. Gastric bypass reduces fat intake and preference. Am J Physiol Regul Integr Comp Physiol 2011; 301: R1057–R1066. 7 Pournaras DJ, Le Roux CW. The effect of bariatric surgery on gut hormones that alter appetite. Diabetes Metab 2009; 35: 508–512. 8 Cummings DE, Overduin J, Foster-Schubert KE. Gastric bypass for obesity: mechanisms of weight loss and diabetes resolution. J Clin Endocrinol Metab 2004; 89: 2608–2615. 9 Werling M, Olbers T, Fandriks L, Bueter M, Lönroth H, Stenlof K et al. Increased postprandial energy expenditure may explain superior long term weight loss after Roux-en-Y gastric bypass compared to vertical banded gastroplasty. PLoS One 2013; 8: e60280. 10 Pournaras DJ, le Roux CW. Are bile acids the new gut hormones? Lessons from weight loss surgery models. Endocrinology 2013; 154: 2255–2256.
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