Bariatric surgery in class I obesity (body mass index 30–35 kg/m2)

Abstract

The following position statement is issued by the American Society for Metabolic and Bariatric Surgery in response to numerous inquires made to the society by patients, physicians, society members, hospitals, and others regarding the safety profile and efficacy of bariatric surgery for patients with class I obesity. In this statement, available data are summarized, and recommendations for treatment are made regarding bariatric surgery for patients with a body mass index (BMI) of 30–35 kg/m2 based on current knowledge, expert opinion, and published peer-reviewed scientific evidence available at this time. The statement is not intended as, and should not be construed as, stating or establishing a local, regional, or national standard of care. The statement may be revised in the future as additional evidence becomes available. Obesity is the major epidemic of our generation. The National Health and Nutritional Examination Survey (NHANES) suggests that obesity affects women (35.8%), men (35.5%), and children (2–19 years of age, 16.9%) [1Ogden C.L. Carroll M.D. Kit B.K. Flegal K.M. Prevalence of obesity and trends in body mass index among US children and adolescents, 1999–2010.JAMA. 2012; 307: 483-490Crossref PubMed Scopus (2960) Google Scholar, 2Flegal K.M. Carroll M.D. Kit B.K. Ogden C.L. Prevalence of obesity and trends in the distribution of body mass index among US adults, 1999–2010.JAMA. 2012; 307: 491-497Crossref PubMed Scopus (4041) Google Scholar]. Increasingly, data are accumulating that many of the metabolic problems that accompany obesity begin at a BMI of 30 or even earlier and increase early mortality [3Guh D.P. Zhang W. Bansback N. Amarsi Z. Birmingham C.L. Anis A.H. The incidence of co-morbidities related to obesity and overweight: a systematic review and meta-analysis.BMC Public Health. 2009; 9: 88Crossref PubMed Scopus (2237) Google Scholar, 4Prospective Studies Collaboration. Body-mass index and cause-specific mortality in 900000 adults: collaborative analyses of 57 prospective studies. Lancet 2009;373:1083–1096.Google Scholar]. Recently, the Food and Drug Administration voted to extend the use of a medical device, the LapBand, to people afflicted with class I obesity with≥1 co-morbidities, and randomized prospective data from the STAMPEDE trial found the Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy in patients with a BMI of≥27 kg/m2 to be effective in the treatment of type 2 diabetes [[5]Schauer P.R. Kashyap S.R. Wolski K. et al.Bariatric surgery versus intensive medical therapy in obese patients with diabetes.N Engl J Med. 2012; 26: 1567-1576Crossref Scopus (1595) Google Scholar]. The current data support lowering the arbitrary BMI cutoff of 35 kg/m2 established in 1991 by offering surgical therapy to patients with class I obesity. The primary purpose of this review is to evaluate the evidence regarding the benefits and risks of all bariatric procedures in patients with BMI>30 kg/m2. Class I obesity as a health problem. Obesity is defined as a disease in which fat has accumulated to the extent that health is impaired. In the absence of a simple direct method for measuring total body fat, the BMI is the most common method for describing levels of obesity. For Western societies, the World Health Organization and the U.S. National Institutes of Health (NIH) have defined BMI>30 kg/m2 as being obese [6Obesity: preventing and managing the global epidemic. Report of a WHO consultation. World Health Organ Tech Rep Ser 2000;894:1–253.Google Scholar, 7Clinical guidelines on the identification, evaluation and treatment of overweight and obesity in adults—the evidence report. National Institutes of Health. Obes Res 1998;6:51S–209S.Google Scholar], primarily on the basis of associated mortality risk. In addition, the co-morbid conditions associated with obesity contributed substantially to the definition. Overweight and obesity can be divided into 4 levels of severity of co-morbidity and mortality risk (Table 1).Table 1Classification of obesityClassificationBMI rangeHealth and survival riskOverweight25–30MildClass I30–35ModerateClass II35–40SevereClass III>40Very severeBMI = body mass index. Open table in a new tab BMI = body mass index. The morbidity and mortality risks of obesity have been subject to multiple systematic reviews. Some of these provide a global overview [[8]Haslam D.W. James W.P. Obesity.Lancet. 2005; 366: 1197-1209Abstract Full Text Full Text PDF PubMed Scopus (3422) Google Scholar], but others are focused on specific weight-related diseases such as diabetes [[9]Hartemink N. Boshuizen H.C. Nagelkerke N.J. Jacobs M.A. van Houwelingen H.C. Combining risk estimates from observational studies with different exposure cutpoints: a meta-analysis on body mass index and diabetes type 2.Am J Epidemiol. 2006; 163: 1042-1052Crossref PubMed Scopus (151) Google Scholar], cardiovascular disease [[10]Ni Mhurchu C. Rodgers A. Pan W.H. Gu D.F. Woodward M. Asia Pacific Cohort Studies Collaboration. Body mass index and cardiovascular disease in the Asia-Pacific Region: an overview of 33 cohorts involving 310000 participants.Int J Epidemiol. 2004; 33: 751-758Crossref PubMed Scopus (273) Google Scholar], and various cancers [11Bergstrom A. Pisani P. Tenet V. Wolk A. Adami H.O. Overweight as an avoidable cause of cancer in Europe.Int J Cancer. 2001; 91: 421-430Crossref PubMed Scopus (658) Google Scholar, 12Harvie M. Hooper L. Howell A.H. Central obesity and breast cancer risk: a systematic review.Obes Rev. 2003; 4: 157-173Crossref PubMed Scopus (303) Google Scholar, 13Kubo A. Corley D.A. Body mass index and adenocarcinomas of the esophagus or gastric cardia: a systematic review and meta-analysis.Cancer Epidemiol Biomarkers Prev. 2006; 15: 872-878Crossref PubMed Scopus (332) Google Scholar, 14Berrington de Gonzalez A. Sweetland S. Spencer E. A meta-analysis of obesity and the risk of pancreatic cancer.Br J Cancer. 2003; 89: 519-523Crossref PubMed Scopus (267) Google Scholar, 15MacInnis R.J. English D.R. Body size and composition and prostate cancer risk: systematic review and meta-regression analysis.Cancer Causes Control. 2006; 17: 989-1003Crossref PubMed Scopus (276) Google Scholar]. A recent comprehensive systematic review and meta-analysis of the possible co-morbidity risks for both overweight and the classes of obesity has brought together the data from 89 individual studies [[3]Guh D.P. Zhang W. Bansback N. Amarsi Z. Birmingham C.L. Anis A.H. The incidence of co-morbidities related to obesity and overweight: a systematic review and meta-analysis.BMC Public Health. 2009; 9: 88Crossref PubMed Scopus (2237) Google Scholar], and the pooled relative risk for co-morbidities related to the severity of obesity was calculated. Significant associations were found between all classes of overweight/obesity and type 2 diabetes, coronary artery disease, hypertension, congestive heart failure, asthma, stroke, pulmonary embolism, gallbladder disease, 9 common cancers, osteoarthritis, and chronic back pain. Although class I obesity was not identified separately from overweight or the more severely obese, the findings were present for both the overweight and all 3 classes of obesity, confirming the effect of class I obesity in the pathogenesis of these diseases. The mortality risk of obesity is best examined by following large populations over many years. The Prospective Studies Collaboration is an international consortium of 61 large, prospective epidemiologic studies mainly from North America and Europe and based at the University of Oxford. They analyzed 57 of these studies involving nearly 900,000 adults for whom BMI was available [[4]Prospective Studies Collaboration. Body-mass index and cause-specific mortality in 900000 adults: collaborative analyses of 57 prospective studies. Lancet 2009;373:1083–1096.Google Scholar]. They excluded the data from the first 5 years of follow-up and tracked outcomes for a mean of 8 years. They related BMI to cause-specific mortality and reported that, from a BMI of 25 kg/m2, mortality was approximately 30% greater for each additional 5 kg/m2. The risk status was largely independent of age. Also noted was an increased risk of stroke, myocardial infarction, and diabetes. Overall, for class I obesity, the life span was decreased by 3 years. Similar findings had been derived from the Framingham database [[16]Himpens J, Dobbeleir J, Peeters G. Long-term results of laparoscopic sleeve gastrectomy for obesity. Ann Surg 252:319–24.Google Scholar] and the NHANES [[17]Fontaine K.R. Redden D.T. Wang C. Westfall A.O. Allison D.B. Years of life lost due to obesity.JAMA. 2003; 289: 187-193Crossref PubMed Scopus (1778) Google Scholar]. In a Special Report in the New England Journal of Medicine [[18]Olshansky S.J. Passaro D.J. Hershow R.C. et al.A potential decline in life expectancy in the United States in the 21st century.N Engl J Med. 2005; 352: 1138-1145Crossref PubMed Scopus (1971) Google Scholar], Olshansky et al. argued that the increasing problems of obesity and its co-morbidities, particularly type 2 diabetes, will override the benefits of other health advances and a continued increase in life expectancy will not persist. From these data, we conclude that class I obesity is a health problem that leads to additional serious co-morbidities and a shortened life expectancy. Therefore, class I obesity deserves effective treatment. Historic perspective for treatment recommendations. The morbidity and mortality caused by the disease of obesity is well established and has long been recognized by all major advisory bodies. It was recognized by an NIH consensus conference in 1985. A subsequent separate consensus conference, held in March 1991, considered the role of bariatric surgery for these patients [[19]Gastrointestinal surgery for severe obesity: National Institutes of Health Consensus Development Conference statement. Am J Clin Nutr 1992;55:615S–619SS.Google Scholar]. A synthesis of the views of the opinion leaders present at that time recommended that bariatric surgery should be considered for those patients who have BMI>40, BMI>35 in association with major co-morbidities such as severe sleep apnea, Pickwickian syndrome, obesity-related cardiomyopathy, or BMI>35 in association with obesity-induced physical problems with lifestyle, including joint disease or body size problems interfering with employment, family function, and ambulation. Since the NIH consensus conference, new procedures have been introduced, the laparoscopic approach has largely replaced open surgery, and higher levels of scientific evidence are now available regarding the health hazards of obesity and the risks and benefits of bariatric surgery. Given the major changes that have occurred in this field, it is appropriate to review the data now available, and in the context of bariatric surgery as it is currently practiced, consider modification of the arbitrary recommendations established 20 years ago. Despite attempts to update the recommendations of the original guidelines [20DeMaria E.J. Schauer P. Patterson E. et al.The optimal surgical management of the super-obese patient: the debate.Surg Innov. 2005; 12: 107-121Crossref PubMed Scopus (47) Google Scholar, 21Sugerman H.J. Summary: Consensus conference on surgery for severe obesity.Surg Obes Relat Dis. 2005; 1: 369-370Abstract Full Text Full Text PDF Scopus (6) Google Scholar], private health insurers and Medicare continue to rely on the 1991 consensus conference guidelines to set a baseline for BMI above which bariatric surgery offers a favorable risk/benefit ratio. The correct placement of that baseline is of critical importance to the patient, the doctor, and the payor. In particular, the time has come to address the appropriate place for bariatric surgery for the treatment of patients with class I obesity. This discussion should consider whether class I obesity is a clinically relevant health problem, whether it is adequately managed by nonsurgical means, and whether there is evidence that bariatric surgical techniques provide a well-tolerated and cost-effective treatment approach. Nonsurgical treatment of class I obesity. In the treatment algorithm for class I obesity, the most well-tolerated treatment that is effective should be the preferred option. All individuals seeking weight loss should begin with nonsurgical therapy and consider bariatric surgery only if they are unable to achieve sufficient long-term weight loss and co-morbidity improvement with nonsurgical therapies. For most people with class I obesity, however, it is clear that the nonsurgical group of therapies will not provide a durable solution to their disease of obesity. Most will not lose a substantial amount of weight with these measures, and most who do lose weight will regain the weight within 1–2 years. Systematic reviews of the numerous randomized controlled trials (RCTs) of programs incorporating diets, exercise, pharmacotherapy, and behavioral therapy have reported a mean weight loss in the range of 2–6 kg at 1 year or less [22Avenell A. Brown T.J. McGee M.A. et al.What are the long-term benefits of weight reducing diets in adults? A systematic review of randomized controlled trials.J Hum Nutr Diet. 2004; 17: 317-335Crossref PubMed Scopus (128) Google Scholar, 23Avenell A. Brown T.J. McGee M.A. et al.What interventions should we add to weight reducing diets in adults with obesity? A systematic review of randomized controlled trials of adding drug therapy, exercise, behaviour therapy or combinations of these interventions.J Hum Nutr Diet. 2004; 17: 293-316Crossref PubMed Scopus (132) Google Scholar, 24Bravata D.M. Sanders L. Huang J. et al.Efficacy and safety of low-carbohydrate diets: a systematic review.JAMA. 2003; 289: 1837-1850Crossref PubMed Scopus (475) Google Scholar, 25Dansinger M.L. Gleason J.A. Griffith J.L. Selker H.P. Schaefer E.J. Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets for weight loss and heart disease risk reduction: a randomized trial.JAMA. 2005; 293: 43-53Crossref PubMed Scopus (1273) Google Scholar, 26Padwal R. Li S.K. Lau D.C. Long-term pharmacotherapy for overweight and obesity: a systematic review and meta-analysis of randomized controlled trials.Int J Obes Relat Metab Disord. 2003; 27: 1437-1446Crossref PubMed Scopus (267) Google Scholar] with poor maintenance of that weight loss beyond that time [[27]Svetkey L.P. Stevens V.J. Brantley P.J. et al.Comparison of strategies for sustaining weight loss: the weight loss maintenance randomized controlled trial.JAMA. 2008; 299: 1139-1148Crossref PubMed Scopus (556) Google Scholar]. However, within the total group of participants studied in these trials and within the general practice of bariatric medicine, there are individuals who have achieved substantial and durable weight loss and have been able to maintain that weight loss for several years. Therefore, before considering surgical treatment for obesity for any individual, an adequate trial of nonsurgical therapy should always be required. If, however, the attempts at treating their obesity and obesity-related co-morbidities have not been effective, we must recognize that the individual has a problem that threatens their health and life expectancy, and we must seek an effective, durable therapy such as bariatric surgery. Bariatric surgery for class I obesity. There is a robust body of literature to support the safety profile and efficacy of bariatric surgery in patients who meet current NIH criteria. Many of the published articles demonstrate clear weight loss and co-morbidity benefits for patients who are at the low end of the currently accepted criteria. Although the data for patients with BMI 35–40 kg/m2 who have undergone bariatric surgery cannot be directly extrapolated to the 30–35 population, it is reasonable to expect the same beneficial effects of the surgery in this lower BMI group. Further data in the lower BMI group have been needed to better define the risk/benefit ratio for this patient population. To date, there are 4 RCTs that include patients with BMI 30–35 kg/m2 [5Schauer P.R. Kashyap S.R. Wolski K. et al.Bariatric surgery versus intensive medical therapy in obese patients with diabetes.N Engl J Med. 2012; 26: 1567-1576Crossref Scopus (1595) Google Scholar, 28Dixon J.B. O'Brien P.E. Playfair J. et al.Adjustable gastric banding and conventional therapy for type 2 diabetes: a randomized controlled trial.JAMA. 2008; 299: 316-323Crossref PubMed Scopus (1143) Google Scholar, 29Lee W.J. Chong K. Ser K.H. et al.Gastric bypass vs sleeve gastrectomy for type 2 diabetes mellitus: a randomized controlled trial.Arch Surg. 2011; 146: 143-148Crossref PubMed Scopus (347) Google Scholar, 30O'Brien P.E. Dixon J.B. Laurie C. et al.Treatment of mild to moderate obesity with laparoscopic adjustable gastric banding or an intensive medical program: a randomized trial.Ann Intern Med. 2006; 144: 625-633Crossref PubMed Scopus (412) Google Scholar]. Three of these trials [5Schauer P.R. Kashyap S.R. Wolski K. et al.Bariatric surgery versus intensive medical therapy in obese patients with diabetes.N Engl J Med. 2012; 26: 1567-1576Crossref Scopus (1595) Google Scholar, 28Dixon J.B. O'Brien P.E. Playfair J. et al.Adjustable gastric banding and conventional therapy for type 2 diabetes: a randomized controlled trial.JAMA. 2008; 299: 316-323Crossref PubMed Scopus (1143) Google Scholar, 29Lee W.J. Chong K. Ser K.H. et al.Gastric bypass vs sleeve gastrectomy for type 2 diabetes mellitus: a randomized controlled trial.Arch Surg. 2011; 146: 143-148Crossref PubMed Scopus (347) Google Scholar] also include patients with BMI outside of this range (as low as 25 and as high as 43). Because the overlap in BMI is large, the level of evidence is high, and the importance of optimal treatment of diabetes is critical, the data from these studies have been included in this analysis. Additionally, there are 16 observational studies [31Cohen R. Pinheiro J.C. Schiavon C.A. Salles J.E. Wajchenberg B.L. Cummings D.E. Effects of gastric bypass surgery in patients with type 2 diabetes and only mild obesity.Diabetes Care. 2012; 35: 1420-1428Crossref PubMed Scopus (215) Google Scholar, 32Sultan S. Parikh M. Youn H. Kurian M. Fielding G. Ren C. Early U.S. outcomes after laparoscopic adjustable gastric banding in patients with a body mass index less than 35 kg/m2.Surg Endosc. 2009; 23: 1569-1573Crossref PubMed Scopus (45) Google Scholar, 33Angrisani L. Favretti F. Furbetta F. et al.Italian Group for Lap-Band System: results of multicenter study on patients with BMI≤35 kg/m2.Obes Surg. 2004; 14: 415-418Crossref PubMed Scopus (69) Google Scholar, 34Kakoulidis T.P. Karringer A. Gloaguen T. Arvidsson D. Initial results with sleeve gastrectomy for patients with class I obesity (BMI 30–35 kg/m2).Surg Obes Relat Dis. 2009; 5: 425-428Abstract Full Text Full Text PDF PubMed Scopus (28) Google Scholar, 35Choi J. Digiorgi M. Milone L. et al.Outcomes of laparoscopic adjustable gastric banding in patients with low body mass index.Surg Obes Relat Dis. 2010; 6: 367-371Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar, 36Abbatini F. Capoccia D. Casella G. Coccia F. Leonetti F. Basso N. Type 2 diabetes in obese patients with body mass index of 30–35 kg/m2: sleeve gastrectomy versus medical treatment.Surg Obes Relat Dis. 2012; 8: 20-24Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar, 37Gianos M. Abdemur A. Fendrich I. Gari V. Szomstein S. Rosenthal R.J. Outcomes of bariatric surgery in patients with body mass index<35 kg/m2.Surg Obes Relat Dis. 2012; 8: 25-30Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar, 38Huang C.K. Shabbir A. Lo C.H. Tai C.M. Chen Y.S. Houng J.Y. Laparoscopic Roux-en-Y gastric bypass for the treatment of type II diabetes mellitus in Chinese patients with body mass index of 25–35.Obes Surg. 2011; 21: 1344-1349Crossref PubMed Scopus (92) Google Scholar, 39Serrot F.J. Dorman R.B. Miller C.J. et al.Comparative effectiveness of bariatric surgery and nonsurgical therapy in adults with type 2 diabetes mellitus and body mass index<35 kg/m2.Surgery. 2011; 150: 684-691Abstract Full Text Full Text PDF PubMed Scopus (63) Google Scholar, 40Shah S.S. Todkar J.S. Shah P.S. Cummings D.E. Diabetes remission and reduced cardiovascular risk after gastric bypass in Asian Indians with body mass index<35 kg/m2.Surg Obes Relat Dis. 2010; 6: 332-338Abstract Full Text Full Text PDF PubMed Scopus (96) Google Scholar, 41Parikh M. Duncombe J. Fielding G.A. Laparoscopic adjustable gastric banding for patients with body mass index of≤35 kg/m2.Surg Obes Relat Dis. 2006; 2: 518-522Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar, 42Cohen R. Pinheiro J.S. Correa J.L. Schiavon C.A. Laparoscopic Roux-en-Y gastric bypass for BMI<35 kg/m2: a tailored approach.Surg Obes Relat Dis. 2006; 2: 401-404Abstract Full Text Full Text PDF PubMed Scopus (117) Google Scholar, 43Frenken M. Cho E.Y. Metabolic intestinal bypass surgery for type 2 diabetes in patients with a BMI<35 kg/m2: comparative analysis of 16 patients undergoing either BPD, BPD-DS, or RYGB.Obes Facts. 2011; 4: 13-17Crossref PubMed Scopus (7) Google Scholar, 44Scopinaro N. Adami G.F. Papadia F.S. et al.The effects of biliopancreatic diversion on type 2 diabetes mellitus in patients with mild obesity (BMI 30–35 kg/m2) and simple overweight (BMI 25–30 kg/m2): a prospective controlled study.Obes Surg. 2011; 21: 880-888Crossref PubMed Scopus (69) Google Scholar, 45Lee W.J. Ser K.H. Chong K. et al.Laparoscopic sleeve gastrectomy for diabetes treatment in nonmorbidly obese patients: efficacy and change of insulin secretion.Surgery. 2010; 147: 664-669Abstract Full Text Full Text PDF PubMed Scopus (139) Google Scholar, 46Demaria E.J. Winegar D.A. Pate V.W. Hutcher N.E. Ponce J. Pories W.J. Early postoperative outcomes of metabolic surgery to treat diabetes from sites participating in the ASMBS bariatric surgery center of excellence program as reported in the Bariatric Outcomes Longitudinal Database.Ann Surg. 2010; 252: 559-566PubMed Google Scholar] and 1 meta-analysis [[47]Li Q. Chen L. Yang Z. et al.Metabolic effects of bariatric surgery in type 2 diabetic patients with body mass index<35 kg/m2.Diabetes Obes Metab. 2012; 14: 262-270Crossref PubMed Scopus (71) Google Scholar] examining the effects of bariatric surgery on diabetes in patients with BMI<35 kg/m2. A summary of these studies is provided in Table 2, Table 3.Table 2Randomized trials and meta-analysis of bariatric surgery trials including patients with body mass index<35 kg/m2StudyTypeBMI rangeProcedureNDurationFollow-upWeight lossBMI changeHealth outcomesO’Brien 2006 [30]O'Brien P.E. Dixon J.B. Laurie C. et al.Treatment of mild to moderate obesity with laparoscopic adjustable gastric banding or an intensive medical program: a randomized trial.Ann Intern Med. 2006; 144: 625-633Crossref PubMed Scopus (412) Google ScholarRCT30–35LAGB versus medical therapy802 years97%87.2% EWL versus33.7 to 26.4 versusMetabolic syndrome 38% to 3% (P<.001) versus21.8% EWL (P<.001)33.5 to 31.5 (P<.001)38% to 24% (N.S.)Dixon 2008 [28]Dixon J.B. O'Brien P.E. Playfair J. et al.Adjustable gastric banding and conventional therapy for type 2 diabetes: a randomized controlled trial.JAMA. 2008; 299: 316-323Crossref PubMed Scopus (1143) Google ScholarRCT30–40LAGB versus medical therapy for T2DM602 years92%20.7% TWL36.9 to 29.5Remission of diabetes:versus 1.7% TWL(P<.001)versus 37.1 to 36.6(P<.001)22 of 30 (73%) versus 4 of 30 (13%)Lee 2011 [29]Lee W.J. Chong K. Ser K.H. et al.Gastric bypass vs sleeve gastrectomy for type 2 diabetes mellitus: a randomized controlled trial.Arch Surg. 2011; 146: 143-148Crossref PubMed Scopus (347) Google ScholarRCT25–35MGB versus LSG601 year100%MGB 94% EWLMGB 30 to 22.8HbA1cLSG 76% EWLLSG 30 to 24.4MGB 9.9% to 5.4%LSG 10.2% to 7.2%Higher rates of remission for MGB compared with LSGSchauer 2012 [5]Schauer P.R. Kashyap S.R. Wolski K. et al.Bariatric surgery versus intensive medical therapy in obese patients with diabetes.N Engl J Med. 2012; 26: 1567-1576Crossref Scopus (1595) Google ScholarRCT27–43 (34% of patients with BMI<35)LRYGB versus LSG versus IMT for T2DM1501 year93%LRYGB 88% EWLLRYGB –10.2% of patients withLSG 81% EWLLSG –8.9HbA1c<6.0:IMT 13% EWLIMT –1.9LRYGB 42%(P<.001 surgical groups compared with IMT)(P<.001 surgical groups compared with IMT)LSG 37%IMT 12% (P<.008 surgery versus IMT); significant reduction in cardiovascular medication in surgery groups versus IMTLi 2012 [47]Li Q. Chen L. Yang Z. et al.Metabolic effects of bariatric surgery in type 2 diabetic patients with body mass index<35 kg/m2.Diabetes Obes Metab. 2012; 14: 262-270Crossref PubMed Scopus (71) Google ScholarMeta-analysis<35 with T2DMRYGB (4 studies)DJB (3 studies)BPD (3 studies)MGB (2 studies)SG (1 study)357 (13 studies)6 months to 18 years (mean 27 months)NR–17 kg (P<.0001)–5.8 (P<.0001)FPG –4.4 mmol/LHbA1c –2.59%Triglycerides –56.7 mg/dLTotal Cholesterol –48.4 mg/dL(All changes P<.01)BMI = body mass index; RCT = randomized controlled trial; T2DM = type 2 diabetes mellitus; LAGB = laparoscopic adjustable gastric band; LSG = laparoscopic sleeve gastrectomy; IMT = intensive medical therapy; LRYGB = laparoscopic Roux-en-Y gastric bypass; RYGB = Roux-en-Y gastric bypass; DJB = duodenal-jejunal bypass; BPD = biliopancreatic diversion; N.S. = not significant; MGB = mini-gastric bypass; SG = sleeve gastrectomy; NR = not reported; EWL = excess weight loss; TWL = total weight loss; FPG = fasting plasma glucose; HbA1c = glycated hemoglobin. Open table in a new tab Table 3Observational studies including patients with body mass index<35 kg/m2StudyTypeBMI rangeProcedureNDurationFollow-upWeight lossBMI changeHealth outcomesAbbatini 2012 [36]Abbatini F. Capoccia D. Casella G. Coccia F. Leonetti F. Basso N. Type 2 diabetes in obese patients with body mass index of 30–35 kg/m2: sleeve gastrectomy versus medical treatment.Surg Obes Relat Dis. 2012; 8: 20-24Abstract Full Text Full Text PDF PubMed Scopus (36) Google ScholarProspective cohort matched for severity of T2DM30–35Sleeve gastrectomy (n = 9)181 year100%NRLSG 32.7 to 21.1DM Remission:versusMT 32.9 to 31.7LSG 8/9standard medical therapy for T2DM (n = 9)MT 0/9HbA1c: LSG 8.1% to 5.9% `MT 7.5% to 8.2%Gianos 2012 [37]Gianos M. Abdemur A. Fendrich I. Gari V. Szomstein S. Rosenthal R.J. Outcomes of bariatric surgery in patients with body mass index<35 kg/m2.Surg Obes Relat Dis. 2012; 8: 25-30Abstract Full Text Full Text PDF PubMed Scopus (18) Google ScholarRetrospective review30–35LSG (n = 24)4214 months95%Mean 41.4 lb weight loss33.9 to 26.525 patients with T2DM:LRYGB (n = 8) 20% remissionLAGB (n = 10) 48% improvement27 patients with HTN:33% remission52% improvement25 patients with Dyslipidemia: 20% remission 52% improvement 28% no changeCohen 2012 [31]Cohen R. Pinheiro J.C. Schiavon C.A. Salles J.E. Wajchenberg B.L. Cummings D.E. Effects of gastric bypass surgery in patients with type 2 diabetes and only mild obesity.Diabetes Care. 2012; 35: 1420-1428Crossref PubMed Scopus (215) Google ScholarProspective observational study30–35LRYGB66Median 5 year f/u (range 1–6)100%36% total weight lossNRDM remission 88%DM improvement 11%HbA1c 9.7% to 5.9%significant improvements in SBP, DBP, total cholesterol, LDL, HDL, triglycerides and predicted 10-year CV riskHuang 2011 [38]Huang C.K. Shabbir A. Lo C.H. Tai C.M. Chen Y.S. Houng J.Y. Laparoscopic Roux-en-Y gastric bypass for the treatment of type II diabetes mellitus in Chinese patients with body mass index of 25–35.Obes Surg. 2011; 21: 1344-1349Crossref PubMed Scopus (92) Google ScholarProspective observational study25–35LRYGB221 year100%NR30.8 to 23.7T2DM:HbA1c 9.2% to 5.9%FPG 204 to 103 mg/dLRemission 63.6%Improvement 36.4%Serrot 2011 [39]Serrot F.J. Dorman R.B. Miller C.J. et al.Comparative effectiveness of bariatric surgery and nonsurgical therapy in adults with type 2 diabetes mellitus and body mass index<35 kg/m2.Surgery. 2011; 150: 684-691Abstract Full Text Full Text PDF PubMed Scopus (63) Google ScholarRetrospective review30–35LRYGB (n = 17) versus MT (n = 17) for T2DM341 year100%LRYGB 70% EWLLRYGB –8.8HbA1c:(–57 lbs)MT no changeLRYGB 8.2% to 6.1% (P<.001)MT no changeCMT no changeFrenkenRetrospective review26–34.5BPD, DS, RYGB161 year94%NR32 to 25HbA1c:2011 [43]Frenken M. Cho E.Y. Metabolic intestinal bypass surgery for type 2 diabetes in patients with a BMI<35 kg/m2: comparative analysis of 16 patients undergoing either BPD, BPD-DS, or RYGB.Obes Facts. 2011; 4: 13-17Crossref PubMed Scopus (7) Google ScholarBPD, DS 8.8% to 5.2%RYGB 7.8% to 6.7%Scopinaro 2011 [44]Scopinaro N. Adami G.F. Papadia F.S. et al.The effects of biliopancreatic diversion on type 2 diabetes mellitus in patients with mild obesity (BMI 30–35 kg/m2) and simple overweight (BMI 25–30 kg/m2): a prospective controlled study.Obes Surg. 2011; 21: 880-888Crossref PubMed Scopus (69) Google ScholarProspective study25–30BPD152 years100%25–30: 80.4 to 70.9 kg25–30: 28.1 to 24.6HbA1c:30–351530–35: 89.2 to 73.7 kg30–35: 33.1 to 27.425–30: 9.1% to 6.9%30–35: 9.5% to 5.9%Higher remission rates of T2DM in obese versus overweight patientsLee 2010 [45]Lee W.J. Ser K.H. Chong K. et al.Laparoscopic sleeve gastrectomy for diabetes treatment in nonmorbidly obese patients: efficacy and change of insulin secretion.Surgery. 2010; 147: 664-669Abstract Full Text Full Text PDF PubMed Scopus (139) Google ScholarProspective study25–35LSG201 year100%69.10%31.0 to 24.6DM remission in 10/20 (50%) of patientsPreop C-peptide>3 predicted DM remissionDeMaria 2010 [46]Demaria E.J. Winegar D.A. Pate V.W. Hutcher N.E. Ponce J. Pories W.J. Early postoperative outcomes of metabolic surgery to treat diabetes from sites participating in the ASMBS bariatric surg