Impact of laparoscopic adjustable gastric banding on type 2 diabetes

Neuroendocrine mechanisms underlying bariatric surgery: Insights from human studies and animal models

Obesity has reached epidemic proportions and, to date, bariatric surgery remains the only effective treatment for morbid obesity in terms of its capacity to achieve durable weight loss. Bariatric surgery procedures, including Roux-en-Y gastric bypass (RYGB), adjustable gastric banding (AGB) and sleeve gastrectomy (SG), have been the primary procedures conducted over the past decade, with SG increasing in popularity over the past 5 years at the expense of both RYGB and AGB. Although these procedures were initially proposed to function via restrictive or malabsorptive mechanisms, it is now clear that profound physiological changes underlie the metabolic improvements in patients who undergo bariatric surgery. Data generated in human patients and animal models highlight the rapid and sustained changes in gut hormones that coincide with these procedures. Furthermore, recent studies highlight the involvement of the nervous system, specifically the vagus nerve, in mediating the reduction in appetite and food intake following bariatric surgery. What is unclear is where these pathways converge and interact within the gut-brain axis and whether vagally-mediated circuits are sufficient to drive the metabolic sequalae following bariatric surgery.

The use of adjustable gastric bands for management of severe and complex obesity

BACKGROUND

Obesity levels in the UK have reached a sustained high and ∼4% of the population would be candidates for bariatric surgery based upon current UK NICE guidelines, which has important implications for Clinical Commissioning Groups.

SOURCES OF DATA

Summary data from Cochrane systematic reviews, randomized controlled trials (RCTs) and cohort studies.

AREAS OF AGREEMENT

Currently, the only treatment that offers significant and durable weight loss for those with severe and complex obesity is surgery. Three operations account for 95% of all bariatric surgery in the UK, but the NHS offers surgery to only a small fraction of those who could benefit. Laparoscopic adjustable gastric banding (gastric banding) has potentially the lowest risk and up-front costs of the three procedures.

AREAS OF CONTROVERSY

Reliable Level 1 evidence of the relative effectiveness of the operations is lacking.

GROWING POINTS

As a point intervention, weight loss surgery together with the chronic disease management strategy for obesity can prevent significant future disease and mortality, and the NHS should embrace both.

AREAS TIMELY FOR DEVELOPING RESEARCH

Better RCT evidence is needed including clinical effectiveness and economic analysis to answer the important question 'which is the best of the three operations most frequently performed?' This review considers the current evidence for gastric banding for the treatment of severe and complex obesity.

Bile Acids, FXR, and Metabolic Effects of Bariatric Surgery

Overweight and obesity represent major risk factors for diabetes and related metabolic diseases. Obesity is associated with a chronic and progressive inflammatory response leading to the development of insulin resistance and type 2 diabetes (T2D) mellitus, although the precise mechanism mediating this inflammatory process remains poorly understood. The most effective intervention for the treatment of obesity, bariatric surgery, leads to glucose normalization and remission of T2D. Recent work in both clinical studies and animal models supports bile acids (BAs) as key mediators of these effects. BAs are involved in lipid and glucose homeostasis primarily via the farnesoid X receptor (FXR) transcription factor. BAs are also involved in regulating genes involved in inflammation, obesity, and lipid metabolism. Here, we review the novel role of BAs in bariatric surgery and the intersection between BAs and immune, obesity, weight loss, and lipid metabolism genes.

Laparoscopic gastric banding resolves the metabolic syndrome and improves lipid profile over five years in obese patients with body mass index 30-40 kg/m(2.)

BACKGROUND

Obesity, metabolic syndrome (MS) and dyslipidemia are independent risk factors for cardiovascular disease. Bariatric surgery is increasingly recognized as an effective intervention for improving each of these risk factors. There are sparse data on the long-term durability of metabolic changes associated with bariatric surgery, in particular with laparoscopic gastric banding (LGB). Our objective was to evaluate the durability of metabolic changes associated with LGB in nonmorbid obesity.

METHODS

Fifty obese patients (BMI 30-40) with ≥1 obesity-related comorbidity were prospectively followed for five years. At follow-up, subjects underwent fasting blood measures, including lipid NMR spectroscopy and standard lipid profile.

RESULTS

Forty-seven patients (45 female, mean age 43.8 years) completed four years follow-up (46 completed five years). Baseline BMI was 35.1 ± 2.6. Subjects exhibited mean weight loss of 22.3 ± 7.9 kg (22.9 ± 7.4%) at year one and maintained this (19.8 ± 10.2%) over five years. At baseline, 43% (20/47) of subjects met criteria for MS. This was reduced to 15% (7/47) at year one and remained reduced over five years (13%, 6/46) (p < 0.001). There were reductions in triglycerides (p < 0.001) and increases in HDL cholesterol (HDL-C, p < 0.001) and HDL particle concentration (p = 0.02), with a trend toward increased HDL particle size (p = 0.06) at year five. Changes in triglycerides and HDL-C were more prominent in patients with MS at baseline, but unassociated with weight loss or waist circumference. Changes in HDL particle size and concentration were not associated with MS status, weight loss, waist circumference, or statin use.

CONCLUSIONS

LGB produces significant weight loss, resolution of MS and changes in lipid profile suggestive of beneficial HDL remodeling. These changes persist five years following LGB.

Predictive factors of insulin resistance resolution with adjustable gastric band surgery

INTRODUCTION

The aim of the study was to evaluate preoperative factors associated with remission of diabetes and weight loss after laparoscopic gastric band surgery.

MATERIAL AND METHODS

A retrospective cohort of 95 patients who had an adjustable gastric band placed were included. A preliminary descriptive study of prognostic factors was performed using the logistic regression model with SPSS 17.0. The independent variables were age, sex, body mass index (BMI), diabetes status and degree of obesity; dependent variables were the proportion of weight loss, change in diabetes status score and percent changes in fasting sugar and glycosylated hemoglobin.

RESULTS

The variables that were significantly associated with the percentage of changes in fasting blood sugar and glycated hemoglobin were: the degree of obesity in the first year; preoperative and diabetes status respectively. The analysis of the need for antidiabetic treatment using the modified diabetes status score showed preoperative BMI, age and gender as significant predictors.

CONCLUSIONS

In patients undergoing gastric band surgery, weight loss is the fundamental mechanism by which insulin sensitivity increases. This improvement in glucose metabolism is influenced by factors such as sex, age, insulin treatment, duration of diabetes and degree of preoperative obesity.

Control of type 2 diabetes after 1 year of laparoscopic adjustable gastric banding in the helping evaluate reduction in obesity (HERO) study

AIMS

The 5-year, open-label, prospective, observational helping evaluate reduction in obesity (HERO) study (N = 1106) examines efficacy and safety of the LAP-BAND AP(®) laparoscopic adjustable gastric band (LAGB) in obese patients. This interim analysis assessed the control of type 2 diabetes (T2D), 1 year after the implantation of the LAGB.

METHODS

Baseline T2D was defined by chart review or use of antidiabetic medications or haemoglobin A1c (HbA1c) ≥ 7.0%. Control of T2D at 1 year was defined as A1c <7.0% (with or without antidiabetic medications).

RESULTS

After 1 year, 187 of 273 patients with T2D at baseline had adequate data available to assess T2D status, of which 135 patients (72.2%) achieved target control of T2D compared with 42.8% control rate at baseline. Independent predictors of achieving target control at 1 year included the following: (i) shorter diabetes duration odds ratio (OR) 0.914 [95% confidence interval (CI), 0.839, 0.995, p = 0.038], (ii) not using insulin therapy OR 0.16 (95% CI, 0.06, 0.47, p < 0.001) and (iii) greater mean % weight loss OR 1.176 (95% CI, 1.093, 1.266, p < 0.001). Patients using insulin at baseline were 84% less likely to achieve control of T2D after 1 year; each additional year of diabetes at baseline reduced the likelihood of good control by 9%; and each 1% of weight loss increases the likelihood of good control by 18%. Rates of device-related adverse events and reoperations were low and were not significantly different between patients with and without baseline T2D at 1 year.

CONCLUSIONS

Greater % weight loss, not using insulin therapy, and shorter disease duration predicted increased likelihood of target control of T2D, 1 year after implantation of the LAGB.

Five-year weight loss experience of outpatients receiving laparoscopic adjustable gastric band surgery

BACKGROUND

This study evaluated the efficacy and safety of laparoscopic adjustable gastric banding (LAGB) in a large cohort of morbidly obese patients followed for up to 5 years.

METHODS

Morbidly obese patients, ≥ 16 years of age, who underwent LAGB surgery at the Surgical Weight Loss Clinic in Ontario, Canada, between May 2005 and January 2011 were eligible for this retrospective chart review. Electronic files were searched to identify all patients who met the inclusion/exclusion criteria. Demographics, weights at baseline and follow-up visits (up to 60 months following surgery), and post-operative complications were documented. As follow-up visits occurred at unevenly spaced intervals within and across patients, modeling methods were used to more accurately assess mean % weight loss (WL) and % excess weight loss (EWL) over time.

RESULTS

This study included 2,815 patients (82 % female, mean age 43 years, mean baseline BMI 44.6 kg/m(2)) followed for a mean of 21.8 ± 15.4 months. Complications developed in 238 patients (8.5 %), the most frequent being prolapse/slippage (4.2 %), tubing/access port problems (1.2 %), and explantation (1.2 %). Mean %WL and %EWL progressed continuously over the first 2.5 years post-LAGB, plateauing at 20 and 49 %, respectively, for up to 5 years of follow up. Factors associated with increased weight loss were time since surgery, greater baseline weight (excess weight), older age at time of surgery, and male gender.

CONCLUSIONS

Weight loss was maintained for up to 5 years in our population of patients who underwent LAGB for the treatment of morbid obesity.

Long-term diabetic response to gastric bypass

BACKGROUND

As obesity and type II diabetes continue to rise, bariatric surgery offers a solution, but few long-term studies are available. The purpose of this study was to evaluate the long-term outcomes of diabetic patients after gastric bypass.

MATERIALS AND METHODS

This was a retrospective cohort study of all diabetic patients undergoing gastric bypass at our institution, from 1998 to 2012. Patients were compared by postoperative diabetic response to treatment (i.e., response = off oral medication/insulin versus refractory = on oral medication/insulin) and followed at 1-, 3-, 5-, and 10-y intervals. Continuous data were analyzed using Student t-test or Wilcoxon rank-sum test. Multivariable, Cox proportional hazard regression model was performed to compute diabetic cure ratios and 95% confidence intervals.

RESULTS

A total of 2454 bariatric surgeries were performed at our institution during the time period. A total of 707 diabetic patients were selected by Current Procedural Terminology codes for gastric bypass. Mean follow-up was 2.1 y. Incidence of diabetic response was 56% (1 y), 58% (3 y), 60% (5 y), and 44% (10 y). Postoperatively, responsive patients experienced greater percentage of total body weight loss (1 y [P < 0.0001], 3 y [P = 0.0087], and 5 y [P = 0.013]), and less hemoglobin A1c levels (1 y [P = 0.035] and 3 y [P = 0.040]) at follow-up than refractory patients. Multivariable analysis revealed a significant, independent inverse trend in incidence of diabetic cure as both age and body mass index decreased (Ptrend = 0.0019 and <0.0001, respectively). In addition, degenerative joint disease was independently associated with responsive diabetes (cure ratio = 1.6 [95% confidence interval = 1.1-2.2]).

CONCLUSIONS

At follow-up, both groups in our study experienced substantial weight loss; however, a greater loss was observed among the response group. Further research is needed to evaluate methods for optimizing patient care preoperatively and improving patient follow-up.

The business case for bariatric surgery revisited: a non-randomized case-control study

BACKGROUND AND AIM

Prior studies reporting that bariatric surgery (including laparoscopic adjustable gastric band (LAGB) and [laparoscopic Roux-en-Y] Gastric Bypass (LRYGB)) is cost-saving relied on a comparison sample of those with a morbid obesity (MO) diagnosis code, a high cost group who may not be reflective of those who opt for the procedures. We re-estimate net costs and time to breakeven using an alternative sample that does not rely on this code.

MATERIALS AND METHODS

Non-randomized case-control study using medical claims data from a commercial database in the USA. LAGB and LRYGB claimants were propensity score matched to two control samples: one restricted to those with a MO diagnosis code and one without this restriction.

RESULTS

When using the MO sample, costs for LAGB and LRYGB are recovered in 1.5 (Confidence Interval [CI]: 1.45 to 1.55) and 2.25 years (CI: 2.07 to 2.43), and 5 year savings are $78,980 (CI: 62,320 to 100,550) for LAGB and $61,420 (CI: 44,710 to 82,870) for LRYGB. Without the MO requirement, time to breakeven for LAGB increases to 5.25 (CI: 4.25 to 10+) years with a 5 year net cost of $690 (CI: 6,800 to 8.400). For LRYGB, time to breakeven exceeds 10 years and 5 year net costs are $18,940 (CI: 10,390 to 26,740).

CONCLUSIONS

The net costs and time to breakeven resulting from bariatric surgery are likely less favorable than has been reported in prior studies, and especially for LRYGB, with a time to breakeven of more than twice the 5.25 year estimate for LAGB.

Safety and effectiveness of LAP-BAND AP System: results of Helping Evaluate Reduction in Obesity (HERO) prospective registry study at 1 year

BACKGROUND

Laparoscopic adjustable gastric banding has several distinctive features, including band adjustability, easy reversibility, and lack of malabsorption, which contribute to its widespread use. The LAP-BAND AP System (LBAP; Allergan, Inc.), a redesigned and improved version of the original device, was approved by the US Food and Drug Administration in 2006. Because of limited information on LBAP, this study prospectively assesses the efficacy and safety of LBAP in real-world settings at clinical centers located in North America, Europe, and Australia.

STUDY DESIGN

This interim report of the ongoing 5-year prospective, observational, international, multicenter registry, Helping Evaluate Reduction in Obesity (HERO) Study (NCT00953173), describes clinical efficacy and safety of LBAP in real-world settings at 1 year.

RESULTS

One thousand one hundred and six patients were implanted with LBAP and 1-year data were available from 834 patients for efficacy analysis. At 1 year, the mean (SD) percentage of excess weight loss was 39.8% (22.3%), of weight loss was 16.9% (9.0%), and the mean (SD) body mass index decreased to 37.7 (7.0) kg/m(2) from 45.1 (6.9) kg/m(2) at baseline. Patients with type 2 diabetes mellitus or hypertension showed significant improvements at 1 year post LBAP (both p < 0.005). The most common device-related complications were port displacement (n = 20 [1.8%]), pouch dilation (n = 12 [1.1%]), band slippage (n = 7 [0.6%]), and band erosion (n = 5 [0.5%]). Eighteen (1.6%) patients had the device explanted.

CONCLUSIONS

At 1 year post LBAP, progressive weight loss was associated with improvement and/or resolution of comorbid conditions and was safe and well tolerated. Patient follow-up continues.

GLP-1R agonism enhances adjustable gastric banding in diet-induced obese rats

Bariatric procedures vary in efficacy, but overall are more effective than behavioral and pharmaceutical treatment. Roux-en-Y gastric bypass causes increased secretion of glucagon-like peptide 1 (GLP-1) and reduces body weight (BW) more than adjustable gastric banding (AGB), which does not trigger increased GLP-1 secretion. Since GLP-1-based drugs consistently reduce BW, we hypothesized that GLP-1 receptor (GLP-1R) agonists would augment the effects of AGB. Male Long-Evans rats with diet-induced obesity received AGB implantation or sham surgery. GLP-1R agonism, cannabinoid receptor-1 (CB1-R) antagonism, or vehicle was combined with inflation to evaluate interaction between AGB and pharmacological treatments. GLP1-R agonism reduced BW in both sham and AGB rats (left uninflated) compared with vehicle-treated animals. Subsequent band inflation was ineffective in vehicle-treated rats but enhanced weight loss stimulated by GLP1-R agonism. In contrast, there was no additional BW loss when CB1-R antagonism was given with AGB. We found band inflation to trigger neural activation in areas of the nucleus of the solitary tract known to be targeted by GLP-1R agonism, offering a potential mechanism for the interaction. These data show that GLP-1R agonism, but not CB1-R antagonism, improves weight loss achieved by AGB and suggest an opportunity to optimize bariatric surgery with adjunctive pharmacotherapy.

LAP-BAND for lower BMI: 2-year results from the multicenter pivotal study

OBJECTIVE

The goal of this study was to examine the safety and effectiveness of the LAP-BAND System for patients with 30-39.9 BMI and associated comorbidities.

DESIGN AND METHODS

In this prospective, multicenter, interventional cohort study, subjects with a BMI between 30 and 39.9 who had failed prior weight loss attempts were recruited from 7 surgical centers. The primary effectiveness endpoint required that >40% of subjects achieve ≥30% excess weight loss (EWL) at 1 year. Secondary endpoints included assessment of comorbidities and quality-of-life.

RESULTS

Of 149 subjects, 90.6% were female, with mean BMI of 35.3 kg/m2 . At 1 year, 84.6% of subjects achieved ≥30% EWL (P < 0.0001), with 65.0% mean EWL; 66.4% of subjects were no longer obese (BMI < 30). Baseline comorbidities improved at 1 year for 64.4% with dyslipidemia, 59.6% with hypertension, and 85.7% with diabetes. Quality-of-life (IWQOL-Lite) also improved (P < 0.0001). The Year 1 results were maintained or improved at 2 years. Regression analysis indicates that each additional 10% weight loss at Year 2 was associated with an increase in IWQOL-Lite by 7.1 points and a decrease in triglycerides by 13.7 mg/dL, fasting glucose by 3.5 mg/dL, and systolic blood pressure by 3.3 mmHg. Most adverse events were mild to moderate and resolved without sequelae within 1 month. Five subjects (3.4%) had explantations.

CONCLUSION

LAGB is safe and effective for people with 30-39.9 BMI, with weight loss and comorbidity improvement through at least 2 years.

Long-term dietary intake and nutritional deficiencies following sleeve gastrectomy or Roux-En-Y gastric bypass in a mediterranean population

BACKGROUND

Data on long-term dietary changes and nutritional deficiencies after sleeve gastrectomy (SG) in grade 3 obese patients are scarce.

OBJECTIVE

To prospectively compare dietary changes and nutritional deficiencies in grade 3 obese patients 5 years after SG and Roux-en-y gastric bypass (GBP).

PARTICIPANTS/SETTING

Three hundred and fifty-five patients who had SG (n=61) or GBP (n=294) (May 2001-December 2006) at a Spanish university hospital.

DESIGN

Longitudinal, prospective, observational study. PRIMARY OUTCOMES/STATISTICAL ANALYSES: Changes in energy, macronutrient, and micronutrient intake, and weight loss were analyzed using mixed models for repeated measurements.

RESULTS

At the 5-year follow-up visit, the percentage of excess weight loss (P=0.420) and daily energy intake (P=0.826), as well as the proportion of energy from carbohydrates (P=0.303), protein (P=0.600), and fat (P=0.541) did not differ between surgical groups. Energy intake (P=0.004), baseline weight (P<0.001), and time period (P<0.001), but not the proportion of different macronutrients or the type of surgery, independently predicted the percentage excess weight loss over time. After SG or GBP, the mean daily dietary intake of calcium, magnesium, phosphorus, and iron was less than the current recommendations. Despite universal supplementation, the prevalence of nutritional deficiencies was comparable after SG or GBP, with 25-hydroxyvitamin D being the most commonly observed deficiency (SG, 93.3% to 100%; GBP, 90.9% to 85.7%, P=not significant). In an adjusted multivariate regression model, energy intake and lipid intake independently predicted plasma 25(OH)-vitamin D levels.

CONCLUSIONS

Data show that SG and GBP are associated with similar long-term weight loss with no differences in terms of dietary intake. Furthermore, data demonstrate that both types of surgeries carry comparable nutritional consequences.

Use of genomic panels to determine risk of developing type 2 diabetes in the general population: a targeted evidence-based review

This evidence review addresses whether type 2 diabetes genomic risk panels improve health outcomes (e.g., reduce rates of developing type 2 diabetes) in low- or high-risk adults; two clinical scenarios promulgated by commercial companies offering such testing. Evidence for the analytic validity of available genomic profiles was inadequate. Clinical validity ranged from inadequate to convincing for 30 variants identified on five type 2 diabetes genomic panels and by genome-wide association studies. Eight common variants were identified for general population use; evidence credibility based on published criteria was strong for two variants, moderate for two variants, and weak for four variants. TCF7L2 had the largest per-allele odds ratio of 1.39 (95% confidence interval 1.33-1.46). Models combining the best four, best eight, and all 30 variants used summary effect sizes, reported genotype frequencies, and assumed independent effects. Areas under the curve were 0.547, 0.551, and 0.570, respectively. In high-risk populations, per-allele odds ratios for TCF7L2 alone were similar to those of the general population. TCF7L2, in combination with other variants, yielded minimal improvement in risk reclassification. Evidence on TCF7L2 clinical validity was adequate. Three studies addressed the clinical utility of intervention effectiveness, stratified by TCF7L2 genotype; none found significant interactions. Clinical utility evidence was inadequate. In addition to analytic validity and clinical utility knowledge gaps, additional gaps were identified regarding how to inform, produce, and evaluate models combining multiple variants.

Five-year changes in psychiatric treatment status and weight-related comorbidities following bariatric surgery in a veteran population

BACKGROUND

Although bariatric surgery is an established treatment for obesity, less is known regarding the long-term effects of surgery on psychiatric function. This paper reports changes in psychiatric treatment status, weight, and weight-related comorbidities over 5 years of follow-up among a population of veterans completing bariatric surgery.

METHODS

We assessed 55 veterans undergoing bariatric surgery at a single Veteran Affairs medical center for 5 years post-surgery. Patients completed a pre-surgery clinical interview with a licensed psychologist. Using computerized medical records, we tracked pre- to post-surgery involvement with antidepressants, anxiolytics, psychotherapies, and overall psychiatric treatment visits along with changes in weight and metabolic function.

RESULTS

Rates of antidepressant use and/or involvement with psychotherapy for depression declined from 56.4 % at pre-surgery to 34.6 % at 5 years post-surgery, p = 0.01. Anxiolytic use and/or involvement with psychotherapy for anxiety, however, increased from 23.6 to 32.7 % pre- to 5 years post-surgery. Average psychiatric treatment volume remained similar to pre-surgery status across follow-up. These mixed indicators of psychiatric improvement occurred despite marked metabolic improvements from surgery. Mean percent excess weight loss = 51.7 and 41.3 (1 and 5 years post-surgery, respectively), systolic blood pressure (-6.8 mmHg (14.3)/-6.1 mmHg (12.8), respectively), glucose levels (-18.6 mg/dL (30.2)/-10.0 mg/dL (25.9), respectively), triglycerides (-78.2 mg/dL (96.7)/-69.1 mg/dL (102.2), respectively) and high-density lipoproteins (+7.1 (9.9)/+11.3 (11.3), respectively) levels each improved.

CONCLUSIONS

We report evidence of decreased antidepressant use and depression therapies following bariatric surgery, but no improvements on rates of anxiolytic use and anxiety therapies or on overall psychiatric treatment involvement. Despite metabolic improvements, bariatric patients with psychiatric histories may warrant ongoing attention to mental health.

Metabolic changes one year after laparoscopic adjustable gastric banding operation in morbidly obese subjects

Introduction

Laparoscopic adjustable gastric banding (LAGB) is effective for weight reduction in severely obese patients. However, the data about its effect on metabolic syndrome (MS) are limited.

Aim

To assess weight loss and changes of metabolic parameters 1 year after LAGB in a prospective, nonrandomized single center cohort study in morbidly obese subjects.

Material and methods

Physical examination, body weight (BW) parameters and metabolic profile were assessed at baseline and 1 year after LAGB in morbidly obese subjects. The incidence of MS was evaluated according to National Cholesterol Education Program Adult Treatment Panel III criteria.

Results

One year after the operation data from 90 patients out of 103 were available. Mean excess weight (EW) loss of 33.1% was associated with a significant improvement in all metabolic parameters: decrease of hypertension by 15.8%, hypertriglyceridemia by 42.6%, and hyperglycemia by 46.3%; and increase in high density lipoprotein cholesterol by 48.3%. This resulted in the resolution of MS in 44.2% of subjects. The significant change in the distribution of MS components was observed with the highest frequency of 4 components before and 2 components after surgery. Patients with MS at baseline lost 29.9% of EW compared to 44.3% in those without MS (p = 0.009).

Conclusions

The LAGB resulted in effective reduction of BW parameters in morbidly obese subjects 1 year after the operation. Along with the weight loss, resolution of MS and a significant shift towards decrease in the number of MS components was observed. Patients with MS were more resistant to the weight loss.

Health benefits of gastric bypass surgery after 6 years

CONTEXT

Extreme obesity is associated with health and cardiovascular disease risks. Although gastric bypass surgery induces rapid weight loss and ameliorates many of these risks in the short term, long-term outcomes are uncertain.

OBJECTIVE

To examine the association of Roux-en-Y gastric bypass (RYGB) surgery with weight loss, diabetes mellitus, and other health risks 6 years after surgery.

DESIGN, SETTING, AND PARTICIPANTS

A prospective Utah-based study conducted between July 2000 and June 2011 of 1156 severely obese (body mass index [BMI] ≥ 35) participants aged 18 to 72 years (82% women; mean BMI, 45.9; 95% CI, 31.2-60.6) who sought and received RYGB surgery (n = 418), sought but did not have surgery (n = 417; control group 1), or who were randomly selected from a population-based sample not seeking weight loss surgery (n = 321; control group 2).

MAIN OUTCOME MEASURES

Weight loss, diabetes, hypertension, dyslipidemia, and health-related quality of life were compared between participants having RYGB surgery and control participants using propensity score adjustment.

RESULTS

Six years after surgery, patients who received RYGB surgery (with 92.6% follow-up) lost 27.7% (95% CI, 26.6%-28.9%) of their initial body weight compared with 0.2% (95% CI, -1.1% to 1.4%) gain in control group 1 and 0% (95% CI, -1.2% to 1.2%) in control group 2. Weight loss maintenance was superior in patients who received RYGB surgery, with 94% (95% CI, 92%-96%) and 76% (95% CI, 72%-81%) of patients receiving RYGB surgery maintaining at least 20% weight loss 2 and 6 years after surgery, respectively. Diabetes remission rates 6 years after surgery were 62% (95% CI, 49%-75%) in the RYGB surgery group, 8% (95% CI, 0%-16%) in control group 1, and 6% (95% CI, 0%-13%) in control group 2, with remission odds ratios (ORs) of 16.5 (95% CI, 4.7-57.6; P < .001) vs control group 1 and 21.5 (95% CI, 5.4-85.6; P < .001) vs control group 2. The incidence of diabetes throughout the course of the study was reduced after RYGB surgery (2%; 95% CI, 0%-4%; vs 17%; 95% CI, 10%-24%; OR, 0.11; 95% CI, 0.04-0.34 compared with control group 1 and 15%; 95% CI, 9%-21%; OR, 0.21; 95% CI, 0.06-0.67 compared with control group 2; both P < .001). The numbers of participants with bariatric surgery-related hospitalizations were 33 (7.9%), 13 (3.9%), and 6 (2.0%) for the RYGB surgery group and 2 control groups, respectively.

CONCLUSION

Among severely obese patients, compared with nonsurgical control patients, the use of RYGB surgery was associated with higher rates of diabetes remission and lower risk of cardiovascular and other health outcomes over 6 years.

Bariatric surgery for type 2 diabetes

Bariatric surgery provides substantial, sustained weight loss and major improvements in glycaemic control in severely obese individuals with type 2 diabetes. However, uptake of surgery in eligible patients is poor, and the barriers are difficult to surmount. We examine the indications for and efficacy and safety of conventional bariatric surgical procedures and their effect on glycaemic control in type 2 diabetes. How surgical gastrointestinal interventions achieve these changes is of great research interest, and is evolving rapidly. Old classifications about restriction and malabsorption are inadequate, and we explore understanding of putative mechanisms. Some bariatric procedures improve glycaemic control in people with diabetes beyond that expected for weight loss, and understanding this additional effect could provide insights into the pathogenesis of type 2 diabetes and assist in the development of new procedures, devices, and drugs both for obese and non-obese patients.