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

Obesity, hypertension, and chronic kidney disease

Obesity is a major risk factor for essential hypertension, diabetes, and other comorbid conditions that contribute to development of chronic kidney disease. Obesity raises blood pressure by increasing renal tubular sodium reabsorption, impairing pressure natriuresis, and causing volume expansion via activation of the sympathetic nervous system and renin–angiotensin–aldosterone system and by physical compression of the kidneys, especially when there is increased visceral adiposity. Other factors such as inflammation, oxidative stress, and lipotoxicity may also contribute to obesity-mediated hypertension and renal dysfunction. Initially, obesity causes renal vasodilation and glomerular hyperfiltration, which act as compensatory mechanisms to maintain sodium balance despite increased tubular reabsorption. However, these compensations, along with increased arterial pressure and metabolic abnormalities, may ultimately lead to glomerular injury and initiate a slowly developing vicious cycle that exacerbates hypertension and worsens renal injury. Body weight reduction, via caloric restriction and increased physical activity, is an important first step for management of obesity, hypertension, and chronic kidney disease. However, this strategy may not be effective in producing long-term weight loss or in preventing cardiorenal and metabolic consequences in many obese patients. The majority of obese patients require medical therapy for obesity-associated hypertension, metabolic disorders, and renal disease, and morbidly obese patients may require surgical interventions to produce sustained weight loss.

Mechanisms of changes in glucose metabolism and bodyweight after bariatric surgery

Bariatric surgery is the most effective treatment for obesity and also greatly improves glycaemic control, often within days after surgery, independently of weight loss. Laparoscopic adjustable gastric banding (LAGB) was designed as a purely restrictive procedure, whereas vertical sleeve gastrectomy (VSG) and Roux-en-Y gastric bypass (RYGB) induce changes in appetite through regulation of gut hormones, resulting in decreased hunger and increased satiation. Thus, VSG and RYBG more frequently result in remission of type 2 diabetes than does LAGB. With all three of these procedures, remission of diabetes is associated with early increases in insulin sensitivity in the liver and later in peripheral tissues; VSG and RYBG are also associated with improved insulin secretion and an exaggerated postprandial rise in glucagon-like peptide 1. The vagal pathway could have a role in the neurohumoral regulatory pathways that control appetite and glucose metabolism after bariatric surgery. Recent research suggests that changes in bile acid concentrations in the blood and altered intestinal microbiota might contribute to metabolic changes after surgery, but the mechanisms are unclear. In this Series paper, we explore the possible mechanisms underlying the effects on glucose metabolism and bodyweight of LAGB, VSG, and RYGB surgery. Elucidation of these mechanisms is providing knowledge about bodyweight regulation and the pathophysiology of type 2 diabetes, and could help to identify new drug targets and improved surgical techniques.

Beyond BMI: the need for new guidelines governing the use of bariatric and metabolic surgery

Bariatric surgery use is largely governed worldwide by a 1991 National Institutes of Health consensus statement that advocates BMI as the primary operative criterion and restricts surgery to severely obese patients. These guidelines have been enormously valuable in standardising practice, thereby facilitating accumulation of a copious database of information regarding long-term surgical benefits and risks, from vast clinical experience and research. However, the National Institutes of Health recommendations had important limitations from the outset and are now gravely outdated. They do not account for remarkable advances in minimally invasive surgical techniques or the development of entirely new procedures. In the two decades since they were crafted, we have gained far greater understanding of the dramatic, weight-independent benefits of some operations on metabolic diseases, especially type 2 diabetes, and of the inadequacy of BMI as a primary criterion for surgical selection. Furthermore, there is now a substantial and rapidly burgeoning body of level-1 evidence from randomised trials comparing surgical versus non-surgical approaches to obesity, type 2 diabetes, and other metabolic diseases, including among only mildly obese or merely overweight patients. Herein, we present arguments to impel the development of new guidelines for the use of bariatric and so-called metabolic surgery to inform clinical practice and insurance compensation.

Metabolic surgery: shifting the focus from glycaemia and weight to end-organ health

Bariatric surgery is the most effective treatment for weight loss and glycaemic control. The focus of clinical studies and clinical experience has predominantly been on the numerical reductions of bodyweight and glucose after surgery. In this Series paper, we examine evidence on the efficacy of bariatric surgery for pancreatic, renal, retinal, peripheral nervous, cardiovascular, hepatic, and reproductive end-organ damage or disease. The overall conclusions are that, in most cases, patients' end-organ damage is expected to either stabilise or improve postoperatively. However, some of these clinical outcomes have not been assessed with robust methods and, in many cases, do not have support from randomised controlled clinical trials comparing bariatric surgery with non-surgical interventions. Such trials are urgently needed to inform patients and clinicians on whether the risks of surgery outweigh the significant benefits for end-organ health.

Surgical management of obesity in patients with morbid obesity and nonalcoholic fatty liver disease

Most patients with severe complex obesity presenting for bariatric-metabolic surgery have nonalcoholic fatty liver disease (NAFLD). NAFLD is associated with central obesity, insulin resistance, type 2 diabetes, hypertension, and obesity-related dyslipidemia. Weight loss should be a primary therapy for NAFLD. However, evidence supporting intentional weight loss as a therapy for NAFLD is limited. Bariatric-metabolic surgery provides the most reliable method of achieving substantial sustained weight loss and the most commonly used procedures are associated with reduced steatosis and lobular inflammatory changes, but there are mixed reports regarding fibrosis. Surgery should complement treatment of obesity-related comorbidity, but not replace established therapy.

STAMPEDE: Bariatric surgery gains more evidence based support

Diabetes mellitus (DM) and obesity are associated with significant morbidity and mortality. Recent large-scale trials of intensive medical management for obesity and diabetes have been disappointing. Observational studies and small-scale trials of bariatric surgery on DM patients have shown promising results. The effects of sleeve gastrectomy and gastric bypass in a larger cohort of patients with DM and obesity was tested in the STAMPEDE trial over a 3-year follow-up.

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.

Systematic review with meta-analysis: non-alcoholic steatohepatitis - a case for personalised treatment based on pathogenic targets

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is an umbrella term, which encompasses simple steatosis and non-alcoholic steatohepatitis (NASH). The entire spectrum of NAFLD has been associated with metabolic syndrome. NASH is associated with increased mortality compared with that of the general population. Many therapeutic options for NASH have been studied. However, there is very little evidence supporting the efficacy of most regimens for the treatment of NASH.

AIM

To provide a review focusing on the current therapeutic options available for patients with NASH as well as to briefly introduce possible future interventions.

METHODS

A MEDLINE, Pubmed and Cochrane Review database search using a combination of keywords, which included non-alcoholic fatty liver disease, non-alcoholic hepatic steatosis, NAFLD, NASH, treatment, therapeutics, vitamin E, orlistat and bariatric surgery. An overall summary of the articles was developed for each section of discussion in this review.

RESULTS

NASH associated with metabolic syndrome can progress advanced fibrosis and cirrhosis. Weight loss and lifestyle modification have been shown to improve NASH. Other medications used for weight loss and metabolic syndrome have been evaluated, such as orlistat, metformin and thiazolidinediones. Alternative regimens using ursodeoxycholic acid, statins and probiotics as well as bariatric surgery have been evaluated, but have not been recommended as first-line treatment for NASH. Vitamin E for NASH patients without diabetes seems to be promising. The lack of effective treatment for NASH suggests the heterogeneity of patients presenting with the NASH phenotype. The best treatment strategy for these patients may be to identify their pathogenic target and develop personalised treatment protocols.

CONCLUSIONS

Currently, there are few options available for the management of NASH. Future targeted treatment strategies based on the pathogenic pathways may be needed to develop effective treatment for patients with NASH.

Importance of cardiovascular disease risk management in patients with type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is commonly accompanied by other cardiovascular disease (CVD) risk factors, such as hypertension, obesity, and dyslipidemia. Furthermore, CVD is the most common cause of death in people with T2DM. It is therefore of critical importance to minimize the risk of macrovascular complications by carefully managing modifiable CVD risk factors in patients with T2DM. Therapeutic strategies should include lifestyle and pharmacological interventions targeting hyperglycemia, hypertension, dyslipidemia, obesity, cigarette smoking, physical inactivity, and prothrombotic factors. This article discusses the impact of modifying these CVD risk factors in the context of T2DM; the clinical evidence is summarized, and current guidelines are also discussed. The cardiovascular benefits of smoking cessation, increasing physical activity, and reducing low-density lipoprotein cholesterol and blood pressure are well established. For aspirin therapy, any cardiovascular benefits must be balanced against the associated bleeding risk, with current evidence supporting this strategy only in certain patients who are at increased CVD risk. Although overweight, obesity, and hyperglycemia are clearly associated with increased cardiovascular risk, the effect of their modification on this risk is less well defined by available clinical trial evidence. However, for glucose-lowering drugs, further evidence is expected from several ongoing cardiovascular outcome trials. Taken together, the evidence highlights the value of early intervention and targeting multiple risk factors with both lifestyle and pharmacological strategies to give the best chance of reducing macrovascular complications in the long term.

The sum of many parts: potential mechanisms for improvement in glucose homeostasis after bariatric surgery

Bariatric surgery has emerged as the most durably effective treatment of type 2 diabetes (DM). However, the mechanisms governing improvement in glucose homeostasis have yet to be fully elucidated. In this review we discuss the various types of surgical interventions and the multitude of factors that potentially mediate the effects on glycemia, such as altered delivery of nutrients to the distal ileum, duodenal exclusion, gut hormone changes, bile acid reabsorption, and amino acid metabolism. Accumulating evidence that some of these changes seem to be independent of weight loss questions the rationale of using body mass index as the major indication for surgery in diabetic patients. Understanding the complex mechanisms and interactions underlying improved glycemic control could lead to novel therapeutic targets and would also allow for greater individualization of therapy and optimization of surgical outcomes.

Treatment of the obese patient in primary care: targeting and meeting goals and expectations

Obesity is a serious disease associated with increased patient risk of several comorbidities, including type 2 diabetes mellitus, cardiovascular disease, dyslipidemia, hypertension, some cancers, and greater mortality. Furthermore, obesity has a deleterious impact on quality of life and increases health care costs. Moderate weight loss of 5% to 10% has been shown to significantly improve several patient cardiometabolic risk factors and physical functioning, however, it is often difficult to begin the weight-loss conversation with patients. Primary care providers play a critical role in discussing the health effects of excess weight with patients, managing obesity-related comorbidities, and recommending appropriate weight-loss strategies. Open communication, realistic goal setting, and consistent monitoring are key factors in implementing an effective weight-loss program in the primary care setting. Although diet and lifestyle modifications are the first lines of approach and the foundation of any weight-loss strategy, in many cases, additional interventions may be necessary, including medical or surgical management. Herein, we discuss the approaches that primary care providers should consider when recommending appropriate weight-loss strategies for overweight/obese patients to achieve clinically meaningful weight loss, including pharmacotherapies approved for chronic management of patients with obesity, to be used as adjuncts to diet and lifestyle modifications, and surgical options.

Obesity consults--comprehensive obesity management in 2013: understanding the shifting paradigm

Although serious health concerns are associated with obesity, losing even 5% of body weight can produce clinically relevant effects. The initial goal of obesity management is usually a 5% to 10% weight reduction. Some people will sustain weight loss with changes in diet and exercise alone; however, these patients represent the minority, and a large percentage are unable to maintain weight loss over time. Patients and providers often wish to intensify obesity treatment, and therefore interest in new medications has been considerable. Until recently, only two antiobesity medications have received Food and Drug Administration approval for long-term use. In June and July of 2012, respectively, lorcaserin and combination phentermine/topiramate extended-release were approved for obesity therapy. The first section of this article reviews mechanisms, clinical trials, benefits and risks of available medications for treating obesity. Bariatric surgery is the next step for patients with a body mass index of ≥40 kg/m(2) or ≥35 kg/m(2) with comorbidities, based on National Institutes of Health Clinical Guidelines. These procedures and their risks and benefits are reviewed in the second section. The final section presents common clinical scenarios with guidance for choosing among evidence-based recommendations for developing optimal, individualized, long-term strategies for patients with obesity.

Moral challenges with surgical treatment of type 2 diabetes

AIM

To review the most important moral challenges following from the widespread use of bariatric surgery for type 2 diabetes for patients with BMI <35kg/m(2), although high quality evidence for its short and long term effectiveness and safety is limited.

METHODS

Extensive literature search to identify and analyze morally relevant issues. A question based method in ethics was applied to facilitate assessment and decision making.

RESULTS

Several important moral issues were identified: assessing and informing about safety, patient outcomes, and stakeholder interests; acquiring valid informed consent; defining and selecting outcome measures; stigmatization and discrimination of the patient group, as well as providing just distribution of health care. The main sources of these challenges are lack of high quality evidence, disagreement on clinical indications and endpoints, and the disciplining of human behavior by surgical interventions.

CONCLUSION

A lack of high quality evidence on the effect of bariatric surgery for the treatment of T2DM in patients with BMI<35/kg/m(2) poses a wide variety of moral challenges, which are important for decisions on the individual patient level, on the management level, and on the health policy making level. Strong preferences among surgeons and patients may hamper high quality research.

Bariatric surgery versus non-surgical treatment for obesity: a systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To quantify the overall effects of bariatric surgery compared with non-surgical treatment for obesity.

DESIGN

Systematic review and meta-analysis based on a random effects model.

DATA SOURCES

Searches of Medline, Embase, and the Cochrane Library from their inception to December 2012 regardless of language or publication status.

ELIGIBILITY CRITERIA

Eligible studies were randomised controlled trials with ≥ 6 months of follow-up that included individuals with a body mass index ≥ 30, compared current bariatric surgery techniques with non-surgical treatment, and reported on body weight, cardiovascular risk factors, quality of life, or adverse events.

RESULTS

The meta-analysis included 11 studies with 796 individuals (range of mean body mass index at baseline 30-52). Individuals allocated to bariatric surgery lost more body weight (mean difference -26 kg (95% confidence interval -31 to -21)) compared with non-surgical treatment, had a higher remission rate of type 2 diabetes (relative risk 22.1 (3.2 to 154.3) in a complete case analysis; 5.3 (1.8 to 15.8) in a conservative analysis assuming diabetes remission in all non-surgically treated individuals with missing data) and metabolic syndrome (relative risk 2.4 (1.6 to 3.6) in complete case analysis; 1.5 (0.9 to 2.3) in conservative analysis), greater improvements in quality of life and reductions in medicine use (no pooled data). Plasma triglyceride concentrations decreased more (mean difference -0.7 mmol/L (-1.0 to -0.4) and high density lipoprotein cholesterol concentrations increased more (mean difference 0.21 mmol/L (0.1 to 0.3)). Changes in blood pressure and total or low density lipoprotein cholesterol concentrations were not significantly different. There were no cardiovascular events or deaths reported after bariatric surgery. The most common adverse events after bariatric surgery were iron deficiency anaemia (15% of individuals undergoing malabsorptive bariatric surgery) and reoperations (8%).

CONCLUSIONS

Compared with non-surgical treatment of obesity, bariatric surgery leads to greater body weight loss and higher remission rates of type 2 diabetes and metabolic syndrome. However, results are limited to two years of follow-up and based on a small number of studies and individuals.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42012003317 (www.crd.york.ac.uk/PROSPERO).

Weight loss strategies for treatment of obesity

Obesity is one of the most serious and prevalent non-communicable diseases of the 21st century. It is also a patient-centered condition in which affected individuals seek treatment through a variety of commercial, medical and surgical approaches. Considering obesity as a chronic medical disease state helps to frame the concept of using a three-stepped intensification of care approach to weight management. As a foundation, all patients should be counseled on evidence-based lifestyle approaches that include diet, physical activity and behavior change therapies. At the second tier, two new pharmacological agents, phentermine-topiramate and lorcaserin, were approved in 2012 as adjuncts to lifestyle modification. The third step, bariatric surgery, has been demonstrated to be the most effective and long-term treatment for individuals with severe obesity or moderate obesity complicated by comorbid conditions that is not responsive to non-surgical approaches. By using a medical model, clinicians can provide more proactive and effective treatments in assisting their patients with weight loss.

Potential benefits of weight loss in coronary heart disease

The prevalence of overweight, obesity and insulin resistance in patients with coronary heart disease (CHD) exceeds that of the general population. Obesity is associated with a constellation of coronary risk factors that predispose to the development and progression of CHD. Intentional weight loss, accomplished through behavioral weight loss and exercise, improves insulin sensitivity and associated cardio-metabolic risk factors such as lipid measures, blood pressure, measures of inflammation and vascular function both in healthy individuals and patients with CHD. Additionally, physical fitness, physical function and quality of life all improve. There is evidence that intentional weight loss prevents the onset of CHD in high risk overweight individuals. While weight loss associated improvements in insulin resistance, fitness and related risk factors strongly supports favorable prognostic effects in individuals with established CHD, further study is needed to determine if long-term clinical outcomes are improved.

Interdisciplinary European Guidelines on metabolic and bariatric surgery

In 2012, an outstanding expert panel derived from IFSO-EC (International Federation for the Surgery of Obesity-European Chapter) and EASO (European Association for the Study of Obesity), composed by key representatives of both Societies including past and present presidents together with EASO's OMTF (Obesity Management Task Force) chair, agreed to devote the joint Medico-Surgical Workshop of both institutions to the topic of metabolic surgery as a pre-satellite of the 2013 European Congress on Obesity (ECO) to be held in Liverpool given the extraordinarily advancement made specifically in this field during the past years. It was further agreed to revise and update the 2008 Interdisciplinary European Guidelines on Surgery of Severe Obesity produced in cooperation of both Societies by focusing in particular on the evidence gathered in relation to the effects on diabetes during this lustrum and the subsequent changes that have taken place in patient eligibility criteria. The expert panel composition allowed the coverage of key disciplines in the comprehensive management of obesity and obesity-associated diseases, aimed specifically at updating the clinical guidelines to reflect current knowledge, expertise and evidence-based data on metabolic and bariatric surgery.