Roux en Y gastric bypass hypoglycemia resolves with gastric feeding or reversal: Confirming a non-pancreatic etiology

Changes in Symptoms and General Well-being After Reversal of Roux-en-Y Gastric Bypass: A Questionnaire Survey

PURPOSE

After Roux-en-Y gastric bypass (RYGB), few patients develop severe complications, which ultimately may require reversal of RYGB. We aimed to examine the effect of reversal of RYGB on symptoms and well-being.

MATERIALS AND METHODS

Via contact to medical and surgical departments treating patients with RYGB, we identified 18 patients, who had undergone reversal, 2009-2019. We conducted a Danish, nationwide questionnaire survey concerning symptoms before and after reversal of the RYGB including the patients' own perceptions of their well-being.

RESULTS

Fourteen patients responded to the questionnaire (86% female; median age at RYGB, 36.2 years [IQR, 30.9-38.6 years]). The median time from RYGB to reversal was 5.8 years (IQR, 5.1-7.5 years). After RYGB, 13 patients (93%) reported abdominal pain, while 12 patients still had abdominal pain after reversal. Six out of 11 patients (45%) reported complete remission of dumping/post-bariatric hypoglycemia (PBH) after reversal. Malabsorption disappeared in 10 out of 11 patients (90%). Reversal had minor effect on neuropathy. The median weight loss from RYGB was 61 kg (IQR, 56-75 kg), while the median weight regain after reversal was 30 kg (IQR, 13-46 kg). Regarding the well-being, 72 of the patients felt better or much better after reversal.

CONCLUSION

In total, 72% of the patients felt better or much better after reversal of RYGB, though some still had RYGB-related symptoms. The reversal relieved dumping/PBH and malabsorption, but not abdominal pain and neuropathy. Finally, half of the weight loss was regained after reversal. Reversal of RYGB may be an option in highly selected cases.

Postprandial hypoglycemia as a complication of bariatric and metabolic surgery: a comprehensive review of literature

Postprandial hypoglycemia (PPH) is a challenging and significant complication that can occur following bariatric and metabolic surgery. Symptoms of PPH are typical of hypoglycemia, such as sweating, weakness, disorientation, palpitation, etc. The complex nature of PPH is essential to achieve accurate diagnosis and effective management. This review aims to give extensive coverage of the intricate nature of PPH common with bariatric and metabolic surgery, outlining its pathogenesis, risk factors, clinical presentation, diagnostic strategies, and treatment options. The study explores various clinical forms and pathogenic mechanisms behind PPH while discussing diagnostic tools like continuous glucose monitoring or mixed meal tolerance tests. Furthermore, it considers possible interventions, including dietary changes, pharmaceutical therapies, and surgeries, to relieve symptoms and improve patient's quality of life. It aims to comprehensively understand how healthcare professionals can effectively manage this disorder for patients undergoing bariatric and metabolic surgery.

Bariatric surgery and diabetes: Current challenges and perspectives

Diabetes mellitus (DM) and obesity have become public issues of global concern. Bariatric surgery for the treatment of obesity combined with type 2 DM has been shown to be a safe and effective approach; however, there are limited studies that have systematically addressed the challenges of surgical treatment of obesity combined with DM. In this review, we summarize and answer the most pressing questions in the field of surgical treatment of obesity-associated DM. I believe that our insights will be of great help to clinicians in their daily practice.

Society for Endocrinology guidelines for the diagnosis and management of post-bariatric hypoglycaemia

Post bariatric hypoglycaemia (PBH) is typically a post-prandial hypoglycaemia occurring about 2-4 hours after eating in people who have undergone bariatric surgery. PBH develops relatively late after surgery and often after discharge from post-surgical follow-up by bariatric teams, leading to variability in diagnosis and management in non-specialist centres.

AIM

to improve and standardise clinical practice in the diagnosis and management of PBH.

OBJECTIVES

(1) to undertake an up-to-date review of the current literature; (2) to formulate practical and evidence-based guidance with regards on the diagnosis and treatment of PBH; (3) to recommend future avenues for research in this condition.

METHOD

A scoping review was undertaken after an extensive literature search. A consensus on the guidance and confidence in the recommendations was reached by the steering group authors prior to review by key stakeholders.

OUTCOME

We make pragmatic recommendations for the practical diagnosis and management of PBH including criteria for diagnosis and recognition, as well as recommendations for research areas that should be explored.

A Matched Comparative Analysis of Type-2 Diabetes Mellitus Remission Between Roux-en-Y Gastric Bypass and Sleeve Gastrectomy

OBJECTIVE

Multiple scores validate long-term type-2 diabetes mellitus (T2DM) remission after metabolic and bariatric surgery (MBS). However, studies comparing Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) have not adequately controlled for certain parameters, which may influence procedure selection.

METHODS

We conducted a multicenter retrospective review of patients with T2DM who underwent RYGB or SG between 2008 and 2017. Data on demographics, clinical, laboratory, and metabolic values were collected annually for up to 14 years. Each eligible RYGB patient was individually matched to an eligible SG patient based on diabetes severity, weight loss, and follow-up duration.

RESULTS

Among 1149 T2DM patients, 467 were eligible for matching. We found 97 matched pairs who underwent RYGB or SG. RYGB showed significantly higher T2DM remission rates (46.4%) compared to SG (33.0%) after matching. SG patients had higher insulin usage (35.1%) than RYGB patients (20.6%). RYGB patients also experienced greater decreases in HbA1c levels and diabetes medication usage than SG patients.

CONCLUSIONS

RYGB demonstrates higher efficacy for T2DM remission compared to SG, regardless of baseline characteristics, T2DM severity, weight loss, and follow-up duration. Further studies are needed to understand the long-term metabolic effects of MBS and the underlying pathophysiology of T2DM remission after MBS.

Duodenal enteroendocrine cells and GIP as treatment targets for obesity and type 2 diabetes

The duodenum is an important source of endocrine and paracrine signals controlling digestion and nutrient disposition, notably including the main incretin hormone glucose-dependent insulinotropic polypeptide (GIP). Bariatric procedures that prevent nutrients from contact with the duodenal mucosa are particularly effective interventions to reduce body weight and improve glycaemic control in obesity and type 2 diabetes. These procedures take advantage of increased nutrient delivery to more distal regions of the intestine which enhances secretion of the other incretin hormone glucagon-like peptide-1 (GLP-1). Preclinical experiments have shown that either an increase or a decrease in the secretion or action of GIP can decrease body weight and blood glucose in obesity and non-insulin dependent hyperglycaemia, but clinical studies involving administration of GIP have been inconclusive. However, a synthetic dual agonist peptide (tirzepatide) that exerts agonism at receptors for GIP and GLP-1 has produced marked weight-lowering and glucose-lowering effects in people with obesity and type 2 diabetes. This appears to result from chronic biased agonism in which the novel conformation of the peptide triggers enhanced signalling by the GLP-1 receptor through reduced internalisation while reducing signalling by the GIP receptor directly or via functional antagonism through increased internalisation and degradation.

Postbariatric surgery hypoglycemia: Nutritional, pharmacological and surgical perspectives

Post-bariatric hypoglycaemia (PBH) is a metabolic complication of bariatric surgery (BS), consisting of low post-prandial glucose levels in patients having undergone bariatric procedures. While BS is currently the most effective and relatively safe treatment for obesity and its complications, the development of PBH can significantly impact patients' quality of life and mental health. The diagnosis of PBH is still challenging, considering the lack of definitive and reliable diagnostic tools, and the fact that this condition is frequently asymptomatic. However, PBH's prevalence is alarming, involving up to 88% of the post-bariatric population, depending on the diagnostic tool, and this may be underestimated. Given the prevalence of obesity soaring, and an increasing number of bariatric procedures being performed, it is crucial that physicians are skilled to diagnose PBH and promptly treat patients suffering from it. While the milestone of managing this condition is nutritional therapy, growing evidence suggests that old and new pharmacological approaches may be adopted as adjunct therapies for managing this complex condition.

Transoral gastric outlet reduction for post-prandial hypoglycemia after Roux-en-Y gastric bypass

BACKGROUND

Post-prandial hypoglycemia is an uncommon but disabling late complication of Roux-en-Y gastric bypass (RYGB). Most patients can be treated with dietary interventions and medications; however, some patients develop refractory hypoglycemia that may lead to multiple daily episodes and seizures. While RYGB reversal surgery is an effective treatment, complication rates are high, and patients inevitably experience weight regain. Transoral gastric outlet reduction (TORe) is a minimally invasive treatment that is effective for early and late dumping syndrome. However, prior studies have not distinguished the effectiveness of TORe specifically for patients with post-prandial hypoglycemia. This study aims to describe a single institution's experience of TORe for treating post-prandial hypoglycemia.

METHODS

This is a case series of patients with prior RYGB complicated by post-prandial hypoglycemia who underwent TORe from February 2020 to September 2021. Pre-procedural characteristics and post-procedural outcomes were obtained. Outcomes assessed included post-prandial hypoglycemia episodes, dumping syndrome symptoms, and weight change.

RESULTS

A total of 11 patients underwent TORe from 2020 to 2021 for post-prandial hypoglycemia. Three (27%) patients had a history of seizures due to hypoglycemia. All had been advised on dietary changes, and ten patients (91%) were on medications for dumping. All patients reported a reduction in post-prandial hypoglycemic events as well as the majority of dumping syndrome symptoms during an average follow-up time of 409 ± 125 days. Ten patients (91%) had experienced weight regain from their post-RYGB nadir weight. For these patients, the average total body weight loss 12 months post-TORe was 12.4 ± 12%. There were no complications requiring hospitalization. One patient experienced post-TORe nausea and vomiting requiring dilation of the gastrojejunal anastomosis with resolution in symptoms.

CONCLUSION

TORe is a safe and effective treatment for post-prandial hypoglycemia and weight regain after RYGB in patients with symptoms refractory to medications and dietary changes.

An Imbalance of Pathophysiologic Factors in Late Postprandial Hypoglycemia Post Bariatric Surgery: A Narrative Review

With a rise in obesity and more patients opting for bariatric surgery, it becomes crucial to understand associated complications like postprandial hypoglycemia (PPH). After bariatric surgery, significant changes are seen in insulin sensitivity, beta cell function, glucagon-like peptide 1 (GLP-1) levels, the gut microbiome, and bile acid metabolism. And in a small subset of patients, exaggerated imbalances in these functional and metabolic processes lead to insulin-glucose mismatch and hypoglycemia. The main treatment for PPH involves dietary modifications. For those that do not respond, medications or surgical interventions are considered to reverse some of the imbalances. We present a few case reports of patients that safely tolerated GLP-1 agonists. However, larger randomized control trials are needed to further characterize PPH and understand its treatment.

Diagnosis and management of post-bariatric surgery hypoglycemia

INTRODUCTION

While bariatric surgery remains the most effective treatment for obesity that allows substantial weight loss with improvement and possibly remission of obesity-associated comorbidities, some postoperative complications may occur. Managing physicians need to be familiar with the common problems to ensure timely and effective management. Of these complications, postoperative hypoglycemia is an increasingly recognized complication of bariatric surgery that remains underreported and underdiagnosed.

AREA COVERED

This article highlights the importance of identifying hypoglycemia in patients with a history of bariatric surgery, reviews pathophysiology and addresses available nutritional, pharmacological and surgical management options. Systemic evaluation including careful history taking, confirmation of hypoglycemia and biochemical assessment is essential to establish accurate diagnosis. Understanding the weight-dependent and weight-independent mechanisms of improved postoperative glycemic control can provide better insight into the causes of the exaggerated responses that lead to postoperative hypoglycemia.

EXPERT OPINION

Management of post-operative hypoglycemia can be challenging and requires a multidisciplinary approach. While dietary modification is the mainstay of treatment for most patients, some patients may benefit from pharmacotherapy (e.g. GLP-1 receptor antagonist); Surgery (e.g. reversal of gastric bypass) is reserved for unresponsive severe cases. Additional research is needed to understand the underlying pathophysiology with a primary aim in optimizing diagnostics and treatment options.

The Importance of Endogenously Secreted GLP-1 and GIP for Postprandial Glucose Tolerance and β-Cell Function After Roux-en-Y Gastric Bypass and Sleeve Gastrectomy Surgery

Enhanced secretion of glucagon-like peptide 1 (GLP-1) seems to be essential for improved postprandial β-cell function after Roux-en-Y gastric bypass (RYGB) but is less studied after sleeve gastrectomy (SG). Moreover, the role of the other major incretin hormone, glucose-dependent insulinotropic polypeptide (GIP), is relatively unexplored after bariatric surgery. We studied the effects of separate and combined GLP-1 receptor (GLP-1R) and GIP receptor (GIPR) blockade during mixed-meal tests in unoperated (CON), SG-operated, and RYGB-operated people with no history of diabetes. Postprandial GLP-1 concentrations were highest after RYGB but also higher after SG compared with CON. In contrast, postprandial GIP concentrations were lowest after RYGB. The effect of GLP-1R versus GIPR blockade differed between groups. GLP-1R blockade reduced β-cell glucose sensitivity and increased or tended to increase postprandial glucose responses in the surgical groups but had no effect in CON. GIPR blockade reduced β-cell glucose sensitivity and increased or tended to increase postprandial glucose responses in the CON and SG groups but had no effect in the RYGB group. Our results support that GIP is the most important incretin hormone in unoperated people, whereas GLP-1 and GIP are equally important after SG, and GLP-1 is the most important incretin hormone after RYGB.

Glucose metabolism after bariatric surgery: implications for T2DM remission and hypoglycaemia

Although promising therapeutics are in the pipeline, bariatric surgery (also known as metabolic surgery) remains our most effective strategy for the treatment of obesity and type 2 diabetes mellitus (T2DM). Of the many available options, Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) are currently the most widely used procedures. RYGB and VSG have very different anatomical restructuring but both surgeries are effective, to varying degrees, at inducing weight loss and T2DM remission. Both weight loss-dependent and weight loss-independent alterations in multiple tissues (such as the intestine, liver, pancreas, adipose tissue and skeletal muscle) yield net improvements in insulin resistance, insulin secretion and insulin-independent glucose metabolism. In a subset of patients, post-bariatric hypoglycaemia can develop months to years after surgery, potentially reflecting the extreme effects of potent glucose reduction after surgery. This Review addresses the effects of bariatric surgery on glucose regulation and the potential mechanisms responsible for both the resolution of T2DM and the induction of hypoglycaemia.

The efficacy of GLP-1RAs for the management of postprandial hypoglycemia following bariatric surgery: a systematic review

OBJECTIVE

Postprandial hyperinsulinemic hypoglycemia with neuroglycopenia is an increasingly recognized complication of Roux-en-Y gastric bypass and gastric sleeve surgery that may detrimentally affect patient quality of life. One likely causal factor is glucagon-like peptide-1 (GLP-1), which has an exaggerated rise following ingestion of carbohydrates after bariatric surgery. This paper sought to assess the role of GLP-1 receptor agonists (GLP-1RAs) in managing postprandial hypoglycemia following bariatric surgery.

METHODS

MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, and Scopus were systematically and critically appraised for all peer-reviewed publications that suitably fulfilled the inclusion criteria established a priori. This systematic review was developed according to the Preferred Reporting Items for Systematic Review and Meta-Analyses Protocols (PRISMA-P). It followed methods outlined in the Cochrane Handbook for Systematic Reviews of Interventions and is registered with PROSPERO (International Prospective Register of Systematic Reviews; identifier CRD420212716429).

RESULTS AND CONCLUSIONS

Postprandial hyperinsulinemic hypoglycemia remains a notoriously difficult to manage metabolic complication of bariatric surgery. This first, to the authors' knowledge, systematic review presents evidence suggesting that use of GLP-1RAs does not lead to an increase of hypoglycemic episodes, and, although this approach may appear counterintuitive, the findings suggest that GLP-1RAs could reduce the number of postprandial hypoglycemic episodes and improve glycemic variability.

Medical Nutrition Therapy and Other Approaches to Management of Post-bariatric Hypoglycemia: A Team-Based Approach

PURPOSE OF REVIEW

This manuscript provides a review of post-bariatric hypoglycemia (PBH) with a special focus on the role of the registered dietitian-nutritionist (RDN) and medical nutrition therapy (MNT) recommendations as foundational for management.

RECENT FINDINGS

As the number of bariatric surgeries rises yearly, with 256,000 performed in 2019, PBH is an increasingly encountered late complication. Following Roux-en-Y (RYGB) or vertical sleeve gastrectomy (VSG), about 1/3 of patients report symptoms suggestive of at least mild postprandial hypoglycemia, with severe and/or medically confirmed hypoglycemia in 1-10%. Anatomical alterations, changes in GLP1 and other intestinally derived hormones, excessive insulin response, reduced insulin clearance, impaired counterregulatory hormone response to hypoglycemia, and other factors contribute to PBH. MNT is the cornerstone of multidisciplinary treatment, with utilization of personal continuous glucose monitoring to improve safety when possible. While many individuals require pharmacotherapy, there are no currently approved medications for PBH. Increasing awareness and identification of individuals at risk for or with PBH is critical given the potential impact on safety, nutrition, and quality of life. A team-based approach involving the individual, the RDN, and other clinicians is essential in providing ongoing assessment and individualization of MNT in the long-term management of PBH.

Combined laparoscopic Roux-en-Y gastric bypass reversal and gastric banding to treat severe hyperinsulinemic hypoglycemia: A case report and surgical video

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Non insulinoma pancreatogenous hypoglycemia syndrome is a recently described complication of Roux-en-Y gastric bypass

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Currently, there is no Gold Standard treatment.

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In this case, we successfully performed a combined laparoscopic reversal of gastric bypass and gastric banding

Pramlintide for post-bariatric hypoglycaemia

AIMS

The aim of this study was to examine the hypothesis that pramlintide would reduce hypoglycaemia by slowing gastric emptying and reducing postprandial glucagon secretion, thus limiting postprandial glycaemic excursions and insulin secretion, and thus to determine the efficacy of pramlintide on frequency and severity of hypoglycaemia in post-bariatric hypoglycaemia (PBH).

MATERIALS AND METHODS

Participants with PBH following gastric bypass were recruited from outpatient clinics at the Joslin Diabetes Center, Boston, Massachusetts for an open-label study of pramlintide efficacy over 8 weeks. Twenty-three participants were assessed for eligibility, 20 participants had at least one pramlintide dose, and 14 completed the study. A mixed-meal tolerance test (MMTT) was performed at baseline and after 8 weeks of subcutaneous pramlintide with a sequential dose increase to a maximum of 120 micrograms (mean 69 ± 32 mcg) three times daily. The primary endpoint was change in glucose excursions during the MMTT. Secondary measures included MMTT insulin response, satiety and dumping score, percentage time with sensor glucose (SG) <3.9 mM, and number of days with minimum SG <3 mM, during masked continuous glucose monitoring.

RESULTS

There were no differences in MMTT glucose, glucagon or insulin between baseline and post treatment. We observed no significant change in satiety or dumping scores. The overall frequency of low SG values did not change, although there was substantial inter-individual variability.

CONCLUSIONS

In PBH, pramlintide does not modulate glycaemic or insulin responses, satiety, or dumping scores during an MMTT and does not impact glycaemic excursions or decrease low SG levels in the outpatient setting.

Bariatric surgery and the liver-Mechanisms, benefits, and risks

The prevalence of obesity and metabolic diseases such as type 2 diabetes and nonalcoholic fatty liver disease (NAFLD) has risen dramatically over the past decades. At present, bariatric surgery is the most effective treatment for this global health problem, through effects on food intake, gut hormone secretion, metabolic signaling pathways, and adipose tissue dysfunction. The liver occupies a central role in carbohydrate, protein, and lipid metabolism. Notably, a reduction in hepatic fat content and an improvement in hepatic insulin resistance are among the earliest beneficial effects of bariatric surgery, which has therefore emerged as an attractive treatment option for NAFLD. However, as the scope and popularity of weight loss surgery have expanded, new questions have arisen regarding its safety in patients with liver cirrhosis, the outcome of liver transplantation in patients with a history of bariatric surgery, and over incidental reports of liver failure following surgery. Studies in humans and rodents have also linked bariatric surgery to an increased risk of developing alcohol use disorder, a major risk factor for liver disease. This review integrates data from clinical and translational research to delineate both the beneficial impact of bariatric surgery on the liver and the potential risks involved.

PREVENT: A Randomized, Placebo-controlled Crossover Trial of Avexitide for Treatment of Postbariatric Hypoglycemia

CONTEXT

Postbariatric hypoglycemia (PBH), characterized by enteroinsular axis overstimulation and hyperinsulinemic hypoglycemia, is a complication of bariatric surgery for which there is no approved therapy.

OBJECTIVE

To evaluate efficacy and safety of avexitide [exendin (9-39)], a glucagon-like peptide-1 antagonist, for treatment of PBH.

METHODS

A multicenter, Phase 2, randomized, placebo-controlled crossover study (PREVENT). Eighteen female patients with PBH were given placebo for 14 days followed by avexitide 30 mg twice daily and 60 mg once daily, each for 14 days in random order. The main outcome measures were glucose nadir and insulin peak during mixed-meal tolerance testing (MMTT) and hypoglycemic events captured by self-monitoring of blood glucose (SMBG), electronic diary, and blinded continuous glucose monitoring (CGM).

RESULTS

Compared with placebo, avexitide 30 mg twice daily and 60 mg once daily raised the glucose nadir by 21% (P = .001) and 26% (P = .0002) and lowered the insulin peak by 23% (P = .029) and 21% (P = .042), corresponding to 50% and 75% fewer participants requiring rescue during MMTT, respectively. Significant reductions in rates of Levels 1 to 3 hypoglycemia were observed, defined, respectively, as SMBG <70 mg/dL, SMBG <54 mg/dL, and a severe event characterized by altered mental and/or physical function requiring assistance. CGM demonstrated reductions in hypoglycemia without induction of clinically relevant hyperglycemia. Avexitide was well tolerated, with no increase in adverse events.

CONCLUSION

Avexitide administered for 28 days was well tolerated and resulted in robust and consistent improvements across multiple clinical and metabolic parameters, reinforcing the targeted therapeutic approach and demonstrating durability of effect. Avexitide may represent a first promising treatment for patients with severe PBH.

Do Gut Hormones Contribute to Weight Loss and Glycaemic Outcomes after Bariatric Surgery?

Bariatric surgery is an effective intervention for management of obesity through treating dysregulated appetite and achieving long-term weight loss maintenance. Moreover, significant changes in glucose homeostasis are observed after bariatric surgery including, in some cases, type 2 diabetes remission from the early postoperative period and postprandial hypoglycaemia. Levels of a number of gut hormones are dramatically increased from the early period after Roux-en-Y gastric bypass and sleeve gastrectomy—the two most commonly performed bariatric procedures—and they have been suggested as important mediators of the observed changes in eating behaviour and glucose homeostasis postoperatively. In this review, we summarise the current evidence from human studies on the alterations of gut hormones after bariatric surgery and their impact on clinical outcomes postoperatively. Studies which assess the role of gut hormones after bariatric surgery on food intake, hunger, satiety and glucose homeostasis through octreotide use (a non-specific inhibitor of gut hormone secretion) as well as with exendin 9–39 (a specific glucagon-like peptide-1 receptor antagonist) are reviewed. The potential use of gut hormones as biomarkers of successful outcomes of bariatric surgery is also evaluated.

The role of GLP-1 in postprandial glucose metabolism after bariatric surgery: a narrative review of human GLP-1 receptor antagonist studies

The Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) bariatric procedures lead to remission or improvement of type 2 diabetes. A weight loss-independent augmentation of postprandial insulin secretion contributes to the improvement in glycemic control after RYGB and is associated with a ∼10-fold increase in plasma concentrations of the incretin hormone glucagon-like peptide-1 (GLP-1). However, the physiologic importance of the markedly increased postprandial GLP-1 secretion after RYGB has been much debated. The effect of GLP-1 receptor blockade after RYGB has been investigated in 12 studies. The studies indicate a shift toward a more prominent role for GLP-1 in postprandial β-cell function after RYGB. The effect of GLP-1 receptor antagonism on glucose tolerance after RYGB is more complex and is associated with important methodological challenges. The postprandial GLP-1 response is less enhanced after SG compared with RYGB. However, the effect of GLP-1 receptor blockade after SG has been examined in 1 study only and needs further investigation.

Surgical Treatment for Postprandial Hypoglycemia After Roux-en-Y Gastric Bypass: a Literature Review

Roux-en-Y gastric bypass (RYGB) is an effective treatment for severe obesity and obesity-related comorbidities. Postprandial hypoglycemia may occur as a long-term complication after RYGB. This study reviews the literature on surgical treatment for intractable post-RYGB hypoglycemia to provide updated information. A search was performed in Embase and PubMed, and 25 papers were identified. Thirteen papers on reversal were included. Resolution of postprandial hypoglycemic symptoms occurred in 42/48 (88%) patients after reversal. Twelve papers on pancreatectomy were included. Resolution occurred in 27/50 (54%) patients after pancreatectomy. The optimal surgical treatment for intractable post-RYGB hypoglycemia has not been defined, but reversal of RYGB seems to be more effective than other treatments. Further research on etiology and long-term evaluation of surgical outcomes may refine treatment options.

Reversal to Normal Anatomy (With Sleeve Gastrectomy) for Severe Hypoglycemia

Background. Laparoscopic Roux-en-Y gastric bypass (GBP) is an essential bariatric surgical procedure which is globally performed because of the associated effective weight loss and resolution of metabolic comorbidities, such as diabetes and dyslipidemia. Although some complications may occur, hypoglycemia is a rare complication, which can lead to lethal consequences. We aimed to describe the technical aspects and surgical results after reversal to normal anatomy (RNA). Methods. We conducted a retrospective data analysis including 16 patients who underwent laparoscopic RNA from 2011 to 2018. All data were archived in a prospective database. Previous bariatric surgery and postoperative outcomes were analyzed. Results. Sixteen patients underwent RNA, most of them after GBP, and 15 patients required sleeve gastrectomy. Among them, 80% were women; 5 patients presented with postoperative complications, such as colitis with intra-abdominal collection (n = 1), gastric leak (n = 2) treated with an endoprosthesis, mesenteric venous thrombosis (n = 1), and intra-abdominal bleeding (n = 1). Mean length of hospital stay was 5.93 (3-30). All patients recovered from their initial condition although 3 patients presented with mild hypoglycemia during follow-up. Seven patients regained weight (43.75%), and another 4 developed gastroesophageal reflux disease (25%). Conclusions. These laparoscopic RNA results are acceptable, indicating a clinical improvement in the hypoglycemic syndrome in all patients.

Guidelines for gastrostomy tube placement and enteral nutrition in patients with severe, refractory hypoglycemia after gastric bypass

BACKGROUND

Postbariatric hypoglycemia (PBH) affects up to 38% of Roux-en-Y gastric bypass (RYGB) patients. Severe cases are refractory to diet and medications. Surgical treatments including bypass reversal and pancreatectomy are highly morbid and hypoglycemia often recurs. We have developed a highly effective method of treatment by which enteral nutrition administered through a gastrostomy (G) tube placed in the remnant stomach replaces oral diet: if done correctly this reverses hyperinsulinemia and hypoglycemia, yielding substantial health and quality of life benefits for severely affected patients.

OBJECTIVES

To provide clinical guidelines for placement of a G-tube to treat postRYGB hypoglycemia, including candidate selection, preoperative evaluation, surgical considerations, and post-RYGB management.

SETTING

Stanford University Hospital and Clinics.

METHODS

Based on our relatively large experience with placing and managing G-tubes for PBH treatment, an interdisciplinary task force developed guidelines for practitioners.

RESULTS

A team approach (endocrinologist, dietitian, surgeon, psychologist) is recommended. Appropriate candidates have a history of RYGB, severe hypoglycemia refractory to medical-nutrition therapy, and significantly affected quality of life. Preoperative requirements include education and expectation setting, determination of initial enteral feeding program, and establishing service with a home enteral provider. Close postoperative follow-up is needed to ensure success and may require adjustments in formula and mode/rate of delivery to optimize tolerance and meet nutritional goals. G-tube nutrition must fully replace oral nutrition to prevent hypoglycemia.

CONCLUSIONS

G-tube placement in the remnant stomach represents a relatively well-tolerated and effective treatment for severe, refractory hypoglycemia after RYGB.

Features of oral glucose tolerance tests in patients after Roux-en-Y gastric bypass with and without hypoglycaemia symptoms in daily life: It's all about speed

OBJECTIVE

To evaluate the glucose and insulin profiles during an oral glucose tolerance test (OGTT) after Roux-en-Y gastric bypass (RYGB) in symptomatic and asymptomatic patients.

RESEARCH DESIGN AND METHODS

This retrospective study consisted of two groups that had undergone RYGB. The symptomatic (S) group (n = 27) had an OGTT at presentation, whereas the asymptomatic (A) group (n = 99) had an OGTT 1 year after RYGB. Each group was subdivided into two groups, namely, those with glycaemia <54 mg/dL (S1/A1) and those with glycaemia >54 mg/dL (S2/A2) during OGTT. Most of the patients underwent OGTT preoperatively.

RESULTS

Preoperatively, the glucose and insulin levels, as well as the speed of increase and decrease, were similar in all groups. Postoperatively, the minimum glucose levels during the OGTT did not differ between the symptomatic and asymptomatic groups (55 ± 19 vs. 54 ± 17 mg/dL) or between the S1 and A1 subgroups (39 ± 7 vs. 43 ± 8 mg/dL). The peak glucose values were higher in the symptomatic versus the asymptomatic group (236 ± 52 vs. 189 ± 43 mg/dL; P <0.05) and in the S1 and S2 versus the A1 and A2 subgroups. The speed of glucose increase and decline was significantly higher in the symptomatic group versus the asymptomatic group, with the speed of glucose decline being the highest in the S1 subgroup.

CONCLUSION

Assessing hypoglycaemia after a gastric bypass remains challenging. Our study suggests that the main difference in glucose dynamics between symptomatic and asymptomatic patients might be the speed of glucose and insulin increase and decline during OGTT rather than the absolute values obtained.

Distal gastric mucosa ablation induces significant weight loss and improved glycemic control in type 2 diabetes Sprague-Dawley rat model

BACKGROUND

Excluding the foregut (distal stomach and duodenum) from food transit in RYGB normalizes glucose tolerance. Excluding/removing the duodenal mucosa partly improves glycemic control. So far, the effect of excluding/removing the gastric mucosa remains unknown.

OBJECTIVE

To observe the effect of removing the distal gastric mucosa on glucose tolerance.

METHOD

Thirty fatty Sprague-Dawley rats received low-dose streptozotocin (STZ) to induce type 2 diabetes (T2D), then randomly assigned to Roux-en-Y gastric bypass (RYGB, n = 8), distal gastric mucosa removal (DGMR, n = 8), duodenal-jejunal bypass (DJB, n = 8), and Sham (n = 6) groups. In the DGMR group, the distal third of the gastric mucosa was removed by thermal ablation using an electrocautery. Rats were followed for 8 weeks postoperatively. Preoperative oral glucose tolerance test (OGTT), insulin tolerance test (ITT), and mixed-meal tolerance test (MMTT) were repeated 3 and 6 weeks postoperatively. Changes in body weight, food intake, and fasting blood glucose were also recorded.

RESULTS

Gastrin AUC decreased significantly (p < 0.05) in the DGMR group after surgery. A significantly increased GLP-1 AUC was found in the RYGB, DGMR, and DJB groups at week 3 and only the RYGB group at week 6 postoperatively. The improved glucose tolerance in the RYGB group was significantly greater than the improved glucose tolerance in the DGMR and DJB groups. The improved glucose tolerance 3 and 6 weeks after surgery in the DGMR group was significantly greater than the improved glucose tolerance in the DJB group. Body weight decreased significantly in the RYGB, DGMR, and DJB groups postoperatively.

CONCLUSION

Removing the distal gastric mucosa induced significant weight loss and improved glycemic control in T2D SD rat model. Therefore, the gastric mucosa exclusion in RYGB may be key to the weight loss and diabetes remission, which perhaps warrants a new theory.

Reversal of Roux-en-Y Gastric Bypass Fails to Facilitate the Management of Recalcitrant Hypocalcaemia Caused by Primary Hypoparathyroidism

Roux-en-Y gastric bypass (RYGB) is thought to reduce calcium absorption from the gut. Here, we report the case of a patient with a RYGB, who developed primary hypoparathyroidism after a total thyroidectomy, leading to recalcitrant hypocalcaemia. Despite aggressive oral calcium and calcitriol supplementation, she remained hypocalcaemic and required intravenous (IV) calcium supplementation to control her symptoms, and to keep calcium serum levels within an acceptable range. Teriparatide treatment improved calcium levels marginally. This treatment, however, was poorly tolerated and ultimately stopped by the patient. As a last resort, reversal of RYGB was performed to improve calcium absorption from the gut. Unfortunately, IV calcium supplementation remained necessary. This case illustrates that the reversal of RYGB is not always a guarantee for success in managing recalcitrant hypocalcaemia.

Potential contribution of the gut microbiota to hypoglycemia after gastric bypass surgery

Obesity has become a global health problem. Lifestyle modification and medical treatment only appear to yield short-term weight loss. Roux-en-Y gastric bypass (RYGB) is the most popular bariatric procedure, and it sustains weight reduction and results in the remission of obesity-associated comorbidities for obese individuals. However, patients who undergo this surgery may develop hypoglycemia. To date, the diagnosis is challenging and the prevalence of post-RYGB hypoglycemia (PRH) is unclear. RYGB alters the anatomy of the upper gastrointestinal tract and has a combined effect of caloric intake restriction and nutrient malabsorption. Nevertheless, the physiologic changes after RYGB are complex. Although hyperinsulinemia, incretin effects, dysfunction of β-cells and α-cells, and some other factors have been widely investigated and are reported to be possible mediators of PRH, the pathogenesis is still not completely understood. In light of the important role of the gut microbiome in metabolism, we hypothesized that the gut microbiome might also be a critical link between RYGB and hypoglycemia. In this review, we mainly highlight the current possible factors predisposing individuals to PRH, particularly related to the gut microbiota, which may yield significant insights into the intestinal regulation of glucose metabolic homeostasis and provide novel clues to improve the treatment of type 2 diabetes mellitus.

Endoscopic management of dumping syndrome after Roux-en-Y gastric bypass: a large international series and proposed management strategy

BACKGROUND AND AIMS

Roux-en-Y gastric bypass (RYGB) is refractory to lifestyle and pharmacotherapy measures, requiring reversal of the patient's bariatric surgery. Reversal can lead to weight regain and recrudescence of their comorbidities. Our aim was to report a multicenter experience on the endoscopic management of refractory dumping syndrome with endoscopic transoral outlet reduction (TORe).

METHODS

A multicenter international series of consecutive patients who underwent TORe with a full-thickness endoscopic suturing device was analyzed for technical success, improvement in Sigstad scores, and weight trajectories after the procedure. Failure was defined as needing an enteral feeding tube, surgical reversal, or repeat TORe.

RESULTS

One hundred fifteen patients across 2 large academic centers in Germany and the United States underwent TORe for dumping syndrome. Patient age was mean 8.9 ± 1.1 years from their initial RYGB with an average percent total body weight loss of 31% ± 10.6% at the time of endoscopy. Three months postprocedure, the Sigstad score improved from a mean of 17 ± 6.1 to 2.6 ± 1.9 (paired t test P = .0001) with only 2% of patients (n = 2) experiencing weight gain. Mean weight loss and percentage of total body weight loss 3 months post-TORe were 9.47 ± 3.6 kg and 9.47% ± 2.5%, respectively. Six patients (5%) failed initial endoscopic therapy, with 50% (n = 3) successfully treated with a repeat TORe. Three patients underwent surgical reversal, indicating an overall 97% endoscopic success rate.

CONCLUSIONS

TORe as an adjunct to lifestyle and pharmacologic therapy for refractory dumping syndrome is safe and effective at improving dumping syndrome and reducing rates of surgical revision.

Common and Rare Complications of Bariatric Surgery

As the prevalence of obesity has increased, bariatric surgery has become more common because of its proven efficacy at promoting weight loss and improving weight-related medical comorbidities. Although generally successful, bariatric surgery may also lead to complications and negatively affect health. This article highlights some common and rare complications of bariatric surgery. Specifically, it discusses the risk of nutrient deficiencies (which is influenced by surgery type) and their downstream effects, including ill-effects on bone health. Rarer complications, such as postbypass hypoglycemia and alcohol use disorder, are also discussed.

Hypoglycemia After Upper Gastrointestinal Surgery: Clinical Approach to Assessment, Diagnosis, and Treatment

CONTEXT

Post-bariatric hypoglycemia (PBH) is an increasingly encountered complication of upper gastrointestinal surgery; the prevalence of this condition is anticipated to rise given yearly increases in bariatric surgical procedures. While PBH is incompletely understood, there is a growing body of research describing the associated factors, mechanisms, and treatment approaches for this condition.

EVIDENCE ACQUISITION

Data are integrated and summarized from studies of individuals affected by PBH and hypoglycemia following upper gastrointestinal surgery obtained from PubMed searches (1990-2020).

EVIDENCE SYNTHESIS

Information addressing etiology, incidence/prevalence, clinical characteristics, assessment, and treatment were reviewed and synthesized for the practicing physician. Literature reports were supplemented by clinical experience as indicated, when published data were not available.

CONCLUSION

PBH can be life-altering and severe for a subset of individuals. Given the chronic nature of this condition, and sequelae of both acute and recurrent episodes, increasing provider awareness of both the condition and associated risk factors is critical for assessment, prompt diagnosis, treatment, and preoperative identification of individuals at risk.

The Effects of Bariatric Surgery on Islet Function, Insulin Secretion, and Glucose Control

Although bariatric surgery was developed primarily to treat morbid obesity, evidence from the earliest clinical observations to the most recent clinical trials consistently demonstrates that these procedures have substantial effects on glucose metabolism. A large base of research indicates that bariatric surgeries such as Roux-en-Y gastric bypass (RYGB), vertical sleeve gastrectomy (VSG), and biliopancreatic diversion (BPD) improve diabetes in most patients, with effects frequently evident prior to substantial weight reduction. There is now unequivocal evidence from randomized controlled trials that the efficacy of surgery is superior to intensive life-style/medical management. Despite advances in the clinical understanding and application of bariatric surgery, there remains only limited knowledge of the mechanisms by which these procedures confer such large changes to metabolic physiology. The improvement of insulin sensitivity that occurs with weight loss (e.g., the result of diet, illness, physical training) also accompanies bariatric surgery. However, there is evidence to support specific effects of surgery on insulin clearance, hepatic glucose production, and islet function. Understanding the mechanisms by which surgery affects these parameters of glucose regulation has the potential to identify new targets for therapeutic discovery. Studies to distinguish among bariatric surgeries on key parameters of glucose metabolism are limited but would be of considerable value to assist clinicians in selecting specific procedures and investigators in delineating the resulting physiology. This review is based on literature related to factors governing glucose metabolism and insulin secretion after the commonly used RYGB and VSG, and the less frequently used BPD and adjustable gastric banding.

Postprandial hypoglycemia after gastric bypass surgery: from pathogenesis to diagnosis and treatment

PURPOSE OF REVIEW

The Roux-en-Y gastric bypass surgery (RYGB) improves glucose control in majority of patients with type 2 diabetes. However, a minority group of individuals develop a life-threatening complication of hyperinsulinemic hypoglycemia. The goal of this review is to identify underlying mechanisms by which RYGB cause hypoglycemia and describe pathogenesis-driven strategies to diagnose and treat this condition.

RECENT FINDINGS

Gastric bypass leads to higher and earlier peak levels of glucose and lower nadir glucose after eating along with larger insulin and glucagon-like peptide 1 (GLP-1) secretion, resetting the balance between glucose appearance and clearance after this procedure. These weight-loss independent glycemic effects of RYGB have been attributed to changes in ingested glucose appearance as a result of rapid nutrient emptying from stomach pouch to the intestine and increased glucose clearance as a result of prandial hyperinsulinemia. The exaggerated effect of RYGB on postmeal glucose metabolism is a syndrome of postprandial hyperinsulinemic hypoglycemia manifesting in a group of individuals several years after this surgery. Affected patients have larger systemic appearance of ingested glucose and greater postmeal secretion of insulin and GLP-1 compared to those with history of RYGB without symptomatic hypoglycemia. Current evidence supporting a multifactorial model of glucose dysregulation among patients with hypoglycemia will be highlighted in this review.

SUMMARY

Hypoglycemia after RYGB is a life-threatening condition and likely represents the extreme glycemic phenotype of this procedure. Diagnosis is challenging and treatment options are limited.

Weight-Independent Mechanisms of Glucose Control After Roux-en-Y Gastric Bypass

Roux-en-Y gastric bypass results in large and sustained weight loss and resolution of type 2 diabetes in 60% of cases at 1-2 years. In addition to calorie restriction and weight loss, various gastro-intestinal mediated mechanisms, independent of weight loss, also contribute to glucose control. The anatomical re-arrangement of the small intestine after gastric bypass results in accelerated nutrient transit, enhances the release of post-prandial gut hormones incretins and of insulin, alters the metabolism and the entero-hepatic cycle of bile acids, modifies intestinal glucose uptake and metabolism, and alters the composition and function of the microbiome. The amelioration of beta cell function after gastric bypass in individuals with type 2 diabetes requires enteric stimulation. However, beta cell function in response to intravenous glucose stimulus remains severely impaired, even in individuals in full clinical diabetes remission. The permanent impairment of the beta cell may explain diabetes relapse years after surgery.

Hypoglycemia After Gastric Bypass Surgery: Current Concepts and Controversies

CONTEXT

Hypoglycemia, occurring after bariatric and other forms of upper gastrointestinal surgery, is increasingly encountered by clinical endocrinologists. The true frequency of this condition remains uncertain, due, in part, to differences in the diagnostic criteria and in the affected populations, as well as relative lack of patient and physician awareness and understanding of this condition. Postbariatric hypoglycemia can be severe and disabling for some patients, with neuroglycopenia (altered cognition, seizures, and loss of consciousness) leading to falls, motor vehicle accidents, and job and income loss. Moreover, repeated episodes of hypoglycemia can result in hypoglycemia unawareness, further impairing safety and requiring the assistance of others to treat hypoglycemia.

OBJECTIVE

In this review, we summarize and integrate data from studies of patients affected by hypoglycemia after Roux-en-Y gastric bypass (RYGB) surgery, obtained from PubMed searches (1990 to 2017) and reference searches of relevant retrieved articles. Whereas hypoglycemia can also be observed after sleeve gastrectomy and fundoplication, this review is focused on post-RYGB, given the greater body of published clinical studies at present.

OUTCOME MEASURES

Data addressing specific aspects of diagnosis, pathophysiology, and treatment were reviewed by the authors; when not available, the authors have provided opinions based on clinical experience with this challenging condition.

CONCLUSIONS

Hypoglycemia, occurring after gastric bypass surgery, is challenging for patients and physicians alike. This review provides a systematic approach to diagnosis and treatment based on the underlying pathophysiology.

Dissecting the Physiology and Pathophysiology of Glucagon-Like Peptide-1

An aging world population exposed to a sedentary life style is currently plagued by chronic metabolic diseases, such as type-2 diabetes, that are spreading worldwide at an unprecedented rate. One of the most promising pharmacological approaches for the management of type 2 diabetes takes advantage of the peptide hormone glucagon-like peptide-1 (GLP-1) under the form of protease resistant mimetics, and DPP-IV inhibitors. Despite the improved quality of life, long-term treatments with these new classes of drugs are riddled with serious and life-threatening side-effects, with no overall cure of the disease. New evidence is shedding more light over the complex physiology of GLP-1 in health and metabolic diseases. Herein, we discuss the most recent advancements in the biology of gut receptors known to induce the secretion of GLP-1, to bridge the multiple gaps into our understanding of its physiology and pathology.