GLP1 analogs as treatment of postprandial hypoglycemia following gastric bypass surgery: a potential new indication?

The Impact of Cholecystectomy in Patients with Post-Bariatric Surgery Hypoglycemia

BACKGROUND

Metabolic surgery is the foremost treatment for obesity and its associated medical conditions. Nonetheless, post-bariatric hypoglycemia (PBH) emerges as a prevalent complication. PBH pathophysiology implicates heightened insulin and glucagon-like peptide 1 (GLP-1) levels, with bile acids (BA) contributing to GLP-1 release. A plausible association exists between cholecystectomy and PBH, which is attributed to alterations in BA metabolism and ensuing hormonal responses. The objective of this retrospective cohort study was to evaluate the impact of cholecystectomy on PBH pharmacological treatment, diagnostic timelines and metabolic parameters.

MATERIALS AND METHODS

Patients diagnosed with PBH after bariatric surgery were evaluated based on their history of cholecystectomy. Demographic, anthropometric and clinical data were collected. Mixed meal tolerance tests (MMTT) results were compiled to assess metabolic responses.

RESULTS

Of the 131 patients with PBH included in the study, 29 had prior cholecystectomy. The time to PBH diagnosis was similar across groups. Patients with prior cholecystectomy required higher doses of acarbose (p = 0.046), compared to those without prior cholecystectomy. Additionally, MMTT revealed higher insulin (t = 60 min: p = 0.010 and t = 90 min: p = 0.034) and c-peptide levels (t = 60 min: p = 0.008) and greater glycemic variability in patients with prior cholecystectomy (p = 0.049), highlighting the impact of cholecystectomy on glucose metabolism.

CONCLUSION

Our study offers novel insights into PBH pharmacotherapy, indicating that PBH patients with a history of cholecystectomy require elevated doses of acarbose for symptom control than PBH patients without such surgical history. Furthermore, our findings underscore the pivotal role of hyperinsulinism in PBH aetiology, emphasizing the significance of the BA-GLP-1-insulin axis.

Hypoglycemia Unawareness-A Review on Pathophysiology and Clinical Implications

Hypoglycemia is a particular problem in people with diabetes while it can also occur in other clinical circumstances. Hypoglycemia unawareness describes a condition in which autonomic and neuroglycopenic symptoms of hypoglycemia decrease and hence are hardly perceivable. A failure to recognize hypoglycemia in time can lead to unconsciousness, seizure, and even death. The risk factors include intensive glycemic control, prior episodes of severe hypoglycemia, long duration of diabetes, alcohol consumption, exercise, renal failure, and sepsis. The pathophysiological mechanisms are manifold, but mainly concern altered brain glucose sensing, cerebral adaptations, and an impaired hormonal counterregulation with an attenuated release of glucagon, epinephrine, growth hormone, and other hormones, as well as impaired autonomous and neuroglycopenic symptoms. Physiologically, this counterregulatory response causes blood glucose levels to rise. The impaired hormonal counterregulatory response to recurrent hypoglycemia can lead to a vicious cycle of frequent and poorly recognized hypoglycemic episodes. There is a shift in glycemic threshold to trigger hormonal counterregulation, resulting in hypoglycemia-associated autonomic failure and leading to the clinical syndrome of hypoglycemia unawareness. This clinical syndrome represents a particularly great challenge in diabetes treatment and, thus, prevention of hypoglycemia is crucial in diabetes management. This mini-review provides an overview of hypoglycemia and the associated severe complication of impaired hypoglycemia awareness and its symptoms, pathophysiology, risk factors, consequences, as well as therapeutic strategies.

Proposed treatment strategy for reactive hypoglycaemia

Background/aim

Managing reactive hypoglycaemia (RH) poses challenges due to limited and often ineffective treatment options. We report a case series and draw on this to propose a stepwise treatment approach consisting of lifestyle modifications, metformin, GLP-1 analogues, and the use of flash glucose monitoring technology.

Method

A retrospective review was conducted to analyse the management of 11 cases presenting with recurrent RH symptoms.

Result

Two patients experienced successful resolution of symptoms through lifestyle modifications. Metformin alone was effective in treating seven out of nine patients who received pharmacological treatment. Two patients with previous upper gastrointestinal surgery showed a partial response to metformin and benefited further from additional long-acting GLP-1 analogue. Pharmacological intervention led to significant reductions in insulin and C-peptide levels in repeat mixed meal tolerance tests (P-values 0.043 for insulin and 0.006 for C-peptide). Finally, flash glucose monitoring technology was useful in early detection and preventing episodes of hypoglycaemia in one of these patients with persistent symptoms.

Conclusion

These findings highlight the potential efficacy of escalated treatment strategies for RH, including the use of metformin, GLP-1 analogues, and flash glucose monitoring technology.

Postprandial plasma GLP-1 levels are elevated in individuals with postprandial hypoglycaemia following Roux-en-Y gastric bypass - a systematic review

BACKGROUND AND AIMS

Bariatric surgery is the most effective treatment in individuals with obesity to achieve remission of type 2 diabetes. Post-bariatric surgery hypoglycaemia occurs frequently, and management remains suboptimal, because of a poor understanding of the underlying pathophysiology. The glucoregulatory hormone responses to nutrients in individuals with and without post-bariatric surgery hypoglycaemia have not been systematically examined.

MATERIALS AND METHODS

The study protocol was prospectively registered with PROSPERO. PubMed, EMBASE, Web of Science and the Cochrane databases were searched for publications between January 1990 and November 2021 using MeSH terms related to post-bariatric surgery hypoglycaemia. Studies were included if they evaluated individuals with post-bariatric surgery hypoglycaemia and included measurements of plasma glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), insulin, C-peptide and/or glucagon concentrations following an ingested nutrient load. Glycated haemoglobin (HbA1c) was also evaluated. A random-effects meta-analysis was performed, and Hedges' g (standardised mean difference) and 95% confidence intervals were reported for all outcomes where sufficient studies were available. The τ2 estimate and I2 statistic were used as tests for heterogeneity and a funnel plot with the Egger regression-based test was used to evaluate for publication bias.

RESULTS

From 377 identified publications, 12 were included in the analysis. In all 12 studies, the type of bariatric surgery was Roux-en-Y gastric bypass (RYGB). Comparing individuals with and without post-bariatric surgery hypoglycaemia following an ingested nutrient load, the standardised mean difference in peak GLP-1 was 0.57 (95% CI, 0.32, 0.82), peak GIP 0.05 (-0.26, 0.36), peak insulin 0.84 (0.44, 1.23), peak C-peptide 0.69 (0.28, 1.1) and peak glucagon 0.05 (-0.26, 0.36). HbA1c was less in individuals with hypoglycaemia - 0.40 (-0.67, -0.12). There was no evidence of substantial heterogeneity in any outcome except for peak insulin: τ2 = 0.2, I2 = 54.3. No publication bias was evident.

CONCLUSION

Following RYGB, postprandial peak plasma GLP-1, insulin and C-peptide concentrations are greater in individuals with post-bariatric surgery hypoglycaemia, while HbA1c is less. These observations support the concept that antagonism of GLP-1 would prove beneficial in the management of individuals with hypoglycaemia following RYGB.PROSPERO Registration Number: CRD42021287515.

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.

Medical and surgical treatment of postbariatric hypoglycaemia: Retrospective data from daily practice

AIM

To evaluate medical and surgical treatment of postbariatric hypoglycaemia (PBH) in daily practice.

MATERIALS AND METHODS

Retrospective data were extracted from medical records from four hospitals. PBH was defined by neuroglycopenic symptoms together with a documented glucose <3.0 mmol/L in the postprandial setting after previous bariatric surgery. Data were scored semiquantitatively on efficacy and side effects by two reviewers independently. Duration of efficacy and of use were calculated.

RESULTS

In total, 120 patients were included with a median follow-up of 27 months with a mean baseline age of 41 years, total weight loss of 33% and glucose nadir 2.3 mmol/L. Pharmacotherapy consisted of acarbose, diazoxide, short- and long-acting octreotide and glucagon-like peptide-1 receptor agonist analogues (liraglutide and semaglutide) with an overall efficacy in 45%-75% of patients. Combination therapy with two drugs was used by 30 (25%) patients. The addition of a second drug was successful in over half of the patients. Long-acting octreotide and the glucagon-like peptide-1 receptor agonist analogues scored best in terms of efficacy and side effects with a median duration of use of 35 months for octreotide. Finally, 23 (19%) patients were referred for surgical intervention. Efficacy of the surgical procedures, pouch banding, G-tube placement in remnant stomach and Roux-en-Y gastric bypass reversal, pooled together, was 79% with a median duration of initial effect of 13 months.

CONCLUSIONS

In daily practice, pharmacotherapy for PBH was successful in half to three quarters of patients. Combination therapy was often of value. One in five patients finally needed a surgical procedure, with overall good results.

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.

Therapeutic Potential of GLP-2 Analogs in Gastrointestinal Disorders: Current Knowledge, Nutritional Aspects, and Future Perspectives

PURPOSE OF REVIEW

Although Glucagon-like peptide (GLP)-1 receptor agonists have been used for almost two decades in the treatment of diabetes mellitus type 2 and, lately, in obesity, recent years have seen an increasing interest in the pharmacological agonism of other proglucagon-derived peptides, including GLP-2. Herein, we aimed to review the available evidence on the effects of GLP-2 agonism from animal and clinical studies. Furthermore, we summarize the current clinical applications of GLP-2 agonists among patients with intestinal failure associated with short bowel syndrome (SBS-IF) as well as potential future expansion of their indications to other intestinal disorders.

RECENT FINDINGS

Evidence from preclinical studies has highlighted the cellular trophic and functional beneficial actions of GLP-2 on small intestinal and colonic mucosa. Subsequently, pharmacologic agonism of GLP-2 has gathered interest for the treatment of patients with conditions pertaining to the loss of intestinal anatomical and/or functional integrity to a degree requiring parenteral support, collectively referred to as intestinal failure. GLP-2 analogs positively influence nutrient absorption in animal models and humans, although continued therapy is likely needed for sustained effects. The degradation-resistant GLP-2-analog teduglutide has received approval for the treatment of SBS-IF, in which it may decisively reduce patient dependency on parenteral support and improve quality of life. Another two longer-acting analogs, glepaglutide and apraglutide, are currently undergoing phase III clinical trials. The use of GLP-2 analogs is effective in the management of SBS-IF and may show promise in the treatment of other severe gastrointestinal disorders associated with loss of effective intestinal resorptive surface area.

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.

Recommendations for the diagnosis and treatment of hypoglycaemia after bariatric surgery

Postprandial hyperinsulinaemic hypoglycaemia is a common complication of bariatric surgery. Although in general its evolution is mild and self-limited, it can lead to neuroglycopaenia and compromise the patient's safety and quality of life. The aim of this document is to offer some recommendations to facilitate the clinical care of these complex patients, reviewing the aetiopathogenesis, its diagnosis and treatment that, sequentially, will include dietary and pharmacological measures and surgery in refractory cases. In the absence of high-quality studies, the diagnostic and therapeutic approach proposed is based on the consensus of experts of the Grupo de Obesidad de la Sociedad Española de Endocrinología y Nutrición [Obesity Group of the Spanish Society of Endocrinology and Nutrition], GOSEEN. Those undergoing bariatric surgery should be informed of the possibility of developing this complication.

Dasiglucagon Effectively Mitigates Postbariatric Postprandial Hypoglycemia: A Randomized, Double-Blind, Placebo-Controlled, Crossover Trial

OBJECTIVE

To investigate the efficacy and safety of dasiglucagon, a novel stable glucagon analog in a liquid formulation, in Roux-en-Y gastric bypass (RYGB)-operated individuals suffering from postbariatric hypoglycemia (PBH).

RESEARCH DESIGN AND METHODS

In a randomized, double-blind, placebo-controlled, crossover trial, 10 RYGB-operated participants with continuous glucose monitoring-verified PBH were randomly assigned to 3 trial days, each consisting of a 240-min standardized liquid mixed-meal test with the subcutaneous injection of placebo or 80 μg or 200 μg dasiglucagon.

RESULTS

Compared with placebo, treatment with both 80 and 200 μg dasiglucagon raised nadir plasma glucose (PG) (placebo: 3.0 ± 0.2 mmol/L [mean ± SEM]; 80 μg dasiglucagon: 3.9 ± 0.3 mmol/L, P = 0.002; 200 μg dasiglucagon: 4.5 ± 0.2 mmol/L, P = 0.0002) and reduced time in hypoglycemia (PG <3.9 mmol/L) by 70.0 min (P = 0.030 and P = 0.008).

CONCLUSIONS

Single-dose administration of dasiglucagon effectively mitigated postprandial hypoglycemia.

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.

[Postoperative dumping-syndrome with relevant impairment of glucose homeostasis - relief by continuous glucose monitoring and individual therapy with GLP-1 receptor agonists]

Dumping syndromes are a common side effect after partial or total gastric resection. The symptoms may be diverse, with vasomotoric reactions, collapse tendencies and digestive disorders (early dumping) as well as blood sugar derailment as a result of too fast absorption of glucose (late dumping).Entrenched therapy concepts, including personalized nutritional concepts and the use of medication as octreotide or diazoxide, will not always lead to the desired results. It is then, that individual therapy concepts have to be found to restore the patient's quality of life, as shown in this case study.

Incidence of Dumping Syndrome after Sleeve Gastrectomy, Roux-en-Y Gastric Bypass and One-Anastomosis Gastric Bypass

PURPOSE

Dumping syndrome (DS) is an important but often underreported problem occurring after bariatric surgery. It is believed that gastric bypass procedures like Roux-en-Y Gastric By-pass (RYGB) and One-Anastomosis Gastric Bypass (OAGB) are more likely to cause DS than the pylorus-preserving Sleeve Gastrectomy (SG). The aim of this study was to evaluate the incidence of DS in patients undergoing SG, RYGB and OAGB.

MATERIALS AND METHODS

A retrospective clinical study with 180 patients undergoing SG (n=50), RYGB (n=53) and OAGB (n=77) between 2016-2018 was performed. All clinical and demo-graphic data were assessed. The percentage of excess weight loss (%EWL) was used to evaluate weight reduction. 127/180 (70.6%) patients took part in an additional phone interview. The incidence of DS was evaluated using validated Sigstad Score.

RESULTS

Information about the occurrence of dumping symptoms and patient satisfaction was obtained from 127 patients. Median follow-up was 20.0±11.4 months. Significant differences between the surgical procedures were found for the duration of surgery, complications, weight loss, incidence of DS and satisfaction postoperatively. DS occurred in 15.6% after SG, 56.4% after RYGB and 42.9% after OAGB. A higher weight loss was observed in patients who experienced dumping symptoms.

CONCLUSION

The present results show a clear superiority of SG regarding both perioperative results and incidence of DS compared to RYGB and OAGB and may impact clinicians and patients in their choice of procedure.

Unklare Lymphadenopathie mit Panzytopenie bei einer Patientin mit rezidivierenden Hypoglykämien

Eine Patientin wurde aufgrund rezidivierender postprandialer Hypoglykämien nach Roux-en-Y-Magenbypass mit Diazoxid behandelt, nachdem eine Ernährungsumstellung keine Symptomlinderung erzielt hatte. Nach Eindosierung von Diazoxid mit guter Akutverträglichkeit wurde die Patientin entlassen. Eine Woche nach Therapieeinleitung kam es zu einer Lymphadenopathie und Panzytopenie. Es fanden sich keine Hinweise auf das Vorliegen eines Infekts. Nach Absetzen von Diazoxid sistierten die Beschwerden. Unser Fallbericht weist auf seltene unerwünschte hämatologische Arzneimittelwirkungen unter Diazoxid hin.

Effectiveness of beinaglutide in a patient with late dumping syndrome after gastrectomy: A case report

RATIONALE

Dumping syndrome is a frequent and potentially severe complication after gastric surgery. Beinaglutide, a recombinant human glucagon-like peptide-1 (GLP-1) which shares 100% homology with human GLP-1(7-36), has never been reported in the treatment of dumping syndrome before.

PATIENT CONCERNS

The patient had undergone distal gastrectomy for gastric signet ring cell carcinoma 16 months ago. He presented with symptoms of paroxysmal palpitation, sweating, and dizziness for 4 months.

DIAGNOSIS

He was diagnosed with late dumping syndrome.

INTERVENTIONS AND OUTCOMES

The patient was treated with dietary changes and acarbose for 4 months before admitted to our hospital. The treatment with dietary changes and acarbose did not prevent postprandial hyperinsulinemia and hypoglycemia according to the 75 g oral glucose tolerance test (OGTT) and continuous glucose monitoring (CGM) on admission.Therefore, the patient was treated with beinaglutide 0.1 mg before breakfast and lunch instead of acarbose. After the treatment of beinaglutide for 1 month, OGTT showed a reduction in postprandial hyperinsulinemia compared with before starting treatment, and the time in the range of 3.9 to 10 mmol/L became 100% in CGM. No side effect was observed in this patient during beinaglutide treatment.

LESSONS

These findings suggest that beinaglutide may be effective for treating post-gastrectomy late dumping syndrome.

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.

Approach to the Patient: Management of the Post-Bariatric Surgery Patient With Weight Regain

CONTEXT

Weight regain (WR) after bariatric surgery is emerging as a common clinical problem due to the increase in the number of procedures performed. Early interventions are necessary to curtail the potential recurrence of comorbid conditions. However, it is often difficult to recognize WR early enough to introduce mitigating measures because there are no current guidelines for timely diagnosis and assessment of the severity of this condition.

OBJECTIVE

We present a practical approach for the early recognition of WR, based on 11-year follow-up data from our multiethnic bariatric surgery patient population.

METHODS

We classify WR according to the rate of increase in weight relative to nadir weight, normalized per 30-day interval. We also review pertinent literature about the etiologic factors contributing to WR after bariatric surgery.

RESULTS

According to our algorithm, mild, moderate, and rapid WR are defined as weight increases of 0.2% to <0.5%, 0.5% to 1.0%, and more than 1.0% of nadir weight per 30 days, respectively. Treatment options, including dietary counseling, use of antiobesity medication, and consideration of surgical revision, are described. A case is presented to illustrate the utility of timely identification of WR and the importance of collaboration between bariatric surgeons, obesity medicine specialists, and dietitians.

CONCLUSION

Our approach emphasizes the importance of regular long-term follow-up for all bariatric surgery 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.

Counterregulatory responses to postprandial hypoglycemia after Roux-en-Y gastric bypass

BACKGROUND

Postbariatric hypoglycemia (PBH) is a potentially serious complication after Roux-en-Y gastric bypass (RYGB), and impaired counterregulatory hormone responses have been suggested to contribute to the condition.

OBJECTIVES

We evaluated counterregulatory responses during postprandial hypoglycemia in individuals with PBH who underwent RYGB.

SETTING

University hospital.

METHODS

Eleven women with documented PBH who had RYGB underwent a baseline liquid mixed meal test (MMT) followed by 5 MMTs preceded by treatment with (1) acarbose 50 mg, (2) sitagliptin 100 mg, (3) verapamil 120 mg, (4) liraglutide 1.2 mg, and (5) pasireotide 300 μg. Blood was collected at fixed time intervals. Plasma and serum were analyzed for glucose, insulin, glucagon, epinephrine, norepinephrine, pancreatic polypeptide (PP), and cortisol.

RESULTS

During the baseline MMT, participants had nadir blood glucose concentrations of 3.3 ± .2 mmol/L. At the time of nadir glucose, there was a small but significant increase in plasma glucagon. Plasma epinephrine concentrations were not increased at nadir glucose but were significantly elevated by the end of the MMT. There were no changes in norepinephrine, PP, and cortisol concentrations in response to hypoglycemia. After treatment with sitagliptin, 8 individuals had glucose nadirs <3.2 mmol/L (versus 4 individuals at baseline), and significant increases in glucagon, PP, and cortisol responses were observed.

CONCLUSIONS

In response to postprandial hypoglycemia, individuals with PBH who underwent RYGB only had minor increases in counterregulatory hormones, while larger hormone responses occurred when glucose levels were lowered during treatment with sitagliptin. The glycemic threshold for counterregulatory activation could be altered in individuals with PBH, possibly explained by recurrent hypoglycemia.

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.

Safety, efficacy and pharmacokinetics of repeat subcutaneous dosing of avexitide (exendin 9-39) for treatment of post-bariatric hypoglycaemia

AIM

To evaluate the safety, efficacy and pharmacokinetics of repeat dosing of two formulations of subcutaneous (SC) avexitide (exendin 9-39) in patients with post-bariatric hypoglycaemia (PBH).

METHODS

In this phase 2, multiple-ascending-dose study conducted at Stanford University, 19 women with PBH underwent a baseline oral glucose tolerance test (OGTT), with metabolic and symptomatic assessments. Fourteen were then sequentially assigned to receive one of four ascending-dose levels of twice-daily lyophilized (Lyo) avexitide by SC injection for 3 days. On the basis of safety, efficacy and tolerability, five additional participants then received a novel liquid formulation (Liq) of avexitide by SC injection at a fixed dose of 30 mg twice daily for 3 days. All 19 participants underwent a repeat OGTT on day 3 of dosing to quantify metabolic, symptomatic and pharmacokinetic responses.

RESULTS

Treatment with Lyo avexitide reduced the magnitude of symptomatic hyperinsulinaemic hypoglycaemia at all dose levels, with dose-dependent improvements in glucose nadir, insulin peak and symptom score; doses ≥20 mg twice daily did not require glycaemic rescue (administered at glucose <2.8 mmol/L). Participants receiving Liq avexitide 30 mg twice daily did not require any glycaemic rescue, and on average achieved a 47% increase in glucose nadir, a 67% reduction in peak insulin, and a 47% reduction in overall symptom score. Equivalent doses of Liq versus Lyo avexitide yielded higher and more sustained plasma concentrations. Both formulations were well tolerated.

CONCLUSIONS

In patients with PBH, twice-daily administration of SC avexitide effectively raised the glucose nadir and prevented severe hypoglycaemia requiring rescue intervention. Avexitide may represent a viable therapy for PBH.

Hyperinsulinemic Hypoglycemia after Bariatric Surgery

Postprandial hyperinsulinemic hypoglycemia (PHH) is one of the serious complications after bariatric surgery, it can lead life-threatening neuroglycopenic symptoms, such as seizures, disorientation, impairment of version and loss of consciousness without any premonitory. The presentation, prevalence, diagnosis, pathology and treatment are reviewed in this summary.

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.

Brunner's Gland Hyperplasia in a Patient after Roux-Y Gastric Bypass: An Important Pitfall in GLP-1 Receptor Imaging

Severe cases of postprandial hypoglycaemia after bariatric surgery can be a diagnostic and therapeutic challenge. The diagnostic role of ⁶⁸Ga-DOTA-Exendin-4 PET/CT in postbariatric hypoglycaemia for further treatment decisions is unclear. We present a case of a 50-year-old woman with frequent and severe postprandial hypoglycaemic (≤2.5 mmol/L) episodes starting three years after Roux-Y gastric bypass. Despite strict dietary adherence and several medical therapies, the patient remained severely affected, and ⁶⁸Ga-DOTA-Exendin-4 PET/CT was performed to exclude atypical presentation of an insulinoma or nesidioblastosis. No pancreatic abnormalities were found, but intensive tracer accumulation in the first and second part of the duodenum was detected, which proved to be hyperplastic Brunner's glands on histology and were strongly positive for the glucagon-like peptide-1 receptor. This case provides histopathological verification that duodenal ⁶⁸Ga-DOTA-Exendin-4 uptake is caused by uptake in Brunner's glands and points to a potential relationship between bariatric surgery and Brunner's glands.

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 hypoglycaemia after Roux-en-Y gastric bypass and the effects of acarbose, sitagliptin, verapamil, liraglutide and pasireotide

AIM

To investigate the effects of acarbose, sitagliptin, verapamil, liraglutide and pasireotide on post-bariatric hypoglycaemia (PBH) after Roux-en-Y gastric bypass.

MATERIALS AND METHODS

In a randomized crossover study, 11 women who had undergone Roux-en-Y gastric bypass and had documented hypoglycaemia were each evaluated during a baseline period without treatment and during five treatment periods with the following interventions: acarbose 50 mg for 1 week, sitagliptin 100 mg for 1 week, verapamil 120 mg for 1 week, liraglutide 1.2 mg for 3 weeks and pasireotide 300 μg as a single dose. Treatment effects were evaluated by a mixed-meal tolerance test (MMTT) and, for all treatment periods except pasireotide, by 6 days of continuous glucose monitoring (CGM).

RESULTS

Treatment with acarbose and treatment with pasireotide both significantly lifted nadir glucose levels (mean ± SEM 3.9 ± 0.2 and 7.9 ± 0.4 vs 3.4 ± 0.2; P < .03) and reduced time in hypoglycaemia during the MMTTs. Acarbose reduced peak glucose levels and time in hyperglycaemia, whereas pasireotide greatly increased both variables. Acarbose and pasireotide reduced insulin and C-peptide levels, and pasireotide also diminished glucagon-like peptide-1 levels. Sitagliptin lowered nadir glucose values, while verapamil and liraglutide had no effect on hypoglycaemia. During the CGM periods, the treatments had no impact on hypoglycaemia, whereas acarbose and liraglutide reduced hyperglycaemia and glycaemic variability.

CONCLUSIONS

In an experimental setting, treatment with acarbose and pasireotide reduced PBH. Acarbose appears to have an overall glucose-stabilizing effect, whereas pasireotide leads to increased and sustained hyperglycaemia.

Efficacy and safety of lanreotide in postoperative dumping syndrome: A Phase II randomised and placebo-controlled study

Background

Data on the efficacy and safety of the long-acting somatostatin analogue lanreotide (LAN) for postoperative dumping syndrome are lacking.

Objective

We performed a double-blind, randomised and placebo-controlled crossover study of LAN Autogel® 90 mg in postoperative dumping.

Methods

Adults with a positive prolonged oral glucose tolerance test or spontaneous hypoglycaemia and total dumping score (DS) ≥ 10 despite dietary measures were treated with three monthly injections of LAN or placebo in a randomised crossover fashion with an eight-week wash-out period. Primary outcome was the effect of LAN on total DS versus placebo. Secondary outcomes were the effect on early and late DS, treatment assessment, quality of life and safety.

Results

Of 24 included patients (66.7% female; age 49.1 ± 2.1 years), 12 were randomised to LAN first. Pooled DS after three injections were lower compared to baseline after LAN (median=14 (interquartile range (IQR) 11.5-23) vs. median = 22 (IQR 16-27); p = 0.03) but not placebo (median = 20 (IQR 15-27) vs. median = 23 (IQR 13-29); p = 0.15). Improvement of early (median = 7.5 (IQR 4.5-13) vs. median = 12 (IQR 9-16); p = 0.03) but not late (median = 7 (IQR 6-10.3) vs. median = 9 (IQR 6-13); p = 0.26) DS was seen. Overall treatment assessment correlated with change in DS (r = -0.69, p = 0.004). Symptom improvement was not associated with changes in quality of life. Of the 81 reported adverse events, 44 occurred on LAN compared to 37 on placebo (p > 0.05), with seven serious adverse events on LAN.

Conclusions

LAN is effective for treating early postoperative dumping symptoms, although side effects are common and quality of life is not significantly affected.

Hypoglycemia After Gastric Bypass Successfully Treated With Calcium Channel Blockers: Two Case Reports

Postprandial hyperinsulinemic hypoglycemia is an uncommon yet well-established complication of Roux-en-Y gastric bypass (RYGB) that can result in serious morbidity and adversely affect quality of life. It is often unrecognized and may be difficult to diagnose. Management is challenging. As the number of bariatric procedures increases in parallel with the obesity epidemic, clinicians will be tasked to offer effective medical therapies for this complication. Two patients presented several years after RYGB with severe postprandial hypoglycemia. In one of the patients, we were able to document simultaneous postprandial hypoglycemia and hyperinsulinemia. Conventional treatment approaches, including medical nutrition therapy, acarbose, diazoxide, and octreotide, were either ineffective or limited by poor tolerance. Nifedipine and verapamil were used adjunctively with dietary modification, resulting in resolution of symptomatic hypoglycemic episodes. These agents are therapeutic options that can be used for some patients refractory to more traditional treatments. They should be tried before surgical procedures are considered for affected patients. These two cases demonstrate that calcium channel blockers may be efficacious and appropriate for select patients refractory to dietary interventions alone.

Possible relation between partial small bowel obstruction and severe postprandial reactive hypoglycemia after Roux-en-Y gastric bypass

BACKGROUND

Although dietary treatment ameliorates symptoms in most patients with postbariatric hypoglycemia (PBH), there is a subgroup with severe symptoms that do not respond sufficiently to either diet or drugs. A clinical observation showed that those patients additionally experienced postprandial abdominal discomfort or pain.

OBJECTIVES

This report describes patients with severe PBH following laparoscopic Roux-en Y gastric bypass undergoing corrective surgery to alleviate partial small bowel obstruction (kink, adhesions, dysfunctional anastomosis) and the subsequent outcome regarding symptoms of PBH.

SETTING

Sahlgrenska University Hospital, Sweden.

METHODS

Retrospective analysis regarding hypoglycemic symptoms from medical records and a complementary telephone interview.

RESULTS

Out of 80 patients treated for severe PBH at our tertiary academic surgical unit over the last 4 years, 38 underwent corrective surgery (adhesiolysis and/or a reconstructed jejuno-jejunostomy). Out of 21 patients using medications to control hypoglycemia before corrective surgery, 19 (90.5%) discontinued the medication, and 5 of 19 (26%) no longer needed to use a blood glucometer or a continuous glucose monitor. Although patients after surgical correction still could experience PBH, symptoms were less frequent and less severe. Postprandial abdominal symptoms decreased, and patients reported improved eating quality. Patient interviews revealed that 8% became entirely free of PBH symptoms after surgery and 71% experienced significant relief.

CONCLUSIONS

We propose a possible association between severe hypoglycemic symptoms after laparoscopic Roux-en Y gastric bypass and partial small bowel obstruction. Patients with PBH not responding adequately to diet and drug treatment may benefit from assessment and intervention for partial small bowel obstruction.

Postprandial hypoglycaemia after Roux-en-Y gastric bypass in individuals with type 2 diabetes

AIMS/HYPOTHESIS

Postprandial hypoglycaemia (PPHG) is a complication of Roux-en-Y gastric bypass (RYGB) surgery in normoglycaemic individuals. In type 2 diabetes, RYGB improves glucose metabolism, but whether this improvement is related to the later development of PPHG is not known. We investigated the presence and mechanisms of PPHG in individuals with type 2 diabetes undergoing RYGB.

METHODS

A total of 35 obese individuals with type 2 diabetes underwent an OGTT before and 24 months after surgery. PPHG was defined as a plasma glucose level of ≤3.3 mmol/l when not taking glucose-lowering agents. Insulin sensitivity was assessed by oral glucose insulin sensitivity index and beta-cell function by mathematical modelling of the plasma glucose, insulin and C-peptide concentrations.

RESULTS

After surgery, PPHG occurred in 11 of 35 individuals who underwent RYGB. Before surgery, BMI was lower, glycaemic control less good and time of glucose peak earlier in the PPHG vs No PPHG group, and the duration of diabetes was shorter with PPHG (all p ≤ 0.05). In addition, insulin sensitivity was greater in the PPHG than No PPHG group (p = 0.03). After surgery, BMI and fasting glucose and insulin levels decreased similarly in the two groups; insulin secretion during the first hour of the OGTT increased more in the PPHG than No PPHG group (p = 0.04). Beta-cell glucose sensitivity increased more in individuals with PPHG than those without (p = 0.002). Over the same time interval, the glucagon-like peptide 1 (GLP-1) response was lower in individuals with PPHG before surgery (p = 0.05), and increased more after surgery. At 2 h after glucose ingestion in the OGTT, postsurgery plasma glucagon level was significantly lower in the PPHG than No PPHG group.

CONCLUSIONS/INTERPRETATION

In morbidly obese individuals with type 2 diabetes, spontaneous PPHG may occur after bariatric surgery independently of a remission of diabetes. Before surgery, individuals had a shorter duration and were more insulin sensitive. Two years after surgery, these individuals developed greater beta-cell glucose sensitivity, and showed greater insulin and GLP-1 release early in the OGTT.

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.

Effectiveness of sitagliptin in a patient with late dumping syndrome after total gastrectomy

An 83-year-old man developed hypoglycemia after undergoing total gastrectomy for gastric cancer in 200X-4. The patient was admitted to our hospital in May 200X and placed on continuous glucose monitoring (CGM). Glycemic excursions were examined while on 3-meal/day (1700kcal) and 6-meal/day (1800kcal) diets. Oxyhyperglycemia followed about 2h later by a sudden drop in glucose levels was seen with both regimens. These findings were consistent with late dumping syndrome. CGM was continued, oral miglitol at 150mg/day or sitagliptin at 50mg/day was started, and glycemic excursions were compared. Results were similar for both drugs, with reductions in postprandial glucose elevations. Meal tolerance testing 3 months after oral sitagliptin, compared to before starting treatment, showed reductions in both early postprandial hyperglycemia and insulin hypersecretion. These findings suggest that DPP-4 inhibitors such as sitagliptin may be effective for treating post-gastrectomy late dumping syndrome.

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

OBJECTIVE

Postprandial hypoglycemia is an infrequent but disabling complication of Roux-en-Y gastric bypass (RYGB) surgery. Controversy still exists as to whether the postprandial hyperinsulinemia observed is due to inherent changes in pancreatic β-cell mass or function or to reversible alterations caused by RYGB anatomy. We aimed to determine if gastric feeding or reversal of RYGB would normalize postprandial glucose and hormone excursions in patients with symptomatic hypoglycemia.

METHODS

We completed a prospective study of six patients with severe symptomatic RYGB hypoglycemia who underwent RYGB reversal. An additional subject without hypoglycemia who underwent RYGB reversal was also studied prospectively. Mixed meal tolerance testing (MTT) was done orally (RYGB anatomy), via gastrostomy tube in the excluded stomach in the setting of RYGB, and several months after RYGB reversal.

RESULTS

All subjects reported symptomatic improvement of hypoglycemia after reversal of RYGB. Weight gain after reversal was moderate and variable. Postprandial glucose, insulin, and GLP-1 excursions were significantly diminished with gastric feeding and after reversal. Insulin secretion changed proportional to glucose levels and insulin clearance increased after reversal. Glucagon/insulin ratios were similar throughout study. We further compared the impact of modified sleeve gastrectomy reversal surgery to those with restoration of complete stomach and found no significant differences in weight regain or in postprandial glucose or hormone levels.

CONCLUSIONS

Reversal of RYGB is an effective treatment option for severe postprandial hypoglycemia. The pathophysiology of this disorder is primarily due to RYGB anatomy resulting in altered glucose, gut, and pancreatic hormone levels and decreased insulin clearance, rather than inherent β-cell hyperplasia or hyperfunction.

Roles of increased glycaemic variability, GLP-1 and glucagon in hypoglycaemia after Roux-en-Y gastric bypass

OBJECTIVE

Roux-en-Y gastric bypass (RYGB) surgery is currently the most effective treatment for diabetes and obesity. An increasingly recognized and highly disabling complication of RYGB is postprandial hypoglycaemia (PPH). The pathophysiology of PPH remains unclear with multiple mechanisms suggested including nesidioblastosis, altered insulin clearance and increased glucagon-like peptide-1 (GLP-1) secretion. Whilst many PPH patients respond to dietary modification, some have severely disabling symptoms. Multiple treatments are proposed, including dietary modification, GLP-1 antagonism, GLP-1 analogues and even surgical reversal, with none showing a more decided advantage over the others. A greater understanding of the pathophysiology of PPH could guide the development of new therapeutic strategies.

METHODS

We studied a cohort of PPH patients at the Imperial Weight Center. We performed continuous glucose monitoring to characterize their altered glycaemic variability. We also performed a mixed meal test (MMT) and measured gut hormone concentrations.

RESULTS

We found increased glycaemic variability in our cohort of PPH patients, specifically a higher mean amplitude glucose excursion (MAGE) score of 4.9. We observed significantly greater and earlier increases in insulin, GLP-1 and glucagon in patients who had hypoglycaemia in response to an MMT (MMT Hypo) relative to those that did not (MMT Non-Hypo). No significant differences in oxyntomodulin, GIP or peptide YY secretion were seen between these two groups.

CONCLUSION

An early peak in GLP-1 and glucagon may together trigger an exaggerated insulinotropic response to eating and consequent hypoglycaemia in patients with PPH.

Bariatric surgery - time to replace with GLP-1?

Obesity with a body mass index (BMI) over 30 kg/m² represents a significant risk for increased morbidity and mortality, with reduced life expectancy of about 10 years. Until now, surgical treatment has been the only effective longterm intervention. The currently standardized method of bariatric surgery, gastric bypass, means that many gastrointestinal peptide hormones are activated, yielding net reductions in appetite and food intake. Among the most important gut peptide hormones in this perspective is glucagon-like peptide-1 (GLP-1), which rises sharply after gastric bypass. Consistent with outcomes of this surgery, GLP-1 suppresses appetite and reduces food intake. This implies that GLP-1 has the potential to achieve a similar therapeutic outcome as gastric bypass. GLP-1 analogs, which are used for the treatment of type 2 diabetes mellitus, also lead to significant weight loss. Altered hormonal profiles after gastric bypass therefore indicate a logical connection between gut peptide hormone levels, weight loss and glucose homeostasis. Furthermore, combinations of GLP-1 with other gut hormones such as peptide YY (PYY) and cholecystokinin (CCK) may be able to reinforce GLP-1 driven reduction in appetite and food intake. Pharmacological intenvention in obesity by use of GLP-1 analogs (exenatide, liraglutide, albiglutide, dulaglutide, lixisenatide, taspoglutide) and inhibitors of dipeptidyl peptidase-IV (DPP-IV) degradation that inactivate GLP-1 (sitagliptin, vildagliptin), leading to reduced appetite and weight with positive effects on metabolic control, are realistically achievable. This may be regarded as a low-risk therapeutic alternative to surgery for reducing obesity-related risk factors in the obese with lower BMIs.

Postgastric bypass hypoglycaemia in a patient with end-stage renal disease: a diagnostic and management pitfall

Roux-en-Y gastric bypass (RYGB) surgery is currently one of the most popular procedures to aid weight loss. Hypoglycaemia associated with gastric bypass surgery is an underdiagnosed but life-threatening potential consequence of the surgical procedure. We present a case of a 44-year-old woman with end-stage renal disease presenting with refractory hypoglycaemia after 10 years of RYGB. Extensive history and work-up excluded medications, renal disease, insulinoma and dumping syndrome as the cause of hypoglycaemia. Dietary modifications or pharmacological trial of drugs did not ameliorate her symptoms with progressive worsening of hypoglycaemia leading to continuous dextrose infusion. Distal pancreatectomy was performed with subsequent resolution of hypoglycaemia. Surgical pathology results showed diffuse hyperplastic islet cells, confirming the diagnosis of postgastric bypass hypoglycaemia.

A case report: Liraglutide as a novel treatment option in late dumping syndrome

RATIONALE

Postprandial hyperinsulinemic hypoglycemia, known as late dumping syndrome, is a rare but often misdiagnosed complication after gastric surgery. The pathophysiological mechanisms are poorly understood and the treatment of this syndrome is challenging.

PATIENT CONCERNS

New-onset postsurgical late dumping syndrome after Toupet fundoplication.

DIAGNOSES

Sigstad Score, OGTT, CGM.

INTERVENTIONS

Daily subcutaneous injection of liraglutide (0.6 mg and 1.2 mg).

OUTCOMES

Reduction in fasting and postprandial peak insulin level with improvement in symptomatic hypoglycemic events.

LESSONS

Liraglutide may be a novel treatment option for postprandial hyperinsulinemic hypoglycemia after gastric surgery.

Dumping syndrome after esophageal, gastric or bariatric surgery: pathophysiology, diagnosis, and management

BACKGROUND

Dumping syndrome, a common complication of esophageal, gastric or bariatric surgery, includes early and late dumping symptoms. Early dumping occurs within 1 h after eating, when rapid emptying of food into the small intestine triggers rapid fluid shifts into the intestinal lumen and release of gastrointestinal hormones, resulting in gastrointestinal and vasomotor symptoms. Late dumping occurs 1-3 h after carbohydrate ingestion, caused by an incretin-driven hyperinsulinemic response resulting in hypoglycemia. Clinical recommendations are needed for the diagnosis and management of dumping syndrome.

METHODS

A systematic literature review was performed through February 2016. Evidence-based medicine was used to develop diagnostic and management strategies for dumping syndrome.

RESULTS

Dumping syndrome should be suspected based on concurrent presentation of multiple suggestive symptoms after upper abdominal surgery. Suspected dumping syndrome can be confirmed using symptom-based questionnaires, glycemia measurements and oral glucose tolerance tests. First-line management of dumping syndrome involves dietary modification, as well as acarbose treatment for persistent hypoglycemia. If these approaches are unsuccessful, somatostatin analogues should be considered in patients with dumping syndrome and impaired quality of life. Surgical re-intervention or continuous enteral feeding may be necessary for treatment-refractory dumping syndrome, but outcomes are variable.

CONCLUSIONS

Implementation of these diagnostic and treatment recommendations may improve dumping syndrome management.

Risk Factors for Spontaneously Self-Reported Postprandial Hypoglycemia After Bariatric Surgery

CONTEXT

Postprandial hypoglycemia (PPHG) is a recognized complication of Roux-en-Y gastric bypass (RYGB) surgery. Data on PPHG after laparoscopic sleeve gastrectomy (LSG) are scant.

OBJECTIVE

The objective of the study was to identify preoperative predictors of PPHG in subjects spontaneously self-reporting PPHG after RYGB or LSG. Patients, Setting, and Intervention: Nondiabetic patients spontaneously self-reporting symptoms/signs of PPHG (PPHG group, 21 RYGB and 11 LSG) were compared in a case-control design with subjects who never experienced spontaneous or oral glucose tolerance test (OGTT)-induced hypoglycemia over 24 months after surgery (No-PPHG group, 13 RYGB and 40 LSG). Paired pre- and postoperative 3-hour OGTTs were analyzed in all participants.

MAIN OUTCOME MEASURES

Insulin sensitivity was assessed by the oral glucose insulin sensitivity index and β-cell function by mathematical modeling of the C-peptide response to glucose.

RESULTS

Before surgery, the body mass index was lower in PPHG than No-PPHG patients in the RYGB (P = .002) and trended similarly in the LSG group (P = .08). Fasting glycemia and the glucose-OGTT nadir were lower in the PPHG than the No-PPHG subjects in both surgery groups. Before surgery, insulin sensitivity was higher in PPHG than No-PPHG in the RYGB (393 ± 55 vs 325 ± 44 mL/min^-1 · m^-2, P = .001) and LSG groups (380 ± 48 vs 339 ± 60 mL/min^-1 · m^-2, P = .05) and improved to a similar extent in all groups after surgery. Before surgery, β-cell glucose sensitivity was higher in PPHG than No-PPHG in both RYGB (118 ± 67 vs 65 ± 24 pmol/min^-1 · m² · mM^-1) and LSG patients (114 ± 32 vs 86 ± 33) (both P = .02) and improved in all subjects after surgery.

CONCLUSIONS

In subjects self-reporting PPHG after surgery, lower presurgery plasma glucose concentrations, higher insulin sensitivity, and better β-cell glucose sensitivity are significant predictors of PPHG after both RYGB and LSG.

Post-gastric bypass hypoglycaemia: a review

Bariatric surgery is a highly effective treatment for severe obesity, resulting in substantial weight loss and normalizing obesity-related comorbidities. However, long-term consequences can occur, such as postbariatric surgery hypoglycaemia. This is a challenging medical problem, and the number of patients presenting with it has been increasing. Roux-en-Y gastric bypass (RYGB) is the most popular bariatric procedure, and it is the surgery most commonly associated with the development of postbariatric surgery hypoglycaemia. To date, the pathogenesis of this condition has not been completely established. However, various factors - particularly increased postprandial glucagon-like peptide (GLP)-1 secretion - have been considered as crucial mediator. The mechanisms responsible for diabetic remission after bariatric surgery may be responsible for the development of hypoglycaemia, which typically occurs 1-3 h after a meal and is concurrent with inappropriate hyperinsulinaemia. Carbohydrate-rich foods usually provoke hypoglycaemic symptoms, which can typically be alleviated by strict dietary modifications, including carbohydrate restriction and avoidance of high glycaemic index foods and simple sugars. Few patients require further medical intervention, such as medications, but some patients have required a pancreatectomy. Because this option is not always successful, it is no longer routinely recommended. Clinical trials are needed to further determine the pathophysiology of this condition as well as the best diagnostic and treatment approaches for these patients.

Hypoglycaemia after gastric bypass: mechanisms and treatment

Hypoglycaemia after gastric bypass can be severe, but is uncommon, and is sometimes only revealed through monitoring glucose concentrations. The published literature is limited by the heterogeneity of the criteria used for diagnosis, arguing in favour of the Whipple triad with a glycaemia threshold of 55 mg/dl as the diagnostic reference. Women who lost most of their excess weight after gastric bypass, long after the surgery was performed, and who did not have diabetes before surgery are at the greatest risk. In this context, hypoglycaemia results from hyperinsulinism, which is either generated by pancreas anomalies (nesidioblastosis) and/or caused by an overstimulation of β cells by incretins, mainly glucagon-like peptide-1 (GLP-1). Glucose absorption is both accelerated and increased because of the direct communication between the gastric pouch and the jejunum. This is a post-surgical exaggeration of a natural adaptation that is seen in patients who have not undergone surgery in whom glucose is infused directly into the jejunum. There is not always a correspondence between symptoms and biological traits; however, hyperinsulinism is constant if hypoglycaemia is severe and there are neuroglucopenic symptoms. The treatment relies firstly on changes in eating habits, splitting food intake into five to six daily meals, slowing gastric emptying, reducing the glycaemic load and glycaemic index of foods, using fructose and avoiding stress at meals. Pharmacological treatment with acarbose is efficient, but other drugs still need to be validated in a greater number of subjects (insulin, glucagon, calcium channel blockers, somatostatin analogues and GLP-1 analogues). Lastly, if the surgical option has to be used, the benefits (efficient symptom relief) and the risks (weight regain, diabetes) should be weighed carefully.