Usefulness of acarbose and dietary modifications to limit glycemic variability following Roux-en-Y gastric bypass as assessed by continuous glucose monitoring

Canagliflozin or acarbose versus placebo to ameliorate post-bariatric hypoglycaemia - The HypoBar I randomized clinical trial protocol

INTRODUCTION

Post-bariatric hypoglycaemia (PBH) is a rare yet disabling clinical condition, mostly reported after Roux-en-Y gastric bypass (RYGB) surgery. RYGB is one of the most widely used and effective bariatric procedures. The pathophysiology of PBH remains unclear, and treatment options are limited in effectiveness and/or carry significant side effects. Acarbose slows carbohydrates digestion and absorption and is generally considered first-line pharmacological treatment for PBH but its gastrointestinal side effects limit patient compliance. Canagliflozin inhibits intestinal and renal sodium-dependent glucose absorption and reduces postprandial excursions of glucose, insulin and incretins after RYGB - effects that could be beneficial in ameliorating PBH.

AIMS

The trial aims to investigate how blood glucose levels are affected during daily living in subjects with PBH during treatment with canagliflozin or acarbose compared with placebo, and to study the meal-induced entero-endocrine mechanisms implied in the treatment responses.

METHODS

In a double-blinded, randomized, crossover clinical trial, HypoBar I will investigate the effectiveness in reducing the risk of PBH, safety, ambulatory glucose profile and entero-endocrine responses when PBH is treated with canagliflozin 300 mg twice daily during a 4-week intervention period, compared with acarbose 50 mg thrice daily or placebo.

ETHICS AND DISSEMINATION

HypoBar I is approved by the Local regulatory entities. Results will be published in peer-reviewed journals.

CONCLUSION

If effective, well-tolerated and safe, canagliflozin could be a novel treatment for people with PBH. HypoBar I might also unravel new mechanisms underlying PBH, potentially identifying new treatment targets.

TRIAL REGISTRATION

EudraCT number 2022-000157-87.

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.

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.

Use of Continuous Glucose Monitoring in Patients Following Bariatric Surgery: A Scoping Review

The objective of this scoping review was to summarize the emerging literature on the use of continuous glucose monitoring (CGM) in post-bariatric surgery patients, with a focus on its features (e.g., device, mode, and accuracy), as well as purposes and outcomes of utilization. Three databases (PubMed, EMBASE, and Web of Science) were searched to obtain relevant studies. Results suggested that most studies used CGM for 3-7 days under blinded mode. Accuracy data were available in only one study, which reported a mean absolute relative difference of 21.7% for Freestyle Libre. The primary applications of CGM were for elucidating glucose patterns and assessing glycemic treatment outcomes. No study has tested the effect of CGM as an intervention strategy to enhance glucose control.

Clinical Presentation and Diagnostic Approach to Hypoglycemia in Adults Without Diabetes Mellitus

OBJECTIVE

To review the clinical presentation, causes, and diagnostic approach to spontaneous hypoglycemia in adults without diabetes mellitus.

METHODS

A literature review was performed using the PubMed and Google Scholar databases.

RESULTS

Hypoglycemia is uncommon in people who are not on glucose-lowering medications. Under normal physiologic conditions, multiple neural and hormonal counterregulatory mechanisms prevent the development of abnormally low levels of plasma glucose. If spontaneous hypoglycemia is suspected, the Whipple triad should be used to confirm hypoglycemia before pursuing further diagnostic workup. The Whipple criteria include the following: (1) low levels of plasma glucose, (2) signs or symptoms that would be expected with low levels of plasma glucose, and (3) improvement in those signs or symptoms when the level of plasma glucose increases. Spontaneous hypoglycemia can be caused by conditions that cause endogenous hyperinsulinism, including insulinoma, postbariatric hypoglycemia, and noninsulinoma pancreatogenous hypoglycemia. Spontaneous hypoglycemia can also be seen with critical illness, hepatic or renal dysfunction, hormonal deficiency, non-diabetes-related medications, and non-islet cell tumors. The initial diagnostic approach should begin by obtaining a detailed history of the nature and timing of the patient's symptoms, medications, underlying comorbid conditions, and any acute illness. A laboratory evaluation should be conducted at the time of the spontaneous symptomatic episode. Supervised tests such as a 72-hour fast or mixed-meal test may be needed to recreate the situation under which the patient is likely to experience symptoms.

CONCLUSION

We provide an overview of the physiology of counterregulatory response to hypoglycemia, its causes, and diagnostic approaches to spontaneous hypoglycemia in adults.

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.

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.

Use of continuous glucose monitoring in obesity research: A scoping review

BACKGROUND

This scoping review provides a timely synthesis of the use of continuous glucose monitoring in obesity research with considerations to adherence to continuous glucose monitor devices and metrics most frequently reported.

METHODS

This scoping review was conducted adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist. Eligible studies (n = 31) evaluated continuous glucose monitor use in research on participants, of all ages, with overweight or obesity.

RESULTS

Reviewed studies varied in duration from one to 84 days (mean: 8.74 d, SD 15.2, range 1-84 d) with 889 participants total (range: 11-118 participants). Across all studies, the mean percent continuous glucose monitor wear time (actual/intended wear time in days) was 92% (numerator - mean: 266.1 d, SD: 452, range: 9-1596 d/denominator - mean: 271.6 d, SD: 451.5, range: 9-1596 d). Continuous glucose monitoring was utilized to provide biofeedback (n = 2, 6%), monitor dietary adherence (n = 2, 6%), and assess glycemic variability (n = 29, 93%). The most common variability metrics reported were standard deviation (n = 19, 62%), area under the curve (n = 12, 39%), and glycemic range (n = 12, 39%).

CONCLUSIONS

Available evidence suggests that continuous glucose monitoring is a well-tolerated and versatile tool for obesity research in pediatric and adult patients. Future investigation is needed to substantiate the feasibility and utility of continuous glucose monitors in obesity research and maximize comparability across studies.

International consensus on the diagnosis and management of dumping syndrome

Dumping syndrome is a common but underdiagnosed complication of gastric and oesophageal surgery. We initiated a Delphi consensus process with international multidisciplinary experts. We defined the scope, proposed statements and searched electronic databases to survey the literature. Eighteen experts participated in the literature summary and voting process evaluating 62 statements. We evaluated the quality of evidence using grading of recommendations assessment, development and evaluation (GRADE) criteria. Consensus (defined as >80% agreement) was reached for 33 of 62 statements, including the definition and symptom profile of dumping syndrome and its effect on quality of life. The panel agreed on the pathophysiological relevance of rapid passage of nutrients to the small bowel, on the role of decreased gastric volume capacity and release of glucagon-like peptide 1. Symptom recognition is crucial, and the modified oral glucose tolerance test, but not gastric emptying testing, is useful for diagnosis. An increase in haematocrit >3% or in pulse rate >10 bpm 30 min after the start of the glucose intake are diagnostic of early dumping syndrome, and a nadir hypoglycaemia level <50 mg/dl is diagnostic of late dumping syndrome. Dietary adjustment is the agreed first treatment step; acarbose is effective for late dumping syndrome symptoms and somatostatin analogues are preferred for patients who do not respond to diet adjustments and acarbose.

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.

Gastroparesis and Dumping Syndrome: Current Concepts and Management

Gastroparesis and dumping syndrome both evolve from a disturbed gastric emptying mechanism. Although gastroparesis results from delayed gastric emptying and dumping syndrome from accelerated emptying of the stomach, the two entities share several similarities among which are an underestimated prevalence, considerable impairment of quality of life, the need for a multidisciplinary team setting, and a step-up treatment approach. In the following review, we will present an overview of the most important clinical aspects of gastroparesis and dumping syndrome including epidemiology, pathophysiology, presentation, and diagnostics. Finally, we highlight promising therapeutic options that might be available in the future.

Endoscopic Gastrojejunal Revision (Transoral Outlet Reduction) for Persistent Hypoglycemia After Gastric Bypass

BACKGROUND

The patient presented with symptomatic postprandial biweekly hypoglycemic seizures. Her hypoglycemic episodes were aggravated by stress and also occurred during sleep. She managed these hypoglycemic episodes with an endocrinologist, trying both nutritional and medical management without successful control of her symptoms. An endoscopic gastrojejunal revision (EGJR) was recommended to provide more restriction and prolong transit time into the Roux limb to decrease the chance of postoperative dumping syndrome and subsequent hypoglycemia.

METHODS

This video is a case study of an EGJR done for persistent postoperative hypoglycemia. The gastroscope was introduced and using Argon Plasma Coagulation at a flow of 8 liters/min and 30 watts; the mucosa around the gastrojejunal stoma was ablated circumferentially. This was done to decrease bleeding from needle placement and to promote adherence of the mucosa after the sutures were placed. The purse-string technique was favored for this procedure due to an inherent reduction in suture tension. Several full-thickness bites were taken to narrow the stoma from 20 to 4 mm in diameter.

RESULTS

The patient was discharged home the same day following the procedure. She was placed on a two week liquid bariatric postoperative diet. At two week follow-up, the patient reported normal  blood sugars and no hypoglycemic episodes since surgery. At six month follow-up, the patient reported significant improvement in her hypoglycemia symptoms, and no further syncopal episodes or seizures.

CONCLUSION

We believe this case demonstrates that endoscopic gastrojejunal revision (or EGJR) is an effective treatment option for postprandial hypoglycemia following Roux-en-Y gastric bypass.

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.

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.

Long-term pharmacotherapy considerations in the bariatric surgery patient

PURPOSE

Pharmacists' role in optimizing long-term pharmacotherapy for bariatric surgery patients is detailed.

SUMMARY

Bariatric surgery patients provide a difficult challenge in terms of many pharmacotherapy issues, especially in the chronic care setting, where data on long-term effects of bariatric surgery are limited. The most common procedures are Roux-en-Y gastric bypass (RYGB), adjustable gastric banding, and sleeve gastrectomy. Sleeve gastrectomy has become the most common procedure in the United States, primarily because it has less overall chronic malabsorption effects than RYGB. Pharmacotherapy management is complicated by rapid weight loss combined with a number of pharmacokinetic changes, such as decreased absorption of some medications due to altered gastrointestinal tract anatomy and potentially increased concentrations of some medications due to a decreased volume of distribution resulting from weight loss. Nutritional and metabolic supplementation are of the utmost importance in order to limit deficiencies that can lead to a number of conditions. Many chronic diseases, including hypertension, diabetes, gastroesophageal reflux disease, and urinary incontinence, are improved by bariatric surgery but require close monitoring to ensure the effectiveness of maintenance pharmacotherapy and avoidance of adverse effects. Psychotropic medication management is also an important pharmacotherapy concern, as evidenced by antidepressants being the most commonly used medication class among preoperative bariatric surgery patients.

CONCLUSION

Pharmacists have an increasing role in the chronic management of the bariatric surgery patient due to their knowledge of medication dosage forms and expertise in disease states affected by bariatric surgery.

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.

Postprandial Hypoglycemia in Children after Gastric Surgery: Clinical Characterization and Pathophysiology

BACKGROUND/AIMS

Dumping syndrome is a common complication in children after fundoplication and other gastric surgeries and is characterized by postprandial hypoglycemia (PPH). Children with PPH have an exaggerated GLP-1 response to a meal with an exaggerated insulin surge and subsequent hypoglycemia. We evaluated the role of GLP-1 in the pathogenesis of PPH by examining the effects of GLP-1 receptor blockade on glucose and insulin response to a meal.

METHODS

Six children with known PPH after surgery underwent a mixed meal tolerance test with/without the GLP-1 receptor antagonist exendin-(9-39) using an open-label crossover design.

RESULTS

Average nadir plasma glucose concentration was ≥65 mg/dl in all treatment conditions; however, 3 out of the 6 subjects had a nadir plasma glucose <65 mg/dl during vehicle infusion, while only 1 out of the 6 had a nadir plasma glucose <65 mg/dl during infusion of exendin-(9-39). Exendin-(9-39) suppressed postmeal insulin concentrations when compared to vehicle, with a lower peak insulin concentration observed in the children who received 500 pmol/kg/min of exendin-(9-39) (131.3 ± 125.1 pmol/l) compared to children who received 300 pmol/kg/min (231.1 ± 153.4 pmol/l) or vehicle (259.7 ± 120.2 pmol/l). Gastric emptying was not different between groups.

CONCLUSION

Our results suggest that the exaggerated insulin response to a meal is at least in part due to the effects of GLP-1 on the pancreatic β-cell and suggest that GLP-1 receptor antagonists may represent a potential avenue of treatment for children with PPH.

Concurrent Therapy with a Low-carbohydrate Diet and Miglitol Remarkably Improved the Postprandial Blood Glucose and Insulin Levels in a Patient with Reactive Hypoglycemia due to Late Dumping Syndrome

Reactive hypoglycemia induced by late dumping syndrome is often observed after gastrectomy. However, no effective therapy has yet been fully established. We herein describe a case in which concurrent therapy with a low-carbohydrate diet using low-glycemic-index food and an alpha-glucosidase inhibitor, miglitol, very effectively ameliorated the postprandial fluctuations in the blood glucose and plasma insulin levels in a patient with reactive hypoglycemia due to late dumping syndrome following total gastrectomy. The administration of miglitol under a low-carbohydrate diet using low-glycemic-index food may therefore be an ideal treatment for reactive hypoglycemia due to late dumping syndrome.

ß-cell pancreatic dysfunction plays a role in hyperglycemic peaks observed after gastric bypass surgery of obese patients

BACKGROUND

Early and intense hyperglycemic peaks are observed after Roux-en-Y gastric bypass (RYGB).

OBJECTIVES

The aim of this observational study was to compare the ß-cell pancreatic function of patients with (PEAK) and without hyperglycemic peaks (NOPEAK).

SETTING

Referral bariatric surgery center.

METHODS

Insulin secretion rate, clearance, and sensitivity and ß-cell and rate sensitivities were computed after a 75-g oral glucose tolerance test in 42 patients who underwent RYGB.

RESULTS

PEAK patients (n = 18; 30-min glycemia>10.4 mmol/L) did not differ from NOPEAK patients (n = 24) in their presurgery or weight loss characteristics. PEAK patients had significantly higher plasma concentrations of glucose and C-peptide than did NOPEAK patients, whereas insulin and glucagon-like peptide-1 concentrations did not differ. The insulin secretion rate and whole-body insulin clearance (208%) were significantly greater, but insulin sensitivity was significantly less (48%) in PEAK patients. Insulin secretion normalized to plasma glucose was significantly lower in PEAK patients, and the disposition index was reduced (35% to 41% of the values in NOPEAK patients).

CONCLUSION

We conclude that RYGB reveals a series of dysfunctions leading to hyperglycemia in a subset of patients. In PEAK patients, an insufficient adaptation of ß-cell function to glycemia, an increased insulin clearance, and a decreased insulin sensitivity cumulated to contribute to hyperglycemic peaks.

Acarbose: safe and effective for lowering postprandial hyperglycaemia and improving cardiovascular outcomes

α-Glucosidase inhibitors (AGIs) are a class of oral glucose-lowering drugs used exclusively for treatment or prevention of type 2 diabetes mellitus. AGIs act by altering the intestinal absorption of carbohydrates through inhibition of their conversion into simple sugars (monosaccharides) and thus decrease the bioavailability of carbohydrates in the body, significantly lowering blood glucose levels. The three AGIs used in clinical practice are acarbose, voglibose and miglitol. This review will focus on the cardiovascular properties of acarbose. The current available data suggest that AGIs (particularly acarbose) may be safe and effective for the treatment of prediabetes and diabetes.

Impact of Carbohydrate Content and Glycemic Load on Postprandial Glucose After Roux-en-Y Gastric Bypass

BACKGROUND

Abnormal glucose profiles have been described after Roux-en-Y gastric bypass (RYGB) with intense postprandial hyperglycemic peaks in some but not all the patients. The underlying mechanisms of these anomalies are not totally understood.

OBJECTIVE

The aim of this study is to determine whether or not the composition of the meal impacts the existence and maximum interstitial glucose (IG) concentration, measured under real-life conditions.

DESIGN

Retrospective cohort.

SETTING

Referral bariatric surgery left.

METHODS

Continuous glucose monitoring (CGM) and meal composition were recorded for at least 3 days on an outpatient basis in 56 patients after RYGB. The presence of postprandial peaks defined by IG above 140 mg/dl, the maximum postprandial IG, the carbohydrate content, and the glycemic load of the meals were analyzed.

RESULTS

Thirty-two patients had a hyperglycemic peak (PEAK), and 24 did not (NO PEAK). The average max IG was 159.6 ± 33.0 mg/dl in PEAK individuals and 111.8 ± 13.0 mg/dl in NO PEAK. Age was significantly higher in PEAK, but no other parameter was different between the two groups, including meal composition. In the PEAK patients, in multivariate analyses, carbohydrate content in model one and glucose load in model two explained respectively 50 and 26 % of maximum IG variance. For each gram of ingested carbohydrates, interstitial glucose increased by 1.68 mg/dl.

CONCLUSIONS

Following a gastric bypass, under real-life conditions, irrespective of the carbohydrate content of the meal, some patients develop postprandial hyperglycemic peaks, whereas others do not. In patients with postprandial hyperglycemic peaks, the maximum IG depends on the carbohydrate content of the meal.

Diagnostic tools for post-gastric bypass hypoglycaemia

In spite of its evident success, several late complications can occur after gastric bypass surgery. One of these is post-gastric bypass hypoglycaemia. No evidence-based guidelines exist in the literature on how to confirm the presence of this syndrome. This study aims to describe and compare the tests aimed at making a diagnosis of post-gastric bypass hypoglycaemia and to provide a diagnostic approach based upon the available evidence. A search was conducted in PubMed, Cochrane and Embase. A few questionnaires have been developed to measure the severity of symptoms in post-gastric bypass hypoglycaemia but none has been validated. The gold standard for provocation of a hypoglycaemic event is the oral glucose tolerance test or the liquid mixed meal tolerance test. Both show a high prevalence of hypoglycaemia in post-gastric bypass patients with and without hypoglycaemic complaints as well as in healthy volunteers. No uniformly established cut-off values for glucose concentrations are defined in the literature for the diagnosis of post-gastric bypass hypoglycaemia. For establishing an accurate diagnosis of post-gastric bypass hypoglycaemia, a validated questionnaire, in connection with the diagnostic performance of provocation tests, is the most important thing missing. Given these shortcomings, we provide recommendations based upon the current literature.

[Dumping syndrome: Diagnostics and therapeutic options]

BACKGROUND

Dumping syndrome is a common complication after surgery of the upper gastrointestinal tract with symptoms ranging from mild gastrointestinal discomfort and moderate vasomotor disturbances, to severe hyperinsulinemic hypoglycemia. Due to the increasing number of bariatric procedures being performed worldwide, bariatric surgery has become the most common cause for this disease entity.

OBJECTIVE

The aim of this review is to highlight the evidence for the physiological mechanisms contributing to dumping syndrome after the two most common bariatric surgery procedures, Roux-en-Y gastric bypass and sleeve gastrectomy, to discuss technical aspects of the procedures underlying the development of the syndrome, patient-related predictive factors and other differential diagnoses, together with diagnostic and therapeutic algorithms.

Hypoglycemia in everyday life after gastric bypass and duodenal switch

DESIGN

Gastric bypass (GBP) and duodenal switch (DS) in morbid obesity are accompanied by marked metabolic improvements, particularly in glucose control. In recent years, episodes of severe late postprandial hypoglycemia have been increasingly described in GBP patients; data in DS patients are scarce. We recruited three groups of subjects; 15 GBP, 15 DS, and 15 non-operated overweight controls to examine to what extent hypoglycemia occurs in daily life.

METHODS

Continuous glucose monitoring (CGM) was used during 3 days of normal activity. The glycemic variability was measured by mean amplitude of glycemic excursion and continuous overall net glycemic action. Fasting blood samples were drawn, and the patients kept a food and symptom log throughout the study.

RESULTS

The GBP group displayed highly variable CGM curves, and 2.9% of their time was spent in hypoglycemia (<3.3  mmol/l, or 60  mg/dl). The DS group had twice as much time in hypoglycemia (5.9%) and displayed CGM curves with little variation as well as lower HbA1c levels (29.3 vs 35.9 mmol/mol, P<0.05). Out of a total of 72 hypoglycemic episodes registered over the 3-day period, 70 (97%) occurred in the postprandial state and only about one-fifth of the hypoglycemic episodes in the GBP and DS groups were accompanied by symptoms. No hypoglycemias were seen in controls during the 3-day period.

CONCLUSION

Both types of bariatric surgery induce marked, but different, changes in glucose balance accompanied by frequent, but mainly unnoticed, hypoglycemic episodes. The impact and mechanism of hypoglycemic unawareness after weight-reduction surgery deserves to be clarified.

Is type 2 diabetes really resolved after laparoscopic sleeve gastrectomy? Glucose variability studied by continuous glucose monitoring

The study was carried out on type 2 diabetic obese patients who underwent laparoscopic sleeve gastrectomy (LSG). Patients underwent regular glycemic controls throughout 3 years and all patients were defined cured from diabetes according to conventional criteria defined as normalization of fasting glucose levels and glycated hemoglobin in absence of antidiabetic therapy. After 3 years of follow-up, Continuous Glucose Monitoring (CGM) was performed in each patient to better clarify the remission of diabetes. In this study, we found that the diabetes resolution after LSG occurred in 40% of patients; in the other 60%, even if they showed a normal fasting glycemia and A1c, patients spent a lot of time in hyperglycemia. During the oral glucose tolerance test (OGTT), we found that 2 h postload glucose determinations revealed overt diabetes only in a small group of patients and might be insufficient to exclude the diagnosis of diabetes in the other patients who spent a lot of time in hyperglycemia, even if they showed a normal glycemia (<140 mg/dL) at 120 minutes OGTT. These interesting data could help clinicians to better individualize patients in which diabetes is not resolved and who could need more attention in order to prevent chronic complications of diabetes.

Remission of type 2 diabetes after Roux-en-Y gastric bypass or sleeve gastrectomy is associated with a distinct glycemic profile

BACKGROUND

Roux-en-Y gastric bypass (RYGBP) and sleeve gastrectomy (SG) have been associated with a high remission rate of type 2 diabetes mellitus (T2DM). However, whether such remission is associated with full restoration of postprandial glucose profile and/or the potentially nonrestored glycemic profile is associated with altered beta cell function, and relapse of T2DM over time is unknown.

METHODS

Cross-sectional studies comparing (1) glucose and proinsulin/insulin response to a standardized liquid mixed meal (SLMM) challenge (n = 31), (2) glucose response in normal living conditions assessed using continuous glucose monitoring (CGM) (n = 16), and prospective observational study comparing (3) rates of relapse of T2DM after surgery (n = 232) in subjects with remission of T2DM ensuing RYGBP or SG.

RESULTS

In RYGB individuals, SLMM elicited faster and sharper rise in plasma glucose compared with SG, with 88.2% and 42.9% of the study subjects presenting respectively a peak glucose more than 180 mg/dL (all, P < 0.05). During CGM, average percent time in hyperglycemic and hypoglycemic range was larger in RYGBP (respectively, 4.6% and 12.7%) compared with SG subjects (respectively, 0.4% and 3.2%; both P < 0.05). However, (1) no differences were found in fasting or stimulated proinsulin/insulin ratio, and (2) higher rates of T2DM relapse were observed after SG (hazard ratio: 2.339; P = 0.034).

CONCLUSIONS

Remission of T2DM after RYGBP and SG is associated with distinct glycemic profiles. However, longer time spent in hyperglycemia and in hypoglycemia after RYGBP compared with SG is not associated with persistence of altered beta cell function or higher rates of relapse of T2DM over time.

Increased risk of OGTT-induced hypoglycemia after gastric bypass in severely obese patients with normal glucose tolerance

BACKGROUND

Hypoglycemic episodes are described after bariatric surgery.

OBJECTIVE

To report the prevalence of hypoglycemia after a 75 g oral glucose load (OGTT) after Roux-en-Y gastric bypass (RYGB) and adjustable gastric banding (LAGB), and to identify predicting factors.

SETTING

Bariatric surgery referral center.

METHODS

Prospective cohort of 351 consecutive patients before and 12 months after bariatric surgery, on whom an OGTT was performed. The main outcome measure was postchallenge hypoglycemia (PCHy), defined as a 120 minute plasma glucose value<2.8 mmol/L (50.4 mg/dL).

RESULTS

Only patients with an RYGB presented with PCHy. It occurred in 23 patients or a prevalence of 10.4% after an RYGB. The OR was 25.5 (95% CI 3.4-191; P<.001) compared with before surgery. Patients with PCHy after surgery had a lower glycated hemoglobin (HbA1c), and a lower 2-hour postchallenge value before surgery. Before surgery, patients with normal glucose tolerance had an increased risk of PCHy after surgery (OR 8.6, 95% CI 2.0-37.6; P< .001).

CONCLUSIONS

The prevalence of OGTT-induced hypoglycemia is increased 25.5 times, 12 months after an RYGB. This is not observed after a gastric banding.

Hypoglycemia after Roux-En-Y gastric bypass: detection rates of continuous glucose monitoring (CGM) versus mixed meal test

BACKGROUND

Neuroglucopenic hypoglycemia might be an underestimated threat for roux-en-Y gastric bypass (RYGB) patients leading to fatigue, syncope, seizures or even accidental deaths. Different measurements can assess hypoglycemia such as a finger-stick glucometer, an Oral Glucose Tolerance Test, a Mixed Meal-Test (MMT) or, as introduced recently, continuous glucose monitoring (CGM).

SETTING

University Hospital, Austria.

METHODS

To assess the incidence of hypoglycemic episodes under real life conditions, 5-day CGM was performed in a series of 40 patients at a mean of 86 months after RYGB. The detection rates were compared to a mixed meal-test.

RESULTS

CGM detected hypoglycemic episodes of <55 mg/dL or <3.05 mmol/L in 75% of the patients, while MMT indicated hypoglycemia in 29% of the patients. CGM also detected nocturnal hypoglycemic episodes in 15 (38%) of the patients. A mean of 3±1 hypoglycemic episodes per patient with a mean duration of 71±25 minutes were observed by CGM.

CONCLUSIONS

Assessed under real life conditions by CGM, post-RYGB hypoglycemia was found more frequently than expected. CGM revealed hypoglycemic episodes in 75% of the patients while MMT had a lower detection rate. Thus, CGM may have a role for screening but also for the evaluation of dietary modifications, drug therapy or surgical intervention for hypoglycemia after RYGB.

More symptoms but similar blood glucose curve after oral carbohydrate provocation in patients with a history of hypoglycemia-like symptoms compared to asymptomatic patients after Roux-en-Y gastric bypass

BACKGROUND

Laparoscopic Roux-en-Y gastric bypass (LRYGB) is an effective treatment for obesity through altering several physiologic mechanisms. Some patients experience symptoms suggestive of hypglycemia after LRYGB, but whether these symptoms always are associated with low blood glucose are unclear. The objective of this study was to investigate the correlation between symptoms suggestive of hypglycemia, plasma glucose levels and gut hormones involved in glycemic control.

METHODS

Eight LRYGB patients with hypglycemia-like symptoms (SY) and 8 patients with no hypglycemia-like symptoms (ASY) ingested a liquid carbohydrate meal. Insulin, plasma-glucose, glucagon-like peptide 1 (GLP-1) and glucagon were measured intermittently 180 minutes postprandially. In addition, pulse rate, blood pressure and symptoms were assessed.

RESULTS

Plasma glucose at 120 min was lower in the ASY mean (95% CI) 2.4 (1.6,3.3) mmol/L (43.2 mg/dL) compared to the SY group 3.0 (3.1,4.6) mmol/L (54.6 mg/dL), (P = .050). The ASY group had larger reduction in plasma glucose than the SY group from pre- to 120 min postmeal -2.2 (-2.8,-1.7) mmol/L (-39.6 mg/dL) versus -1.1 (-1.7,-0.4) mmol/L (-19.8 mg/dL), (P = .011). The concentrations of insulin, GLP-1 and glucagon did not differ significantly between groups. Blood pressure was similar between groups, but the AUC for pulse rate was higher in the SY than ASY group 13009 (11148,14870) versus 11569 (10837,12300) beats/180 minutes, (P = .038). The SY group reported more symptoms than the ASY group, AUC for Sigstad scale 60 to 180 minutes was 970 (-274,1667) for SY versus 170 for ASY (-39,379), (P = .028).

CONCLUSION

Patients with a history of symptoms suggestive of hypglycemia after LRYGB neither demonstrated lower plasma glucose nor greater insulin response compared to asymptomatic patients in response to a liquid carbohydrate meal, but perceived more symptoms.

On the potential of acarbose to reduce cardiovascular disease

In the emerging landscape of cardiovascular (CV) outcome trials evaluating the effects of blood glucose lowering drugs in individuals with type 2 diabetes, it is becoming increasingly apparent that since the promising signals coming from the United Kingdom Prospective Diabetes Study (UKPDS) no unequivocal benefits have been established for any single therapy thus far. There is an unmet need for introducing an effective pharmacological agent which could target both correlates of glycaemic regulation and CV risk factors, to ameliorate the enormous burden of fatal and non-fatal CV events in diabetic patients. Acarbose, like other alpha-glucosidase inhibitors (AGIs), has been proven to be an effective antidiabetic treatment for decades, but the overall significant impact of this class of drugs on modulating CV risk has only recently been appreciated. Accumulating evidence has shown that apart from its multiple effects on primarily postprandial glucose dysmetabolism, a key component of mechanisms linked to increased incidence of CV events, acarbose therapy also associates with a favorable impact on an array of surrogate markers of CV disease. Data stemming from in vitro testing of human cell lines as well as from preliminary trials in diabetic populations, like the Study to Prevent Non-Insulin-Dependent Diabetes Mellitus (STOP-NIDDM) trial, have highlighted – though not undisputed – the potential beneficial effects of the drug on CV morbidity. Large scale trials, like the ongoing Acarbose Cardiovascular Evaluation (ACE) trial, aim at conclusively establishing such a positive effect in patients with coronary heart disease and impaired glucose tolerance. In view of its usually acceptable level of side effects that are, if they occur, mostly limited to transient gastrointestinal symptoms, acarbose could well be a strong future player in CV disease secondary prevention. Current discouraging results from many trials of antidiabetic medications to significantly lower CV event rates in diabetic patients, should only draw further attention on alternative glucose lowering agents, among which acarbose is indeed promising.

Bariatric emergencies: current evidence and strategies of management

BACKGROUND

The demand for bariatric surgery is increasing and the postoperative complications are seen more frequently. The aim of this paper is to review the current outcomes of bariatric surgery emergencies and to formulate a pathway of safe management.

METHODS

The PubMed and Google search for English literatures relevant to emergencies of bariatric surgery was made, 6358 articles were found and 90 papers were selected based on relevance, power of the study, recent papers and laparoscopic workload. The pooled data was collected from these articles that were addressing the complications and emergency treatment of bariatric patients. 830,998 patients were included in this review.

RESULTS

Bariatric emergencies were increasingly seen in the Accident and Emergency departments, the serious outcomes were reported following complex operations like gastric bypass but also after gastric band and the causes were technical errors, suboptimal evaluation, failure of effective communication with bariatric teams who performed the initial operation, patients factors, and delay in the presentation. The mortality ranged from 0.14%-2.2% and increased for revisional surgery to 6.5% (p = 0.002). Inspite of this, mortality following bariatric surgery is still less than that of control group of obese patients (p = value 0.01).

CONCLUSIONS

Most mortality and catastrophic outcomes following bariatric surgery are preventable. The awareness of bariatric emergencies and its effective management are the gold standards for best outcomes. An algorithm is suggested and needs further evaluation.