Post-bypass hypoglycaemia: A review of current findings

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.

Dumping Syndrome in Children: A Narrative Review

Dumping syndrome (DS) is a typical side effect of stomach surgery, which includes cancer, non-cancer esophageal and gastric surgery, and bariatric surgery. It is marked by the fast evacuation of undigested food from the stomach into the small intestine, which causes a variety of symptoms. Early dumping symptoms include gastrointestinal symptoms such as stomach discomfort, diarrhea, and nausea, as well as vasomotor symptoms such as drowsiness and face flushing, and occur within the first hour following a meal. Late dumping symptoms appear one to three hours after a meal and are related to reactive hypoglycemia, resulting in hypoglycemia, sweating, palpitations, and confusion. Early dumping pathophysiology involves abnormalities in stomach structure and function, which result in rapid transit of stomach contents to the duodenum, insufficient digestion, and fluid transfers from the vascular compartment to the intestine. Late dumping occurs as a result of hyperinsulinemia caused by the fast passage of undigested foods to the gut. Symptom-based questionnaires and diagnostic testing such as plasma glucose measurement and stomach emptying studies can be used to confirm a diagnosis of DS. The primary approach to managing DS is dietary modifications, including eating smaller, more frequent meals and avoiding high glycemic index carbohydrates. Dietary supplements and medications may be used to slow down gastric emptying or control blood glucose levels. Pharmacological options include alpha-glycosidase inhibitors, somatostatin analogs, glucagon-like peptide-1 analogs, and sodium-glucose cotransporter inhibitors. In severe cases, refractory to conservative measures, surgical interventions may be considered. DS can arise in children following gastric surgery for obesity or corrective surgery for congenital abnormalities. It is frequently misdiagnosed and can have serious implications, such as hypoglycemia-related cognition deficits. Screening and early identification using glucose tolerance testing and continuous glucose monitoring (CGM) are critical in at-risk youngsters. Children's treatment techniques are similar to those used in adults, with dietary changes and medication therapies serving as the cornerstone of care. Overall, DS is a complex condition that requires a multidisciplinary approach to diagnosis and management. Further research is needed to improve understanding of its pathophysiology and optimize treatment strategies, particularly in children. This review aims to provide a well-rounded informative summary of the most recent literature on the under-recognized clinical and scientific aspects of DS among the children age group. It incorporates the quality of life, pathophysiology, diagnosis, prevalence, and treatment.

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.

Bariatric surgery, gastrointestinal hormones, and the microbiome: An Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) 2022

Background

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) is intended to provide clinicians an overview of bariatric surgery (i.e., bariatric procedures that improve metabolic disease are often termed "metabolic and bariatric surgery"), gastrointestinal hormones, and the microbiome as they relate to patients with obesity.

Methods

The scientific information for this CPS is based upon published scientific citations, clinical perspectives of OMA authors, and peer review by the Obesity Medicine Association leadership.

Results

This CPS includes the pros and cons of the most common types of bariatric procedures; the roles of gastrointestinal (GI) hormones in regulating hunger, digestion, and postabsorptive nutrient metabolism; and the microbiome's function and relationship with body weight. This CPS also describes patient screening for bariatric surgery, patient care after bariatric surgery, and treatment of potential nutrient deficiencies before and after bariatric surgery. Finally, this CPS explores the interactions between bariatric surgery, GI hormones, and the microbiome.

Conclusions

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) regarding bariatric surgery, gastrointestinal hormones, and the microbiome is one of a series of OMA CPSs designed to assist clinicians in the care of patients with the disease of obesity. Implementation of appropriate care before and after bariatric surgery, as well as an awareness of GI hormones and the microbiome, may improve the health of patients with obesity, especially patients with adverse fat mass and adiposopathic metabolic consequences.

Use of Selective Arterial Calcium Stimulation Testing in Identification of Insulinoma in a Patient After Bariatric Surgery

OBJECTIVE

Insulinomas are rare in the post-bariatric surgery setting. The differential diagnosis for hypoglycemia is broad, requiring laboratory testing to verify endogenous hyperinsulinemic hypoglycemia. Selective arterial calcium stimulation testing (SACST) can help localize abnormal insulin production. We describe a patient with histologically confirmed insulinoma after bariatric surgery diagnosed with the aid of SACST.

METHODS

We present a 67 year old woman with a history of Roux-en-Y bypass surgery who presented with endogenous hyperinsulinemic hypoglycemia. Initially, no pancreatic lesion was identified radiologically. We pursued SACST to localize the source of insulin production.

RESULTS

The SACST successfully localized the source of hyperfunctioning islet cells to the pancreatic tail with absolute insulin values in a range consistent with insulinoma. Additional radiologic studies showed a small tumor in the pancreatic tail. Pathology showed a well-differentiated neuroendocrine tumor, compatible with insulinoma.

CONCLUSION

This case study illustrates the usefulness of SACST for the diagnosis and localization of insulinoma.

A Pilot Study of Gut-Brain Signaling After Octreotide Therapy for Unintentional Weight Loss After Esophagectomy

BACKGROUND

Recurrence-free patients after esophageal cancer surgery face long-term nutritional consequences, occurring in the context of an exaggerated postprandial gut hormone response. Acute gut hormone suppression influences brain reward signaling and eating behavior. This study aimed to suppress gut hormone secretion and characterize reward responses and eating behavior among postesophagectomy patients with unintentional weight loss.

METHODS

This pilot study prospectively studied postoperative patients with 10% or greater body weight loss (BWL) beyond 1 year who were candidates for clinical treatment with long-acting octreotide (LAR). Before and after 4 weeks of treatment, gut hormone secretion, food cue reactivity (functional magnetic resonance imaging), eating motivation (progressive ratio task), ad libitum food intake, body composition, and symptom burden were assessed.

RESULTS

Eight patients (7 male, age: mean ± SD 62.8 ± 9.4 years, postoperative BWL: 15.5 ± 5.8%) participated. Octreotide LAR did not significantly suppress total postprandial plasma glucagon-like peptide-1 response at 4 weeks (P = .08). Postprandial symptom burden improved after treatment (Sigstad score median [range]: 12 [2-28] vs 8 [3-18], P = .04) but weight remained stable (pre: 68.6 ± 12.8 kg vs post: 69.2 ± 13.4 kg, P = .13). There was no significant change in brain reward system responses, during evaluation of high-energy or low-energy food pictures, nor their appeal rating. Moreover, treatment did not alter motivation to eat (P = .41) nor ad libitum food intake(P = .46).

CONCLUSION

The protocol used made it feasible to characterize the gut-brain axis and eating behavior in this cohort. Inadequate suppression of gut hormone responses 4 weeks after octreotide LAR administration may explain the lack of gut-brain pathway alterations. A higher dose or shorter interdose interval may be required to optimize the intervention.

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.

Insulinoma Case Admitted with Reactive Hypoglycemia Symptoms

AIM

To present an insulinoma case with post-prandial hypoglycemic symptoms associated with glucose inducible endogenous hyperinsulinemia.

CASE

A 52-year-old female patient was evaluated for hypoglycemic symptoms especially those occuring within 3 hours after consuming sugary foods. These symptoms were persistent for a year and a half. She was diagnosed with reactive (post-prandial) syndrome and followed a recommended diet and was given acarbose but there was no improvement. The results suggested post-prandial endogenous hyperinsulinemia related hypoglycemia. Multiphasic computerized tomography revealed an 11x15x12 mm size mass lesion, anteriorly in the head and uncinate process of the pancreas and then the patients were treated surgically with pancreatic enucleation and cured.

CONCLUSION

Distinguishing post-prandial syndrome by careful history and clinical evaluation in patients with postprandial symptoms is of great importance in terms of cost-effectivity. However, it should not be forgotten that although organic pathologies are mostly presented with fasting hypoglycemia, they may also cause post-prandial symptoms. Severity and progression of the symptoms that point to neuroglycopenia is important, and in this condition the most convenient clinical approach to the patient should be performed with careful and appropriate assessment steps.

Insulin Autoimmune Syndrome (Hirata Disease): A Comprehensive Review Fifty Years After Its First Description

Insulin autoimmune syndrome (IAS), also named Hirata's disease, is a rare condition characterized by hypoglycemic episodes due to the presence of high titers of insulin autoantibodies (IAA). IAS is a form of immune-mediated hypoglycemia, which develops when a triggering factor (ie, a medication or a viral infection) acts on an underlying predisposing genetic background. IAS pathogenesis involves the formation of insulin-IAA complexes that induce glycemic alterations with a double-phase mechanism: IAA prevent insulin to bind its receptor in the postprandial phase, possibly resulting in mild hyperglycemia; thereafter, insulin is released from the complexes irrespective of blood glucose concentrations, thus inducing hypoglycemia. The diagnosis of IAS is challenging, requiring a careful workup aimed at excluding other causes of hyperinsulinemic hypoglycemia. The gold standard for the definitive diagnosis is the finding of IAA in a blood sample. Because IAS is frequently a self-remitting disease, its management mostly consists of supportive measures, such as dietary modifications, aimed at preventing the development of hypoglycemia. Pharmacological therapies may occasionally be necessary for patients presenting with severe manifestations of IAS. Available therapies may include drugs that reduce pancreatic insulin secretion (somatostatin analogues and diazoxide, for instance) and immunosuppressive agents (glucocorticoids, azathioprine and rituximab). The purpose of this review is to provide a comprehensive analysis of the disease, by describing the burden of knowledge that has been obtained in the 50 years following its first description, took in 1970, and by highlighting the points that are still unclear in its pathogenesis and management.

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.

Continuous Glucose Monitoring After Gastric Bypass to Evaluate the Glucose Variability After a Low-Carbohydrate Diet and to Determine Hypoglycemia

BACKGROUND

Roux-en-Y gastric bypass (RYGB) alters glucose metabolism and can cause postprandial hypoglycemia. Continuous glucose monitoring (CGM) has been proposed as an evaluation tool in hypoglycemic RYGB individuals. The objective of this study is to investigate the use of CGM in clinical decision-making including diagnosing hypoglycemia and evaluating treatment effects. Furthermore, we aim to assess its accuracy in RYGB-operated individuals.

METHODS

Thirteen RYGB individuals with symptomatic hypoglycemia and 13 asymptomatic RYGB individuals underwent CGM for 5 days. During this period, a mixed-meal test with concomitant plasma glucose (PG) measurements was performed. Furthermore, the RYGB individuals followed a low-carbohydrate diet (LCD) for 1 day and maintained their ordinary diet (OD) for the rest of the period.

RESULTS

LCD reduced the CGM-determined glycemic variability of the mean interstitial fluid glucose (IFG) significantly compared to OD (p < 0.0001). Receiver operating characteristic analysis confirmed that low blood glucose index (e.g., the frequency and amplitude of hypoglycemic events) is the most reliable parameter related to the development of symptomatic hypoglycemia, with a sensitivity of 0.91 (confidence interval [CI] 0.59; 1.00) and a specificity of 0.77 (CI 0.46; 0.95). However, CGM, measuring the IFG in the subcutaneous adipose tissue, overestimated the minimum glucose levels by 1.1 ± 0.9 mmol/l compared with PG.

CONCLUSIONS

CGM was a good method for demonstrating increased glycemic variability among RYGB individuals and for displaying dietary effects on reducing this glycemic variability, including hypoglycemic events. In RYGB individuals, CGM-measured IFG overestimated the real glucose value by about 1 mmol/l in the hypoglycemic range. This should be taken into consideration if CGM is used to diagnose hypoglycemia after RYGB.

The short- to mid-term symptom prevalence of dumping syndrome after primary gastric-bypass surgery and its impact on health-related quality of life

BACKGROUND

Early and late dumping are complications of gastric bypass surgery. Early dumping occurs within an hour after eating, when the emptying of food into the small intestine triggers rapid fluid shifts into the intestinal lumen and the release of gastrointestinal hormones, resulting in gastrointestinal and vasomotor symptoms. Late dumping occurs between 1 and 3 hours after carbohydrate ingestion and is caused by an exaggerated insulin release, resulting in hypoglycemia. Almost no data are currently available on the prevalence of early and late dumping or their impact on health-related quality of life (QoL).

OBJECTIVES

To study the prevalence of early and late dumping in a large population of patients having undergone a primary Roux-en-Y gastric bypass (RYGB) and its effect on QoL.

SETTING

Cross-sectional study at a single bariatric department in the Medical Center Leeuwarden, The Netherlands between 2008 and 2011.

METHODS

In 2013, this descriptive cohort study approached by email or post all patients who underwent a primary RYGB in the setting between 2008 and 2011 in one hospital. These patients were asked to fill in standardized questionnaires measuring their QoL (RAND-36), anxiety and depression (HADS), fatigue (MFI-20) and any disease specific indicators of early and late dumping syndrome.

RESULTS

The questionnaire was completed and returned by 351 of 613 patients (57.1%) and 121 nonobese volunteers. Participants were mostly female (80%), aged 42 (40-54 years), with an excess weight loss of 76.8% [IQR 61-95] after RYGB surgery 2.3 [ IQR 1.6-3.4] years earlier. Self-reported complaints of moderate to severe intensity suggestive of early and late dumping were present in 18.8% and 11.7% of patients, respectively. Patients with early and late dumping demonstrated significantly lower scores on the RAND-36 and HADS compared with patients without dumping. No differences were seen in the MFI-20 scores between patients with or without early and late dumping.

CONCLUSION

In this descriptive cohort, self-reported complaints suggestive of early and late dumping of moderate-to-severe intensity were, respectively, 18.8% and 11.7% in a cohort after primary gastric bypass surgery. These complaints were associated with markedly reduced health-related QoL.

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.

Evaluation of carbohydrate restriction as primary treatment for post-gastric bypass hypoglycemia

BACKGROUND

Up to 15% of patients who have undergone Roux-en-Y gastric bypass (RYGB) surgery may eventually develop symptoms of hypoglycemia.

OBJECTIVES

To evaluate the daily life efficacy of a carbohydrate (carb)-restricted dietary advice (CRD) of 6 meals per day with a 30 g carb maximum per meal in patients with documented post-RYGB hypoglycemia.

SETTING

Teaching hospital, the Netherlands.

METHODS

Frequency and severity of hypoglycemic events before and after CRD were assessed retrospectively in 41 patients with documented post-RYGB hypoglycemia, based on medical records and telephone questionnaires. Hypoglycemia was defined as a blood glucose level<3.0 mmol/L. Results are expressed as mean values±standard error or median and range.

RESULTS

CRD decreased the number of hypoglycemic events per month from 17.1 (1.5-180) to 2.5 (0-180), i.e., a decline of 85% (P<.001). The lowest blood glucose measured during a hypoglycemic event increased from 2.1±.4 to 2.6±.2 mmol/L (P = .004). The number of patients who had required outside help in the treatment of hypoglycemia, decreased from 23 to 6 (P<.001). In 14 patients (34.1%) the diet-induced reduction of hypoglycemia was insufficient and required the start of insulin suppressive therapy.

CONCLUSION

A CRD, consisting of 6 meals per day with up to 30 g carbs each, is an effective treatment of post-RYGB hypoglycemia in the majority of patients. Additional medication is needed in about a third of 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.

Post-prandial hypoglycemia results from a non-glucose-dependent inappropriate insulin secretion in Roux-en-Y gastric bypassed patients

BACKGROUND

After Roux-en-Y gastric bypass (RYGB), hypoglycemia can occur and be associated with adverse events such as intense malaise and impaired quality of life.

OBJECTIVE

To compare insulin secretion, sensitivity, and clearance between two groups of patients, with or without hypoglycemia, after an oral glucose tolerance test (OGTT 75-g), and also to compare real-life glucose profiles within these two groups.

SETTING

Bariatric surgery referral center.

METHODS

This study involves a prospective cohort of 46 consecutive patients who complained of malaise compatible with hypoglycemia after RYGB, in whom an OGTT 75-g was performed. A plasma glucose value of lower than 2.8 mmol/L (50 mg/dl) between 90 and 120 min after the load was considered to be a significant hypoglycemia. The main outcome measures were insulin sensitivity, beta-cell function, and glycemic profiles during the test. Glucose parameters were also evaluated by continuous glucose monitoring (CGM) in a real-life setting in 43 patients.

RESULTS

Twenty-five patients had plasma glucose that was lower than 2.8 mmol/L between 90 and 120 from the load (HYPO group). Twenty-one had plasma glucose that was higher than 2.8 mmol/L (NONHYPO group). The HYPO patients were younger, had lost more weight after RYGB, were less frequently diabetic before surgery, and displayed higher early insulin secretion rates compared with the NONHYPO patients after the 75-g OGTT, and they had lower late insulin secretion rates. The HYPO patients had lower interstitial glucose values in real life, which suggests that a continuum exists between observations with an oral glucose load and real-life interstitial glucose concentrations.

CONCLUSIONS

This study suggests that HYPO patients after RYGB display an early increased insulin secretion rate when tested with an OGTT. CGM shows that HYPO patients spend more time below 3.3 mmol/L when compared with NONHYPO patients. This phenotype of patients should be monitored carefully after RYGB.

Inpatient Glycemic Protocol for Patients with Diabetes Undergoing Bariatric Surgery

BACKGROUND

Bariatric surgery is a recommended treatment for diabetes in severely obese patients. Their immediate post-operative anti-hyperglycemic requirements differ from other hospitalized diabetics, yet no standardized protocols addressing glycemic control for this group exist.

OBJECTIVE

We aimed to create a safe, easily implemented protocol for immediate post-operative glycemic control, which we defined as the first 30 days.

METHODS

The protocol was designed by an interdisciplinary workgroup using review of available literature, approved institutional glycemic guidelines, and team members' experience with caring for bariatric surgery patients.

RESULTS

Patients are offered post-discharge recommendations using the inpatient glycemic protocol.

CONCLUSION

We designed a protocol with low risk of hypoglycemia that addresses the unique glycemic needs of diabetic bariatric population in the immediate post-operative period.

Effect of carbohydrate restriction in patients with hyperinsulinemic hypoglycemia after Roux-en-Y gastric bypass

BACKGROUND

Hyperinsulinemic hypoglycemia is a rare complication of Roux-en-Y gastric bypass (RYGB) surgery. Meals with a high carbohydrate (carb) content and high glycemic index (GI) may provoke these hypoglycemic attacks. The aim of this study is to assess the effects of reducing meal carb content and GI on glycemic responses in patients with post-RYGB hypoglycemia.

METHODS

Fourteen patients with post-RYGB hypoglycemia underwent two meal tests: a mixed meal test (MMT) with a carb content of 30 g and a meal test with the low GI supplement, Glucerna SR 1.5® (Glucerna meal test (GMT)). Plasma glucose and serum insulin levels were measured for a period of 6 h.

RESULTS

Peak glucose levels were reached at T 30 during GMT and at T 60 during MMT, and they were 1.5 ± 0.3 mmol/L lower during GMT than during MMT (7.5 ± 0.4 vs 9.0 ± 0.4 mmol/L, P < 0.005). GMT induced the most rapid rise in plasma insulin: at T 30 plasma, insulin was 30.7 ± 8.5 mU/L higher during GMT than during MMT (P < 0.005). None of the carb-restricted meals induced post-prandial hypoglycemia.

CONCLUSION

A 30-g carb-restricted meal may help to prevent post-prandial hypoglycemia in patients with post-RYGB hypoglycemia. The use of a liquid, low GI, supplement offers no additional advantage.

Bariatric surgery in class I obesity : a Position Statement from the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO)

Class I obesity conveys an increased risk of comorbidities, impairs physical and mental health-related quality of life, and it is associated to an increased psychosocial burden, particularly in women. The need for effective and safe therapies for class I obesity is great and not yet met by nonsurgical approaches. Eligibility to bariatric surgery has been largely based on body mass index (BMI) cut points and limited to patients with more severe obesity levels. However, obese patients belonging to the same BMI class may have very different levels of health, risk, and impact of obesity on quality of life. Individual patients in class I obesity may have a comorbidity burden similar to, or greater than, patients with more severe obesity. Therefore, the denial of bariatric surgery to a patient with class I obesity suffering from a significant obesity-related health burden and not achieving weight control with nonsurgical therapy simply on the basis of the BMI level does not appear to be clinically justified. A clinical decision should be based on a more comprehensive evaluation of the patient's current global health and on a more reliable prediction of future morbidity and mortality. After a careful review of available data about safety and efficacy of bariatric surgery in patients with class I obesity, this panel reached a consensus on ten clinical recommendations.

Glucose regulation and cognitive function after bariatric surgery

INTRODUCTION

Obesity is associated with cognitive impairment, and bariatric surgery has been shown to improve cognitive functioning. Rapid improvements in glycemic control are common after bariatric surgery and likely contribute to these cognitive gains. We examined whether improvements in glucose regulation are associated with better cognitive function following bariatric surgery.

METHOD

A total of 85 adult bariatric surgery patients underwent computerized cognitive testing and fasting blood draw for glucose, insulin, and glycated hemoglobin (HbA1c) at baseline and 12 months postoperatively.

RESULTS

Significant improvements in both cognitive function and glycemic control were observed among patients. After controlling for baseline factors, 12-month homeostatic model assessment of insulin resistance HOMA-IR predicted 12-month digits backward (β = -.253, p < .05), switching of attention-A (β = .156, p < .05), and switching of attention-B (β = -.181, p < .05). Specifically, as HOMA-IR decreased over time, working memory, psychomotor speed, and cognitive flexibility improved. Decreases in HbA1c were not associated with postoperative cognitive improvements. After controlling for baseline cognitive test performance, changes in body mass index (BMI) were also not associated with 12-month cognitive function.

CONCLUSIONS

Small effects of improved glycemic control on improved aspects of attention and executive function were observed following bariatric surgery among severely obese individuals. Future research is needed to identify the underlying mechanisms for the neurocognitive benefits of these procedures.

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.

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.

Reversible Adrenal Insufficiency in Three Patients With Post-Roux-en-Y Gastric Bypass Noninsulinoma Pancreatogenous Hypoglycemia Syndrome

Objective. Noninsulinoma pancreatogenous hypoglycemia syndrome (NIPHS) is a disorder of endogenous hyperinsulinemia that is clinically distinguishable from insulinoma, with a greater preponderance after Roux-en-Y gastric bypass (RYBG). Hyperinsulinemic hypoglycemia can predispose to attenuation of counterregulatory hormone responses to hypoglycemia, and consequent suppression of the hypothalamic-pituitary-adrenal (HPA) axis. This case series describes 3 individuals who were diagnosed with adrenal insufficiency (AI) after undergoing RYGB, complicated by NIPHS. Methods. A retrospective chart review was performed for each individual. Chart review applied particular attention to the onset of hyperinsulinemic hypoglycemia following bariatric surgery and the dynamic testing leading to the diagnoses of NIPHS and AI. Results. In each case, reactive hypoglycemia ensued within months to years after RYGB. Cosyntropin stimulation testing confirmed the diagnosis of AI. Hydrocortisone therapy reduced the frequency and severity of hypoglycemia and was continued until successful medical and/or surgical management of hyperinsulinism occurred. Follow-up testing of the HPA axis demonstrated resolution of AI. In all cases, hydrocortisone therapy was finally discontinued without incident. Conclusion. We speculate that transient AI is a potential complication in patients who experience recurrent hyperinsulinemic hypoglycemia after RYGB. The putative mechanism for this observation may be attenuation of the HPA axis after prolonged exposure to severe, recurrent hypoglycemia. We conclude that biochemical screening for AI should be considered in individuals who develop post-RYGB hyperinsulinemic hypoglycemia. If AI is diagnosed, supportive treatment should be maintained until hyperinsulinemic hypoglycemia has been managed effectively.

Post-gastric-bypass hypoglycemia successfully treated with alpha-glucosidase inhibitor therapy

OBJECTIVE

To review the effectiveness of alpha-glucosidase inhibitor (AGI) therapy in the treatment of hypoglycemia after Roux-en-y gastric surgery.

METHODS

Retrospective case review.

RESULTS

Four patients who previously underwent Roux-en-y gastric bypass were evaluated because of severe symptomatic postprandial hypoglycemia that was unresponsive to a low-carbohydrate diet. Mixed-meal testing confirmed hyperinsulinemia. Other causes of hypoglycemia were ruled out by a combination of clinical examination, endocrine testing, and computed tomography imaging. Symptomatic hypoglycemia resolved in all 4 patients after AGI therapy was started. One patient could not tolerate long-term therapy because of a rash. The other 3 patients were followed for between 5 and 48 months and remained free of symptomatic postprandial hypoglycemia.

CONCLUSION

AGI therapy is effective in the long-term treatment of post-Roux-en-y hypoglycemia in patients unresponsive to a low-carbohydrate diet. To our knowledge, this is the first report documenting the long-term usefulness of this therapy in a series of patients.

Postprandial hyperinsulinemic hypoglycemia after gastric bypass surgical treatment

An association between post-Roux-en-Y gastric bypass (RYGB) hypoglycemia and nesidioblastosis was reported in 2005 and may cause serious neuroglycopenic symptoms. Most patients with postprandial hypoglycemia after RYGB respond to nutritional and medical treatment. A subset of patients, however, may not respond adequately and surgery may be considered. This review describes the current experience with surgical intervention for severe post-RYGB hypoglycemia. PubMed and MEDLINE searches were made for reports describing clinical outcome after such surgery. Fourteen papers including 75 patients were identified. Different surgical interventions were applied including gastric tube placement, reversal of the bypass with and without concomitant sleeve resection, gastric pouch restriction, and pancreatic resection and reresection. Pancreatic resection was performed in 51 (68%) patients, 17 (23%) had RYGB reversal and eleven (15%) had gastric pouch restriction alone. Eight (11%) patients received 2 or more consecutive procedures for hypoglycemia and combined interventions were made in several patients. Resolution of the symptoms occurred in 34/51 (67%) patients after pancreatic resection, 13/17 (76%) after reversal, and 9/11 (82%) after pouch restriction. Mean follow up, however, was short for most series and the methods applied for evaluation of hypoglycemia varied. Weight regain, diabetes and recurrent symptoms were late complications. The optimal therapy for hypoglycemia after RYGB is not defined. Long-term evaluations and knowledge about the physiology of post-RYGB hypoglycemia, may enable therapy with improved control of the glucose excursions.

Exaggerated release and preserved insulinotropic action of glucagon-like peptide-1 underlie insulin hypersecretion in glucose-tolerant individuals after Roux-en-Y gastric bypass

AIMS/HYPOTHESIS

Roux-en-Y gastric bypass (RYGB) improves glycaemic control in part by increasing postprandial insulin secretion through exaggerated glucagon-like peptide (GLP)-1 release. However, it is unknown whether islet cell responsiveness to i.v. glucose, non-glucose (arginine) and incretin hormones, including GLP-1, is altered.

METHODS

Eleven severely obese glucose-tolerant individuals underwent three hyperglycaemic clamps with arginine bolus and co-infusion of either GLP-1, glucose-dependent insulinotropic polypeptide (GIP) or saline before, and at 1 week and 3 months after RYGB. In addition, an OGTT was performed before and 3 months after surgery.

RESULTS

After RYGB, insulin sensitivity improved at 1 week and 3 months, while insulin stimulation and glucagon suppression in response to the clamp with saline co-infusion were largely unaltered. The influence of i.v. GLP-1 and GIP on insulin and glucagon secretion was also unchanged postoperatively. In response to the postoperative OGTT at 3 months, insulin and GLP-1, but not GIP, secretion increased. Furthermore, the glucose profile during the OGTT was altered, with a substantial reduction in 2 h plasma glucose and a paradoxical hypersecretion of glucagon.

CONCLUSIONS/INTERPRETATION

After RYGB, insulin hypersecretion is linked to the oral, but not the i.v., route of administration and is associated with exaggerated release and preserved insulinotropic action of GLP-1, while both the secretion and action of GIP are unchanged. The results highlight the importance of increased GLP-1 secretion for improving postoperative glucose metabolism.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01559779.

Upper gastrointestinal symptoms in obese patients and their outcomes after bariatric surgery

Obesity is considered an important risk factor for the development of gastrointestinal (GI) disorders, likely through alterations of GI motility. Even though gastroesophageal reflux disease is the condition mainly studied at present, the prevalence of other upper GI symptoms is also augmented in obese patients. Owing to their chronic trend, these disorders have a bearing on public spending and their correct diagnosis would avoid unnecessary cost-consuming investigations. Furthermore, bariatric surgery dramatically changes GI anatomy and physiology, influencing GI symptom outcomes. The aim of this review is to categorize the available results in a pathophysiological framework in an attempt to set up the correct clinical GI management of obese patients before and after bariatric surgery. This would be helpful in tentatively reducing their considerable economic burden on public health services.

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

BACKGROUND

About 70% of the patients operated on for a gastric bypass (Roux-en-Y gastric bypass [RYGB]) suffer from dumping syndrome. In these patients, previous studies have demonstrated a high glycemic variability with hypoglycemia and with altered continuous glucose monitoring (CGM) profiles. The aim of this study was to evaluate the effect of treatment with dietary counseling plus acarbose administration on the symptoms and on the characteristics of the CGM profile.

SUBJECTS AND METHODS

Eight consecutive patients with dumping syndrome were given dietary counseling for 6 weeks and also treated with acarbose (50-100 mg three times a day). Their symptoms and the features of the CGM were compared before and after treatment.

RESULTS

The symptoms disappeared in seven patients. There was a significant increase in the time to the interstitial glucose (IG) peak and a reduction in the rate of the IG increase after a meal and in the rate of the IG decrease following the peak. The time below 60 mg/dL was significantly decreased, and the minimal IG value was significantly increased. The maximum and mean IG levels and the time above 140 mg/dL were decreased, but not significantly. Six patients spent more than 1% of the time with IG values below 60 mg/dL before treatment, but after treatment this was reduced to one patient. Before treatment only one patient had an IG level neither below 60 or above 140 mg/dL, and after treatment four patients were in this category.

CONCLUSIONS

Dietary counseling and acarbose treatment eliminated the symptoms and improved the CGM profile of patients suffering from dumping syndrome after RYGB.

Bariatric surgery for type 2 diabetes

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

[Obesity surgery and its adverse effects]

Bariatric surgery (gastric banding, gastric bypass, sleeve gastrectomy, bilio-pancreatic diversion) is the most efficient long-term treatment concerning weight loss, comorbidities and quality of life improvement, and mortality reduction for massive obesity and complicated obesity. These benefits need to be compared to immediate and late adverse events. The adverse events involve operative risk, surgical, nutritional, and sometimes psychological events. This review describes the various surgical techniques and their complications. Then, it discusses the modalities to prepare, follow-up and take care of these surgical patients to improve the results and avoid the complications.