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

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

BACKGROUND AND AIMS

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

The effects of postprandial exercise and meal glycemic index on plasma glucose and glucoregulatory hormone responses after Roux-en-Y gastric bypass

Postprandial hypoglycemia is a complication of Roux-en-Y gastric bypass (RYGB), but the effects of postprandial exercise and meal glycemic index (GI) on postprandial glucose and glucoregulatory hormone responses are unknown. Ten RYGB-operated and 10 age and weight-matched unoperated women completed four test days in random order ingesting mixed meals with high GI (HGI, GI = 93) or low GI (LGI, GI = 54), but matched on energy and macronutrient content. Ten minutes after meal completion, participants rested or cycled for 30 min at 70% of maximum oxygen uptake (V̇o2max). Blood was collected for 4 h. Postprandial exercise did not lower plasma nadir glucose in RYGB after HGI (HGI/rest 3.7 ± 0.5 vs. HGI/Ex 4.1 ± 0.4 mmol/L, P = 0.070). Replacing HGI with LGI meals raised glucose nadir in RYGB (LGI/rest 4.1 ± 0.5 mmol/L, P = 0.034) and reduced glucose excursions (Δpeak-nadir) but less so in RYGB (-14% [95% CI: -27; -1]) compared with controls (-33% [-51; -14]). Insulin responses mirrored glucose concentrations. Glucagon-like peptide 1 (GLP-1) responses were greater in RYGB versus controls, and higher with HGI versus LGI. Glucose-dependent insulinotropic polypeptide (GIP) responses were greater after HGI versus LGI in both groups. Postexercise glucagon responses were lower in RYGB than controls, and noradrenaline responses tended to be lower in RYGB, whereas adrenaline responses were similar between groups. In conclusion, moderate intensity cycling shortly after meal intake did not increase the risk of postprandial hypoglycemia after RYGB. The low GI meal increased nadir glucose and reduced glucose excursions compared with the high GI meal. RYGB participants had lower postexercise glucagon responses compared with controls.NEW & NOTEWORTHY We investigate the effect of moderate exercise after a high or a low glycemic index meal on nadir glucose and glucoregulatory hormones in gastric bypass-operated individuals and in matched unoperated controls. Cycling shortly after meal intake did not increase the risk of hypoglycemia in operated individuals. The low glycemic index meal increased glucose nadir and reduced excursions compared with the high glycemic index meal. Operated individuals had lower postexercise glucagon responses compared with controls.

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.

Preliminary prospective study of real-time post-gastrectomy glycemic fluctuations during dumping symptoms using continuous glucose monitoring

BACKGROUND

Although dumping symptoms constitute the most common post-gastrectomy syndromes impairing patient quality of life, the causes, including blood sugar fluctuations, are difficult to elucidate due to limitations in examining dumping symptoms as they occur.

AIM

To investigate relationships between glucose fluctuations and the occurrence of dumping symptoms in patients undergoing gastrectomy for gastric cancer.

METHODS

Patients receiving distal gastrectomy with Billroth-I (DG-BI) or Roux-en-Y reconstruction (DG-RY) and total gastrectomy with RY (TG-RY) for gastric cancer (March 2018-January 2020) were prospectively enrolled. Interstitial tissue glycemic profiles were measured every 15 min, up to 14 d, by continuous glucose monitoring. Dumping episodes were recorded on 5 patient-selected days by diary. Within 3 h postprandially, dumping-associated glycemic changes were defined as a dumping profile, those without symptoms as a control profile. These profiles were compared.

RESULTS

Thirty patients were enrolled (10 DG-BI, 10 DG-RY, 10 TG-RY). The 47 early dumping profiles of DG-BI showed immediately sharp rises after a meal, which 47 control profiles did not (P < 0.05). Curves of the 15 late dumping profiles of DG-BI were similar to those of early dumping profiles, with lower glycemic levels. DG-RY and TG-RY late dumping profiles (7 and 13, respectively) showed rapid glycemic decreases from a high glycemic state postprandially to hypoglycemia, with a steeper drop in TG-RY than in DG-RY.

CONCLUSION

Postprandial glycemic changes suggest dumping symptoms after standard gastrectomy for gastric cancer. Furthermore, glycemic profiles during dumping may differ depending on reconstruction methods after gastrectomy.

Predictors of Postprandial Hypoglycemia After Gastric Bypass Surgery: a Retrospective Case-Control Study

Background

Postprandial hypoglycemia after bariatric surgery is an exigent disorder, often impacting the quality of life. Distinguishing clinically relevant hypoglycemic episodes from symptoms of other origin can be challenging. Diagnosis is demanding and often requires an extensive testing such as prolonged glucose tolerance or mixed-meal test. Therefore, we investigated whether baseline parameters of patients after gastric bypass with suspected hypoglycemia can predict the diagnosis.

Methods

We analyzed data from 35 patients after gastric bypass with suspected postprandial hypoglycemia and performed a standardized mixed-meal test. Hypoglycemia was defined by the appearance of typical symptoms, low plasma glucose, and relief of symptoms following glucose administration. Parameters that differed in patients with and without hypoglycemia during MMT were identified and evaluated for predictive precision using receiver operating characteristic (ROC) areas under the curve (AUC).

Results

Out of 35 patients, 19 (54%) developed symptomatic hypoglycemia as a result of exaggerated insulin and C-peptide release in response to the mixed-meal. Hypoglycemic patients exhibited lower glycosylated hemoglobin A1c (HbA_1c) and higher absolute and relative weight loss from pre-surgery to study date. HbA1c and absolute weight loss alone could achieve acceptable AUCs in ROC analyses (0.76 and 0.72, respectively) but a combined score of absolute weight loss divided by HbA1c (0.78) achieved the best AUC.

Conclusions

HbA1c and weight loss differed in patients with and without symptomatic hypoglycemia during mixed-meal test. These baseline parameters could be used for screening of postprandial hypoglycemia in patients after gastric bypass and may facilitate the selection of patients requiring further evaluation.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11695-021-05277-1.

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.

Mechanisms of action of a carbohydrate-reduced, high-protein diet in reducing the risk of postprandial hypoglycemia after Roux-en-Y gastric bypass surgery

BACKGROUND

Postprandial hypoglycemia is a risk after Roux-en-Y gastric bypass (RYGB).

OBJECTIVES

We speculated that a carbohydrate-reduced, high-protein (CRHP) diet might reduce the risk of hypoglycemia and therefore compared the acute effects of a conventionally recommended (CR) diet and CRHP diet [55/30 energy percent (E%) carbohydrate and 15/30 E% protein, respectively] in RYGB patients.

METHODS

Ten individuals (2 males, 8 females, mean ± SD age 47 ± 7 y; stable body mass index 31 ± 6 kg/m2; 6 ± 3 y post-RYGB) with recurrent postprandial hypoglycemia documented by plasma glucose (PG) ≤3.4 mmol/L were examined on 2 d with isoenergetic CRHP or CR diets comprising a breakfast and subsequent lunch meal.

RESULTS

Peak PG was significantly reduced on the CRHP diet after breakfast and lunch by 11% and 31% compared with the CR diet. Nadir PG increased significantly on CRHP (by 13% and 9%). Insulin secretion was reduced, and glucagon secretion increased on the CRHP diet after both meals. Glucagon-like peptide 1 and glucose-dependent insulinotropic polypeptide secretion were lower after lunch but unaltered after breakfast on CRHP; β-cell function and insulin clearance were unchanged.

CONCLUSIONS

The CRHP diet lowered glucose excursions and reduced insulin secretion and incretin hormone responses, but enhanced glucagon responses compared with the CR diet. Taken together, the results may explain the decreased glucose variability and lower risk of postprandial hypoglycemia. This study was registered at clinicaltrials.gov as NCT02665715.

Prevalence of hypoglycaemia in a random population after Roux-en-Y gastric bypass after a meal test

OBJECTIVE

Roux-en-Y gastric bypass (RYGB) is an effective way to induce sustainable weight loss and can be complicated by postprandial hyperinsulinaemic hypoglycaemia (PHH). To study the prevalence and the mechanisms behind the occurrence of hypoglycaemia after a mixed meal tolerance test (MMTT) in patients with primary RYGB.

DESIGN

This is a cross-sectional study of patients 4 years after primary RYGB.

METHODS

From a total population of 550 patients, a random sample of 44 patients completed the total test procedures. A standardized mixed meal was used as stimulus. Venous blood samples were collected at baseline, every 10 min during the first half hour and every 30 min until 210 min after the start. Symptoms were assessed by questionnaires. Hypoglycaemia is defined as a blood glucose level below 3.3 mmol/L.

RESULTS

The prevalence of postprandial hypoglycaemia was 48% and was asymptomatic in all patients. Development of hypoglycaemia was more frequent in patients with lower weight at surgery (P = 0.045), with higher weight loss after surgery (P = 0.011), and with higher insulin sensitivity calculated by the homeostasis model assessment indexes (HOMA2-IR, P = 0.014) and enhanced beta cell function (insulinogenic index at 20 min, P = 0.001).

CONCLUSION

In a randomly selected population 4 years after primary RYGB surgery, 48% of patients developed a hypoglycaemic event during an MMTT without symptoms, suggesting the presence of hypoglycaemia unawareness in these patients. The findings in this study suggest that the pathophysiology of PHH is multifactorial.

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

BACKGROUND

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

OBJECTIVES

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

SETTING

Sahlgrenska University Hospital, Sweden.

METHODS

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

RESULTS

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

CONCLUSIONS

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

Hypoglycemia Following Bariatric Surgery: Our 31-Year Experience

PURPOSE

The purposes of this study are to identify the cumulative incidence of post-bariatric surgery hypoglycemia (PBSH), describe its symptomatology, and characterize treatment patterns at a large academic institution.

MATERIALS AND METHODS

All patients who underwent bariatric surgery at a single institution from 1985 to 2015 were identified using a clinical database, administrative billing data identified patients who were treated for hypoglycemia, and chart reviews were performed to make a diagnosis of PBSH based on Whipple's triad. PBSH cases were reviewed including patient diabetes history, symptomatology, and treatment measures. Univariate analyses were performed to identify correlations based on symptomatology, laboratory values, and treatments utilized.

RESULTS

Ninety (2.6%) of 3487 patients were diagnosed with PBSH with preoperative median age of 43 years, mean BMI of 50.0 kg/m², and median glycated hemoglobin of 6.0%. Median time-to-first hypoglycemic event was 40.6 months. No factors were identified which predict symptom severity or resolution. The 24 (27%) patients who received pharmacotherapy to treat hypoglycemia were younger, had lower nadir blood glucose levels, and more frequent symptoms. Sixty-nine (79%) cases eventually resolved.

CONCLUSIONS

PBSH onset and severity are highly variable. Successful management of these patients can prove difficult and should include dietary therapy, the selective use of pharmacotherapy and surgery, and the use of a multidisciplinary team including bariatric surgeons and endocrinologists.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Surgery-related gastrointestinal symptoms in a prospective study of bariatric surgery patients: 3-year follow-up

BACKGROUND

Having accurate information on bariatric surgery-related gastrointestinal (GI) symptoms is critical for patient care.

OBJECTIVE

To report on surgery-related GI symptoms over the first 3 years following Roux-en-Y gastric bypass and laparoscopic adjustable gastric band.

SETTING

Three academic medical centers in the United States.

METHODS

As a substudy of the Longitudinal Assessment of Bariatric Surgery Consortium, 183 participants (pre-surgery median body mass index = 45.1 kg/m²; median age = 46 yr; 83.1% female). completed the Eating Disorder Examination-Bariatric Surgery Version interview at≥1 annual assessment. Patients self-reported frequency of dysphagia, dumping syndrome, and spontaneous vomiting.

RESULTS

Prevalence of dysphagia at least once weekly decreased post-laparoscopic adjustable gastric band surgery from 43.9% (95% confidence interval [CI], 32.2-55.6) in year 1 to 27.5% (95% CI, 15.2-39.9) in year 3 (P = .02). Dysphagia and dumping at least once weekly also appeared to decrease in years 1-3 post-Roux-en-Y gastric bypass (i.e., from 16.7% [95% CI, 9.4-24.1] to 10.9% [95% CI, 4.0-17.8] and from 9.9% [95% CI, 4.3-15.5] to 6.3% [95% CI, 1.7-10.9], respectively), but power was limited to evaluate trends. Vomiting at least once weekly was rare (<6%) in years 1-3 following both procedures. Controlling for potential confounders and surgical procedure, loss of control eating at least once weekly was associated with higher risk of at least once weekly dysphagia (relative risk = 2.01, 95% CI, 1.36-2.99, P = .001).

CONCLUSIONS

The prevalence of bariatric surgery-related GI symptoms appears to decrease across follow-up. Symptoms were associated with loss of control eating, suggesting a target for clinical intervention.

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.

Overall and cause-specific mortality after Roux-en-Y gastric bypass surgery: A nationwide cohort study

BACKGROUND

Few population-based studies provide data on mortality after bariatric surgery. We hypothesized that hypoglycemia could be an underdiagnosed cause of death.

OBJECTIVES

To examine perioperative, all-cause, and cause-specific long-term mortality in Roux-en-Y gastric bypass (RYGB) patients versus population comparisons.

SETTING

Danish nationwide population-based cohort study.

METHODS

We included all 9895 patients who underwent RYGB during 2006-2010, and a 1:25 age- and gender-matched comparison cohort (n = 247,366) (0.3% lost to follow up). We compared mortality rates and computed mortality rate ratios (MRR) for all-cause and cause-specific mortality using Cox regression analysis. For deceased RYGB patients (n = 91), we conducted a detailed medical record audit.

RESULTS

The perioperative (30-days) mortality after RYGB was .04% (4/9895). After 4.2 years, RYGB-related mortality (deaths due to intestinal obstruction/intra-abdominal leakage) was .15% (16/9895). All-cause mortality was very similar in the 2 cohorts (median age, 40.2 years; 21.7% men): RYGB cohort, .89% (n = 91); comparison cohort, .92% (n = 2204); MRR = 1.03 (95% confidence interval [CI], .84-1.27). Mortality due to suicide (2.78; 95% CI, 1.44-5.33), accidents (2.29; 95% CI, 1.16-4.54), gastrointestinal diseases (2.01; 95% CI, 1.06-3.84), and infectious diseases (1.75; 95% CI, .98-3.17) was higher in the RYGB cohort versus comparison groups, but mortality from cancer was lower (0.43; 95% CI, .27-.70). Our medical record audit indicated that 8% of deaths after RYGB (n = 7) were possibly hypoglycemia related.

CONCLUSION

Perioperative mortality after RYGB is low in Denmark, and subsequent all-cause mortality is similar to that of matched comparisons. After RYGB, patients have substantially increased mortality due to external causes such as suicide, accidents, and possibly hypoglycemia.

Early dumping syndrome is not a complication but a desirable feature of Roux-en-Y gastric bypass surgery

Early dumping syndrome after gastric bypass surgery due to rapid delivery of hyperosmolar nutrients into the bowel causing intense symptoms is often described as a complication. Twelve patients, mean age 47 years, were interviewed approximately 9 years post-operation. The interviews were audiotaped and transcribed verbatim, followed by an inductive content analysis to reveal patients' experience of the dumping syndrome. The core category 'Dumping syndrome is a positive consequence of Roux-en-Y gastric bypass surgery and a tool to control food intake' was identified based on the following four sub-categories: (i) 'The multidimensional emergence and effects of dumping syndrome', (ii) 'Dumping syndrome as something positive although unpleasant', (iii) 'Developing coping mechanisms and ingenious strategies' and (iv) 'My own fault if I expose myself to dumping syndrome'. From the patients' perspective, dumping syndrome gives control over food intake; although the symptoms were unpleasant, patients considered dumping syndrome as a positive protection against over-consumption. Hence, healthcare professionals should not present dumping syndrome as a complication but rather as an aid to control eating behaviour and excessive food intake.

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.

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.

Insulin response to oral stimuli and glucose effectiveness increased in neuroglycopenia following gastric bypass

OBJECTIVE

Hyperinsulinemic hypoglycemia with neuroglycopenia is a rare complication following Roux-en-Y gastric bypass (RYGB) surgery for weight management. Insulin secretion and action in response to oral and intravenous stimuli in persons with and without neuroglycopenia following RYGB are evaluated in this study.

METHODS

Cross-sectional cohort studies were performed at a single academic institution to assess insulin secretion and action during oral mixed meal tolerance test and intravenous glucose tolerance test (IVGTT).

RESULTS

Insulin secretion was increased more following oral mixed meal than intravenous glucose in individuals with neuroglycopenia compared to the asymptomatic group. Reduced insulin clearance did not contribute to higher insulinemia. Glucose effectiveness at zero insulin, estimated during the IVGTT, was also higher in those with neuroglycopenia. Insulin sensitivity did not differ between groups.

CONCLUSIONS

Increased beta-cell response to oral stimuli and insulin-independent glucose disposal may both contribute to severe hypoglycemia after RYGB.