Why it matters. A paired editorial for “Hypoglycemia after Roux-en-Y gastric bypass: detection rates of continuous glucose monitoring (CGM) versus mixed meal test”

Canakinumab for the treatment of postprandial hypoglycaemia: study protocol for a randomised, placebo-controlled, parallel-group, double-blind, multicentric, superiority trial-the CanpHy study

INTRODUCTION

Postbariatric hypoglycaemia (PBH) is a complex medical condition with a significant impact on patients' quality of life. The underlying mechanisms remain to be elucidated. We have shown that food ingestion increases IL-1β and subsequently stimulates insulin secretion. We therefore hypothesised that overactivation of the IL-1β pathway could lead to PBH by promoting excessive insulin secretion after a meal. In a proof-of-concept study, we have shown that acute treatment with the IL-1 receptor antagonist anakinra can attenuate PBH after a single liquid mixed meal. This study aims to validate this therapeutic approach over a longer period of time using the long-acting anti-IL-1β antibody canakinumab.

METHODS AND ANALYSIS

In this prospective, randomised, double-blind, placebo-controlled, multicentre trial, we plan to enrol 62 adult patients after bariatric surgery with frequent, postprandial hypoglycaemia (ie, <3.0 mmol/L and at least five hypoglycaemic episodes per week). Eligible subjects will be randomised to receive either single-dose 150 mg canakinumab (Ilaris, Novartis) subcutaneously (s.c.) or matched placebo (1.0 mL physiologic saline). For 28 days, patients are required to wear a blinded continuous glucose monitoring device (CGMS, Dexcom G6) and use a diary to track their hypoglycaemic episodes. Primary outcomes include health-related quality of life, measured by the SF-36, as well as postprandial hypoglycaemic events (glucose <3.0 mmol/L). A significant improvement in any one of these outcomes will be considered sufficient to demonstrate the clinical superiority of canakinumab over placebo. Secondary outcomes include patient-oriented measures such as postprandial hypoglycaemic symptoms, hypoglycaemia unawareness, fear of hypoglycaemia, as well as metabolic measures and safety assessments.

ETHICS AND DISSEMINATION

The trial was approved by the Cantonal Ethics Committee 'Ethikkommission Nordwest- und Zentralschweiz' in January 2022 (#2021-02325), as well as by Swissmedic in April 2022 (#701280). Current, approved protocol version 1.3 of 28.03.2023. The study is actively recruiting. Results will be published in a relevant scientific journal and communicated to participants and relevant institutions through dissemination activities. Individual data are accessible on request.

TRIAL REGISTRATION

The study is registered with the www.

CLINICALTRIALS

gov registry (NCT05401578) and the Swiss National Clinical Trials Portal (SNCTP) on www.kofam.ch (SNCTP000004838).

Symptomatic Hypoglycemia After Gastric Bypass: Incidence and Predictive Factors in a Cohort of 1,138 Consecutive Patients

OBJECTIVE

After Roux-en-Y gastric bypass (RYGB), postprandial hyperinsulinemic hypoglycemia (PPHH) is particularly critical because of the risk of trauma. The aim of this study was to assess the incidence and identify risk factors for symptomatic PPHH.

METHODS

Patients with RYGB were classified into moderate PPHH (MH) or severe hypoglycemia (SH), which is defined as patients with neuroglycopenic symptoms. Logistic multivariate linear regressions were performed to identify predictive factors for symptomatic PPHH and more specifically for SH with neuroglycopenic symptoms. Patients with diabetes and those with a follow-up shorter than 2 years were excluded.

RESULTS

Among the 1,138 patients, 44.2% had at least one episode of hypoglycemia with a mean delay of 25.5 (21.3) months, 32.6% had MH, and 11.6% had SH. The annual incidence rate of SH was 2.5% the first year, 3.7% the second year, and 1.5% the third year. Independent predictive factors for higher risk of SH were: younger age (odds ratio [OR] = 1.01; 95% CI: 1.05-16.69; P = 0.0007), lower BMI after RYGB (OR = 1.61; 95% CI: 1.17-2.22; P = 0.0035), and maximal weight loss (OR = 1.04; 95% CI = 1.39-1.23; P = 0.0106), whereas higher preoperative BMI was protective (OR = 0.78; 95% CI: 0.64-0.95; P = 0.0112).

CONCLUSIONS

This observational cohort study showed that the incidence of severe PPHH with neuroglycopenic symptoms after RYGB was higher than expected.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prevalence of Dumping Syndrome After Laparoscopic Sleeve Gastrectomy and Comparison with Laparoscopic Roux-en-Y Gastric Bypass

BACKGROUND

Dumping syndrome is a well-known side effect of laparoscopic gastric bypass (LRYGB), and it is commonly believed that dumping syndrome is less likely to occur after laparoscopic sleeve gastrectomy (LSG), due to the preservation of the pyloric sphincter. However, it is not uncommon for patients undergoing LSG at our center to report symptoms suggestive of dumping syndrome.

OBJECTIVE

To assess the prevalence of symptoms of dumping syndrome after LSG compared with LRYGB.

SETTING

A single surgical group at a high-volume (700 cases per year) Bariatric and Metabolic Surgery Center of Excellence.

METHODS

One thousand four hundred seventy-one LRYGB (366) and LSG (1105) patients received a questionnaire to assess symptoms of dumping syndrome, utilizing a modified version of the Sigstad scoring system. Dumping syndrome was considered to be present when the questionnaire score exceeded a threshold value.

RESULTS

A total of 360 responses were received (249 LSG, 111 LRYGB). 26.5% (66) LSG and 41.4% (46) LRYGB exceeded the threshold for dumping syndrome (p < 0.01). 84.8% (56) LSG and 84.7% (39) LRYGB reported early dumping syndrome (p > 0.05). Thirty-six percent (24) LSG and 28% (13) LRYGB reported late dumping syndrome (p > 0.05). Twenty-seven percent (62) LSG and 44.4% (44) LRYGB reported at least one symptom of dumping syndrome with sweets (p < 0.05). 34.3% (85) LSG and 35.5% (39) LRYGB reported symptoms when drinking with or within 30 min of a meal (p > 0.05). 14.5% (36) LSG and 17.3% (19) LRYGB reported symptoms after alcohol consumption (p > 0.05).

CONCLUSION

Dumping syndrome after LSG is prevalent but has not been widely reported. This finding may impact clinicians and patients in their choice of procedure and has relevance in post-operative education and care.

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.

Prevalence, severity, and predictors of symptoms of dumping and hypoglycemia after Roux-en-Y gastric bypass

BACKGROUND

Roux-en-Y gastric bypass (RYGB) results in pronounced weight loss in morbidly obese patients but may also cause adverse effects like early dumping and hypoglycemia. Prevalence data on these complications and their potential predictors are sparse.

OBJECTIVE

To assess the prevalence and possible predictors of early dumping and hypoglycemia in a population-based cohort of RYGB patients.

SETTING

University Hospital, Denmark.

DESIGN

A questionnaire survey was performed in the Central Denmark Region including RYGB-operated patients (years 2006-2011, n = 2238) and a nonoperated comparison cohort (n = 89). The Dumping Rating Scale and the Edinburgh Hypoglycemia Scoring System, together with demographic and clinical characteristics, were used, and possible predictors were examined by logistic regression.

RESULTS

The response rate was 64% (1429/2238). In total, 9.4% (134/1429) and 6.6% (95/1429) experienced moderate or severe symptoms of early dumping and hypoglycemia, respectively, which were significantly higher than in the comparison cohort. Because 3.4% (95% CI: 2.5-4.4) of the RYGB group experienced both early dumping and hypoglycemia, the total prevalence of 1 or both conditions was 12.6 (95% CI 10.9-14.4). Possible predictors for both conditions were body mass index (BMI)<25 kg/m² (odds ratio [OR] 1.70 (95% CI: 0.98-2.95) and OR 1.60 (95% CI: .83-3.06), respectively) compared with patients with BMI 25-30 kg/m². Younger age seemed to increase the risk of both conditions (<35 yr: OR 1.75 (95% CI: 1.11-2.75) and OR .59 (95% CI: .93-2.72), respectively) compared with patients>45 years.

CONCLUSION

Symptoms of early dumping and hypoglycemia were rather common with a prevalence of 1 or both conditions of 12.6% after RYGB. Predictors included younger age and a lower BMI.

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.