Hypoglycemia and Dysautonomia After Bariatric Surgery: a Systematic Review and Perspective

Defining Clinical Characteristics of Individuals With and Without Post-Bariatric Hypoglycemia After Gastric Bypass

CONTEXT

Post-bariatric hypoglycemia (PBH) is a complication of bariatric surgery including Roux-en-Y gastric bypass (RYGB). It remains unclear why only some individuals develop PBH.

OBJECTIVE

To identify clinical characteristics distinguishing post-RYGB individuals with PBH, versus without symptomatic hypoglycemia (RYGB non-hypo).

DESIGN AND SETTING

Cross-sectional observational study in academic referral centre. Adults 18-70, without current diabetes, were recruited into three groups: (1) PBH (n = 39); (2) RYGB non-hypo (n = 25); and (3) individuals without history of upper gastrointestinal surgery (n = 17). Outcome measures included between-group differences in medical history and medication use, and survey-based scores for hypoglycemia, dumping syndrome, and autonomic symptoms.

RESULTS

PBH participants were 92% female, age 53.4 ± 11.9 y, BMI 31.2 ± 5.6 kg/m2, versus RYGB non-hypo (100% female, age 53.2 ± 10.5 y, BMI 32.2 ± 8.0 kg/m2) and controls (65% female, age 44.5 ± 14.6 y, BMI 30.8 ± 6.3 kg/m2). 87% of PBH reported level 3 hypoglycemia, with emergency visits in 28% and vehicle accidents in 8%. Reduced hypoglycemia awareness was reported by 82%; 13%-17% were classified as unaware (modified Clarke/Gold scores). Preoperative hypoglycemia symptoms and family history were reported by 26% and 18% of PBH. PBH had significantly higher survey scores for hypoglycemia, dumping syndrome, and autonomic symptoms, and higher self-reported neuropathy, autonomic neuropathy, orthostatic hypotension, reflux esophagitis, intestinal dysmotility, and IBS (all p < 0.05 vs. RYGB non-hypo). Gabapentin and PPI use was more frequent in PBH.

CONCLUSION

High rates of IBS, dumping symptoms, and orthostatic hypotension suggest disordered autonomic regulation as a potential contributor to PBH. Self-reported preoperative symptoms and family history of hypoglycemia suggest possible preoperative differences in glucose metabolism in PBH.

Dasiglucagon Treatment for Postprandial Hypoglycemia After Gastric Bypass: A Randomized, Double-Blind, Placebo-Controlled Trial

OBJECTIVE

Postbariatric hypoglycemia affects >50% of individuals who have undergone Roux-en-Y gastric bypass surgery. Despite the often debilitating nature of this complication, existing treatment options are limited and often inefficient. Dasiglucagon is a stable glucagon analog available in a ready-to-use formulation and was recently shown to mitigate postbariatric hypoglycemia in experimental settings. Here, we aimed to evaluate the hypoglycemic hindering potential of dasiglucagon in an outpatient trial.

RESEARCH DESIGN AND METHODS

We conducted a randomized, double-blind, placebo-controlled, crossover, proof-of-concept study at the Center for Clinical Metabolic Research at Gentofte Hospital in Denmark. The study included 24 individuals who had undergone Roux-en-Y gastric bypass surgery (n = 23 women) with continuous glucose monitor-verified postbariatric hypoglycemia (≥15 min at <3.9 mmol/L three or more times per week) randomly assigned to two treatment periods of 4 weeks of self-administered subcutaneous dasiglucagon at 120 μg or placebo. The primary and key secondary outcomes were continuous glucose monitor-captured percentage of time in level 1 and 2 hypoglycemia (<3.9 and <3.0 mmol/L), respectively.

RESULTS

Compared with placebo, treatment with dasiglucagon significantly reduced time in level 1 hypoglycemia by 33% (-1.2 percentage points; 95% CI -2.0 to -0.5; P = 0.002) and time in level 2 hypoglycemia by 54% (-0.4 percentage points; 95% CI -0.6 to -0.2; P < 0.0001). Furthermore, dasiglucagon corrected hypoglycemia within 15 min in 401 of 412 self-administrations, compared with 104 of 357 placebo self-administrations (97.3% vs. 29.1% correction of hypoglycemia rate; P < 0.001). Dasiglucagon was generally well tolerated, with mostly mild to moderate adverse events of nausea.

CONCLUSIONS

Compared with placebo, 4 weeks of self-administered dasiglucagon effectively reduced clinically relevant hypoglycemia in individuals who had undergone Roux-en-Y gastric bypass surgery.

Medical Nutrition Therapy and Other Approaches to Management of Post-bariatric Hypoglycemia: A Team-Based Approach

PURPOSE OF REVIEW

This manuscript provides a review of post-bariatric hypoglycemia (PBH) with a special focus on the role of the registered dietitian-nutritionist (RDN) and medical nutrition therapy (MNT) recommendations as foundational for management.

RECENT FINDINGS

As the number of bariatric surgeries rises yearly, with 256,000 performed in 2019, PBH is an increasingly encountered late complication. Following Roux-en-Y (RYGB) or vertical sleeve gastrectomy (VSG), about 1/3 of patients report symptoms suggestive of at least mild postprandial hypoglycemia, with severe and/or medically confirmed hypoglycemia in 1-10%. Anatomical alterations, changes in GLP1 and other intestinally derived hormones, excessive insulin response, reduced insulin clearance, impaired counterregulatory hormone response to hypoglycemia, and other factors contribute to PBH. MNT is the cornerstone of multidisciplinary treatment, with utilization of personal continuous glucose monitoring to improve safety when possible. While many individuals require pharmacotherapy, there are no currently approved medications for PBH. Increasing awareness and identification of individuals at risk for or with PBH is critical given the potential impact on safety, nutrition, and quality of life. A team-based approach involving the individual, the RDN, and other clinicians is essential in providing ongoing assessment and individualization of MNT in the long-term management of PBH.