Metabolic Consequences of Restorative Surgery After Gastric Bypass

Diagnosis and management of post-bariatric surgery hypoglycemia

INTRODUCTION

While bariatric surgery remains the most effective treatment for obesity that allows substantial weight loss with improvement and possibly remission of obesity-associated comorbidities, some postoperative complications may occur. Managing physicians need to be familiar with the common problems to ensure timely and effective management. Of these complications, postoperative hypoglycemia is an increasingly recognized complication of bariatric surgery that remains underreported and underdiagnosed.

AREA COVERED

This article highlights the importance of identifying hypoglycemia in patients with a history of bariatric surgery, reviews pathophysiology and addresses available nutritional, pharmacological and surgical management options. Systemic evaluation including careful history taking, confirmation of hypoglycemia and biochemical assessment is essential to establish accurate diagnosis. Understanding the weight-dependent and weight-independent mechanisms of improved postoperative glycemic control can provide better insight into the causes of the exaggerated responses that lead to postoperative hypoglycemia.

EXPERT OPINION

Management of post-operative hypoglycemia can be challenging and requires a multidisciplinary approach. While dietary modification is the mainstay of treatment for most patients, some patients may benefit from pharmacotherapy (e.g. GLP-1 receptor antagonist); Surgery (e.g. reversal of gastric bypass) is reserved for unresponsive severe cases. Additional research is needed to understand the underlying pathophysiology with a primary aim in optimizing diagnostics and treatment options.

Effect of Gastrogastric Fistula Closure in Type 2 Diabetes

INTRODUCTION

Roux-en-Y gastric bypass (RYGB) has been shown to significantly improve glucose control in patients with type 2 diabetes (T2DM). The formation of a gastrogastric fistula (GGF) allows nutrients to pass through the native route, rather than bypassing the duodenum in typical RYGB configuration. We sought to evaluate the effect of revisional bariatric surgery for known GGF on control of diabetes.

METHODS

A retrospective chart review of a single academic institution was performed to identify patients who had T2DM at the time of corrective surgery for a GGF. Baseline characteristics, and postoperative outcomes including changes in body mass index (BMI), glycated hemoglobin, fasting blood glucose (FBG), and diabetes medications were assessed.

RESULTS

Ten patients were identified with GGF who had T2DM at the time of corrective surgery. Patients had a male-to-female ratio of 2:3, a mean age of 59.2 ± 10 years, a mean baseline BMI of 38.1 ± 17.6 kg/m², and a median duration of 9 years (interquartile range 6-14) from initial RYGB to revision. At a mean follow-up of 14.9 ± 8.5 months, a mean reduction in BMI of 4.9 ± 6 kg/m² was associated with a significant mean reduction in FBG (167.1 ± 88.2 vs. 106.1 ± 20.4 mg/dL, p = 0.04) and number of diabetes medications (1.4 ± 0.8 vs. 0.7 ± 0.7, p = 0.04).

CONCLUSION

In patients with diabetes and GGF, a corrective surgery for closure of fistula and restoration of bypass anatomy results in improvement of glucose control and status of diabetes medications. This finding can highlight the potential metabolic significance of duodenal exclusion.