Prevalence and pathophysiology of early dumping in patients after primary Roux-en-Y gastric bypass during a mixed-meal tolerance test

Dumping Syndrome: Pragmatic Treatment Options and Experimental Approaches for Improving Clinical Outcomes

Dumping syndrome is a common complication after esophageal, gastric and bariatric surgery and has a significant negative impact on the quality of life of patients. This narrative review describes the clinical syndrome, pathophysiology, diagnosis and reports on standard and pragmatic therapeutical treatment options in order to improve the clinical outcome of patients with dumping syndrome. Dumping syndrome consists of early and late dumping symptoms and can be diagnosed using clinical parameters with the help of the Sigstad's score, questionnaires or by provocative testing. The prevalence of dumping syndrome varies depending on the employed definition of dumping syndrome. Overall, dumping syndrome is more frequent nowadays due to increasing numbers of upper gastrointestinal and bariatric surgeries being performed. First treatment step includes dietary adjustment and dietary supplements, which are often sufficient to manage symptoms for the majority of patients. Next step of therapy includes acarbose, which is effective for late dumping symptoms, but the use is limited due to side effects. Somatostatin analogues are indicated after these two steps have failed. Somatostatin analogues are very effective for controlling early and late dumping, also in the long term. Glucagon like peptide-1 receptor agonists, endoscopic and surgical (re)interventions are reported as treatment options for refractory dumping syndrome; however, their use is not recommended in clinical practice due to the limited evidence on and uncertainty of outcomes. These alternatives should be considered only as last resort options in patients with otherwise refractory and invalidating dumping syndrome.

Prevalence of Dumping Syndrome and Its Determinants Among Post-Bariatric Surgery Adult Patients at King Fahad General Hospital, Jeddah, 2019-2020

Background Bariatric surgery is one of the most effective interventions for morbid obesity. Despite its benefits, unwanted consequences such as dumping syndrome (DS) have been reported following the procedure. This study aims to estimate the prevalence of DS and identify the factors associated with it in Saudi Arabia. Methodology This cross-sectional study collected data from patients who underwent bariatric surgery at King Fahad General Hospital, Jeddah, Saudi Arabia, in 2019-2020. A validated questionnaire was used to collect the data. The questionnaire included demographic items such as age and sex and items relating to DS such as nausea, vomiting, and palpitations. A modified version of the Sigstad diagnostic scoring system was used to confirm the diagnosis. Results Of the 240 investigated cases, two-thirds (67.5%) were females. The most reported symptoms were nausea (37.9%), vomiting (36.7%), desire to lie down (25.5%), restlessness (25.5%), and abdominal fullness (23.7%). Based on the modified Sigstad diagnostic scoring system, 75 (31.4%) patients met the criteria for DS. The bivariate analysis showed the prevalence was significantly higher in females (36.4%), those with university qualifications (40.3%), and those with high monthly income (62.5%) (p<0.05). Also, dietary behaviors in terms of frequency, size of meals, and drinking liquids with meals were significantly associated with the prevalence of DS, where the lowest prevalence was recorded among those who ate more than one small meal (10.9%), while the highest prevalence was found in those who ate more than one large meal (81.8%); also, the prevalence was significantly higher in patients who drank liquids with meals (40.8%) than those who drank liquids between meals (26.8%) (p<0.05). Conclusion In this single institutional study, we report a 31.4% prevalence of DS among our cohort. The predictors of the syndrome include gender, education level, monthly income, eating more than one large meal per day, and drinking liquids with meals. In the future, these predictors will be explained to patients before and after bariatric surgery to reduce the prevalence of such inconvenient syndromes.

Obesity Surgery

BACKGROUND

In 2017, the prevalence of obesity (BMI ≥= 30 kg/m2) in Germany was approximately 16%. Obesity increases an individual's risk of developing type 2 diabetes (T2DM) and arterial hypertension; it also increases overall mortality. Consequently, effective treatment is a necessity. Approximately 20 000 bariatric operations are performed in Germany each year.

METHODS

This review is based on pertinent publications retrieved by a selective search in the PubMed and Cochrane databases and on current German clinical practice guidelines.

RESULTS

The types of obesity surgery most commonly performed in Germany, Roux-en-Y gastric bypass and sleeve gastrectomy, lead to an excess weight loss of 27-69% ≥= 10 years after the procedure. In obese patients with T2DM, the diabetes remission rate ≥= 10 years after these procedures ranges from 25% to 62%. Adjusted regression analyses of data from large registries have shown that the incidence of malignancies is 33% lower in persons who have undergone obesity surgery compared to control subjects with obesity (unadjusted incidence 5.6 versus 9.0 cases per 1000 person-years). The operation can cause vitamin deficiency, surgical complications, gastroesophageal reflux, and dumping syndrome. Therefore, lifelong follow-up is necessary.

CONCLUSION

In view of an increasing number of patients undergoing bariatric surgery, it will probably not be feasible in the future for lifelong follow-up to be provided exclusively in specialized centers.

Dumping Syndrome and Postbariatric Hypoglycemia: Supporting Evidence for a Common Etiology

BACKGROUND

Dumping syndrome (DS) and postbariatric hypoglycemia (PBH) are frequent complications of bariatric surgery. Previously known as "early and late dumping," these complications have been separated due to differences in their onset and behaviors.

OBJECTIVES

To investigate a potentially common etiology of DS and PBH using an analysis of a mixed meal test (MMT) study.

SETTING

A large teaching hospital in the Netherlands.

METHODS

From all patients who underwent bariatric surgery in 2008-2011, a random selection completed an MMT (n = 47). Patients scored complaints related to DS and PBH with a standardized questionnaire at several time intervals. The groups were divided into patients with (DS+; n = 22) and without (DS-; n = 25) an increase in DS symptoms after the start of the MMT. Glucose and gut hormone levels were compared. Hypoglycemia was defined as a blood glucose level below 3.3 mmol/L.

RESULTS

The DS+ group had lower blood glucose values compared to the DS- group, which reached significance at 90 and 120 minutes (P < .05). For the DS+ group, glucagon-like peptide-1 (GLP-1), peptide YY (PYY), and satiety were higher at various time intervals (P < .05) compared to the DS- group. No differences were found for insulin and hunger score. GLP-1 and PYY were correlated with symptoms of DS.

CONCLUSION

Patients with DS complaints had lower postprandial glucose values. GLP-1 and PYY values were elevated in the DS+ group early and late during the test. These hormones also correlated with DS. These findings support the hypothesis of a common etiology of DS and PBH and a role of GLP-1 and PYY in both complications.

Altered bile acid kinetics contribute to postprandial hypoglycaemia after Roux-en-Y gastric bypass surgery

BACKGROUND/OBJECTIVES

Bile acids (BA) act as detergents in intestinal fat absorption and as modulators of metabolic processes via activation of receptors such as FXR and TGR5. Elevated plasma BA as well as increased intestinal BA signalling to promote GLP-1 release have been implicated in beneficial health effects of Roux-en-Y gastric bypass surgery (RYGB). Whether BA also contribute to the postprandial hypoglycaemia that is frequently observed post-RYGB is unknown.

METHODS

Plasma BA, fibroblast growth factor 19 (FGF19), 7α-hydroxy-4-cholesten-3-one (C4), GLP-1, insulin and glucose levels were determined during 3.5 h mixed-meal tolerance tests (MMTT) in subjects after RYGB, either with (RYGB, n = 11) or without a functioning gallbladder due to cholecystectomy (RYGB-CC, n = 11). Basal values were compared to those of age, BMI and sex-matched obese controls without RYGB (n = 22).

RESULTS

Fasting BA as well as FGF19 levels were elevated in RYGB and RYGB-CC subjects compared to non-bariatric controls, without significant differences between RYGB and RYGB-CC. Postprandial hypoglycaemia was observed in 8/11 RYGB-CC and only in 3/11 RYGB. Subjects who developed hypoglycaemia showed higher postprandial BA levels coinciding with augmented GLP-1 and insulin responses during the MMTT. The nadir of plasma glucose concentrations after meals showed a negative relationship with postprandial BA peaks. Plasma C4 was lower during MMTT in subjects experiencing hypoglycaemia, indicating lower hepatic BA synthesis. Computer simulations revealed that altered intestinal transit underlies the occurrence of exaggerated postprandial BA responses in hypoglycaemic subjects.

CONCLUSION

Altered BA kinetics upon ingestion of a meal, as frequently observed in RYGB-CC subjects, appear to contribute to postprandial hypoglycaemia by stimulating intestinal GLP-1 release.

The Prognostic Value of the Dutch Sweet Eating Questionnaire on Weight Loss After Metabolic Surgery: a Randomized Controlled Trial

BACKGROUND

Laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG) have shown different weight loss results. These differences might be partly due to dumping after LRYGB, forcing sweet eaters to switch to a healthy diet. The Dutch Sweet Eating Questionnaire (DSEQ) is validated to measure sweet eating. This study aims to investigate if sweet eating measured with the DSEQ influences weight loss.

METHODS

In this multicenter randomized controlled trial, patients were included between 2013 and 2017 in two Dutch high-volume hospitals, and randomized with a 1:1 ratio between LRYGB and LSG. Primary outcome measure was weight loss. Secondary outcome measure was sweet eating behavior, measured with the DSEQ. Data was collected at baseline, 1 year and 2 years postoperatively.

RESULTS

Data was analyzed of 623 patients who underwent LRYGB (n = 308; 49.4%) or LSG (n = 315; 50.6%). Follow-up rates at 2 years postoperative were 67.1% for weight and 35.3% for DSEQ. At 2 years postoperative, mean BMI was significantly higher after LSG than LRYGB (respectively 30.88 versus 28.87 kg/m², p < 0.001), and the percentage of sweet eaters was significantly higher after LSG than LRYGB (respectively 8.6% versus 2.6%, p = 0.049). None of the preoperative sweet eaters were sweet eaters 2 years after LRYGB (0.0%), versus 11.8% 2 years after LSG. No correlation was found between postoperative sweet eating behavior and %EBMIL.

CONCLUSION

No significant correlation was found between preoperative or postoperative sweet eating measured with the DSEQ and weight loss. The decision-making for the procedure type is more complex than weight loss and dietary habits, and should also involve quality of life and presence of comorbidities. These factors should be addressed in future research along with longer term results.

TRIAL REGISTRATION

Dutch Trial Register NTR-4741.

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.