Prevalence of early dumping syndrome after primary Roux-en-Y gastric bypass

Background: Although early dumping syndrome is a well-known complication after Roux-en-Y Gastric Bypass (RYGB), data on the long-term prevalence are limited and inconclusive. This study aims to describe the prevalence of early dumping syndrome in patients 3 to 6 years after primary RYGB, using 3 different criteria. Methods: In this cross-sectional study a total of 140 patients after RYGB were randomly selected and approached. Of these, 51 patients agreed to participate in a Mixed-Meal Tolerance Test using a liquid nutrition supplement (Ensure Plus 200ml). The results of the first 28 are presented here. Heart Rate (HR) and Haematocrit (Ht) were measured at baseline and 10, 20, 30 and 60 minutes after the test meal. Symptoms scores were measured at baseline, 30 and 60 minutes. Early dumping was defined as a HR-increase of >10 beats per minute, a Ht-increase of >3%, and/or ≥2 gastrointestinal symptoms and ≥1 vegetative symptom on a symptom score. A confidence interval (CI) was calculated using the Clopper-Pearson method. Results: Prevalence of early dumping was 89% (n=25) according to HR (95% CI [0.72;0.98]); 32% (n=9) according to Ht (95% CI [0.16; 0.52]) and 7% (n=2) recorded symptom score (95% CI [0.01; 0.24]). In the vast majority the objective changes indicative of early dumping occurred within 10 minutes postprandially. Symptoms were reported within 30 minutes postprandially. Conclusions: The interim results show a large discrepancy of the prevalence of early dumping between the different criteria. Hemodynamic evidence of early dumping is only in a few cases accompanied by complaints.