Comparison between RYGB, DS, and VSG effect on glucose homeostasis

Obes Surg. 2012 Aug;22(8):1281-6. doi: 10.1007/s11695-012-0686-0.


Background: Our group has reported a high incidence of reactive hypoglycemia following Roux-en-Y gastric bypass (RYGB) with specific interest in postprandial insulin and the ratio of 1- to 2-h serum glucose levels. The purpose of this study is to compare the 6-month response to oral glucose challenge in patients undergoing RYGB, duodenal switch (DS), and vertical sleeve gastrectomy (VSG).

Methods: Thirty-eight patients meeting the NIH criteria for bariatric surgery who have reached the 6-month postoperative mark are the basis of this report. Preoperatively and at 6 months follow-up, patients underwent blood draw to determine levels of fasting glucose, fasting insulin, HbA1c, C peptide, and 2 h oral liquid glucose challenge test (OGTT). HOMA-IR and 1 to 2 h ratios of glucose and fasting to 1 h ratio of insulin were calculated.

Results: All patients underwent a successful laparoscopic bariatric procedure (VSG =13, DS =13, and RYGB = 12). All operations reduced BMI, HgbA1c, fasting glucose, and fasting insulin. HOMA IR and glucose tolerance improved with all procedures. In response to OGTT at 6 months, there was a 20-fold increase in insulin at 1 h in RYGB, which was not seen in DS. At 6 months, 1-h insulin was markedly lower in DS (p < .05), yet HbA1C was also lower in DS (p < .05). This resulted in 1- to 2-h glucose ratio of 1.9 for RYGB, 1.8 for VSG, and 1.3 for DS (p < .05).

Conclusions: All operations improve insulin sensitivity and decrease HgbA1c. Six-month weight loss was substantial in all groups between 22-29% excess body weight. RYGB results in marked rise in glucose following challenge with corresponding rise in 1-h insulin. VSG has a similar response to RYGB. In comparison, at 6 months following surgery, DS causes a much lower rise in 1-h insulin, with this difference being statistically significant at p < .05. As a result, DS results in a less abrupt reduction in blood glucose. Although 1-h insulin is lower, DS patients had the lowest HbA1C at 6 months (p < .05). We believe that these findings have important implications for the choice of bariatric procedure for both diabetic and non-diabetic patients.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Blood Glucose / metabolism*
  • Body Mass Index
  • C-Peptide / blood
  • Duodenum / surgery*
  • Female
  • Follow-Up Studies
  • Gastric Bypass* / adverse effects
  • Gastric Bypass* / methods
  • Gastroplasty* / methods
  • Glucose Tolerance Test
  • Glycated Hemoglobin A / metabolism
  • Homeostasis
  • Humans
  • Hypoglycemia / blood
  • Hypoglycemia / physiopathology
  • Hypoglycemia / surgery*
  • Insulin Resistance
  • Male
  • Obesity, Morbid / blood
  • Obesity, Morbid / physiopathology
  • Obesity, Morbid / surgery*
  • Prospective Studies
  • Treatment Outcome
  • Weight Loss


  • Blood Glucose
  • C-Peptide
  • Glycated Hemoglobin A
  • hemoglobin A1c protein, human