Introduction: Bariatric surgery has been proved to be the most effective treatment for type 2 diabetes mellitus (T2D). Post-operative improvement in insulin sensitivity seems to be partly independent of weight loss and may be affected by changes in incretin secretion. Previous studies reported that the glucose-dependent insulinotropic polypeptide (GIP)-induced enhancement of fat stores may lead to increased insulin resistance. We determinated the effect of laparoscopic adjustable gastric banding (LAGB) and biliopancreatic diversion (BPD) on glucose profile and on secretion of GIP in response to meal test.
Methods: Our cohort included 23 obese T2D women who underwent bariatric surgery: 11 BPD (age:50±6.2y; BMI:47±7.8), 12 LAGB (age:54±9.5y; BMI:44±7.3). Meal test (300 ml protein drink) and euglycaemic hyperinsulinaemic clamp were performed before, 1 month after surgery and at time when 15% weight loss was achieved. Investigated parameters: BMI, insulin resistance/sensitivity, and GIP. Statistical analysis: ANOVA with repeated measures.
Results: We confirmed that BPD had more significant impact on weight loss than LAGB (P=0.0002). Both surgeries significantly reduced HbA1c (P=0.001), but in the long-term perspective, BPD seems to be more efficient with regard to HbA1c reduction (P=0.06). In response to surgery insulin resistance measured by HOMA-IR significantly decreased (P=0.0001) while insulin sensitivity measured by clamp increased (P=0.0002) but there was no interaction with the type of surgery. No difference in fasting levels of GIP between the study groups was observed. On the other hand, stimulated levels of GIP after the meal test were significantly reduced in BPD group in comparison with LAGB group (P=0.003).
Conclusion: Both BPD and LAGB positively affected insulin sensitivity. However, a better glucose control was observed with 15% body weight reduction after BPD. Decreased GIP levels revealed during the meal test may contribute to the positive changes in glucose metabolism in patients who underwent BPD.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This work was supported, however funding details unavailable.
05 - 09 May 2012
European Society of Endocrinology