SUSTAINED CHANGES IN GLP-1 AND INSULIN 12 MONTHS AFTER LAPAROSCOPIC GASTRIC BANDING SURGERY

Bariatric surgery has been effective in promoting sustained weight loss and improving diabetes control in many patients with morbid obesity. Increases in GLP-1 after bariatric surgery have been implicated in improved glucose homeostasis in studies examining Roux-en-Y gastric bypass. However similar studies in laparoscopic gastric banding surgery (LGBS) have been conflicting. The co-authors of the present study previously reported an increase in GLP-1 and a decrease in insulin 6 months after LGBS. The aim of this study was to further evaluate sustained changes in GLP-1 and insulin after LGBS. Purpose (a): The following hypotheses were examined: (1) Fasting and post-prandial (pp) GLP-1 will be increased 12 months after LGBS, and (2) Fasting and pp-insulin will be decreased after LGBS. Relationships between GLP-1 and weight loss were explored. Methods (b): Thirteen LGBS patients (9 women and 4 men) who underwent pre-surgical and 6-month post-surgical testing were retested at 12-months post-surgically. Average baseline BMI was 40.5 (32.4-48.4). Average age was 47.5 (24-66). Fasting and pp-blood samples were taken to evaluate GLP-1 and insulin. Data were analyzed using repeated measures ANOVA. Results (c): In comparison to baseline, fasting GLP-1 increased (F=6.46, p=0.006), fasting insulin decreased (F=6.11, p=0.022) and pp-insulin decreased (F=9.46, p=0.008). The ppGLP-1 increase approached significance (F=3.70, p=0.065), with a significant post-hoc pairwise finding at 12-months in comparison to baseline (p=0.004). Conclusions (d): Results suggest that LGBS improves GLP-1 and insulin as early as 6 months and that these improvements persist up to 1 year. Overall, these improvements appear independent of weight loss, although exploration of data suggests a possible connection with post-prandial GLP-1 at 12-months. These results provide further evidence of the efficacy of LGBS for the treatment of diabetes.