Resolution of type 2 diabetes after sleeve gastrectomy: a 2-step hypothesis.

BACKGROUND

Weight loss (WL) and altered gut hormonal levels are involved in glucose homeostasis after laparoscopic sleeve gastrectomy (LSG).

OBJECTIVES

The aim of this study was to evaluate the time-related effects of WL, ghrelin, and glucacon-like peptide-1 (GLP-1) plasma concentrations on type 2 diabetes resolution after LSG.

SETTING

University hospital, Italy.

METHODS

Ninety-one patients who underwent LSG were investigated. Insulin secretion (insulinogenic index [IGI]), insulin resistance, plasma glucose level and percentage glycated hemoglobin using the oral glucose tolerance test were assessed before surgery, on postoperative day 3, and then at 6, 12, 24, and 36 months after LSG. At the same time points, WL, ghrelin, and GLP-1 levels were determined.

RESULTS

During follow-up, the resolution rate of type 2 diabetes was 9.4%, 42.3%, 71.8%, 81.2%, and 91.8%, respectively. Ghrelin plasma concentrations decreased significantly after LSG (271.5 ± 24.5 pg/mL versus 122.4 ± 23.4 pg/mL, P = .04). GLP-1 plasma concentrations increased significantly after LSG (1.7 ± 2.6 pg/mL versus 2.5 ± 3.4 pg/mL, P = .04). The percentage of excess weight loss and IGI presented a positive linear correlation (r) at all follow-up time points with a strong positive correlation at 12 and 24 months. A strong negative correlation between ghrelin and IGI was recorded during the first 3 days after LSG (r = -.9). GLP-1 and IGI presented a strong positive correlation at day 3 and 6 months (i.e., .8 and .8, respectively).

CONCLUSION

LSG may affect glucose homeostasis by 2 different time-related modes: a first step in which the hormonal changes play a predominant role in glucose homeostasis and a second step in which the percentage excess weight loss determines the metabolic results.