Impact of preoperative NAFLD status on restoration of pancreatic β-cell function after laparoscopic sleeve gastrectomy.

Although pancreatic beta-cell insufficiency is ameliorated after bariatric and metabolic surgery in subjects with obesity and type 2 diabetes (T2D), the mechanism and preoperative factors related to this amelioration have been uncertain. This study investigated the effect of laparoscopic sleeve gastrectomy (LSG) on beta-cell function. The preoperative characteristics and factors associated with the degree of postoperative changes in beta-cell function in those subjects were explored as well. In this subanalysis of our prospective observational study, subjects with obesity and T2D underwent oral glucose tolerance tests (OGTTs) and magnetic resonance imaging (MRI), at the baseline and the end of the 1-year follow-up period. Beta-cell function was evaluated by the insulin secretion-sensitivity index-2 (ISSI-2) and disposition index (DI), and the preoperative factors associated with these changes were examined. In 18 eligible subjects, glucose tolerance improved, ISSI-2 increased significantly, and DI also tended to increase 1 year after LSG. The change in ISSI-2 correlated with preoperative liver fibrosis assessed by MR elastography (r = -0.49, P < 0.05). In 16 subjects without severe fibrosis, changes in DI correlated with preoperative MRI-estimated proton density fat fraction (r = -0.52, P < 0.05). Neither as glycemic control nor visceral fat was significantly associated with the degree of amelioration in beta-cell function. Pancreatic beta-cell function improved at 1-year postoperative to LSG in subjects with obesity and T2D. Preoperative liver fibrosis and steatosis were associated with a lower degree of postoperative pancreatic beta-cell improvement.NEW & NOTEWORTHY In the present study, pancreatic beta-cell function improved at 1 year postoperatively in subjects with obesity and type 2 diabetes (T2D) who underwent laparoscopic sleeve gastrectomy. Preoperative liver fibrosis and steatosis were associated with a lower degree of postoperative pancreatic beta-cell improvement. Considering that amelioration of pancreatic beta-cell function leads to better outcome of T2D, the finding of this association would be clinically significant.