Background

The purpose of this study is to investigate sequential changes in glucose metrics after metabolic-bariatric surgery and differences according to surgical procedure using a CGM system in individuals with T2DM and obesity. This retrospective study included 26 individuals with T2DM and obesity who underwent sleeve gastrectomy (SG), RYGB, and SG with loop duodenal-jejunal bypass. Intermittent scanned CGM system was applied to each participant before, immediately after and 3 months after metabolic-bariatric surgery. Mean glucose and %time above range (>250 or 180 mg/dL) decreased immediately after surgery (159.8 +- 35.7, 111.0 +- 14.6, and 108.4 +- 22.7mg/dL, P<0.001; 24.0 +- 15.7, 2.4 +- 3.9, and 4.1 +- 5.4, P<0.001, respectively), and %time in range (%TIR; 70 to 180 mg/dL) increased after surgery (67.4 +- 22.4, 96.4 +- 4.3, and 88.0 +- 15.8, P<0.001). However, %time below range (<70 or 54 mg/dL) and low glucose events significantly increased over time (1.3 +- 4.7, 1.0 +- 2.6, and 6.6 +- 13.8mg/dL, P=0.044; 0.4 +- 0.8, 0.9 +- 2.0, and 4.2 +- 6.1, P=0.001, respectively). In contrast, glucose coefficient of variation decreased sharply immediately after surgery and then returned to baseline level 3 months after surgery (25.2 +- 5.8, 19.2 +- 4.8, and 25.7 +- 8.1, P=0.001). When analyzing the differences in CGM metrics according to the type of surgery, there was no difference between sleeve gastrectomy and bypass surgery group. The CGM identified improvement of mean glucose and %TIR, distinct changes in glycemic variability over time, and increase of hypoglycemia after metabolic-bariatric surgery.