Glycemic Variability from CGM Correlates with Indices of Glucose Metabolism in Healthy Obesity but Not in Type 2 Diabetes

We evaluated the relationship between measurements of beta cell function and insulin resistance assessed from OGTT and 2-step glucose clamp data with indices of glucose variability (GV) obtained with a continuous glucose monitor (CGM) in obese subjects with and without type 2 diabetes (T2D). 17 healthy obese (OB) (FPG 91 ± 4.9mg/dl and A1c 5.2 ± 0.4%) and 8 age- and weight-matched participants with T2D treated with diet and/or metformin (FPG 131.5 ± 42.8 mg/dl and A1c 6.8 ± 0.8%) wore CGM (Dexcom ® ) for up to 5 days. EasyGV ® software was used to calculate indices of GV: standard deviation (SD), mean amplitude of glycemic excursions (MAGE), J-Index, continuous overlapping net glycemic action (CONGA), and Glycemic Risk Assessment in Diabetes Equation (GRADE). Indices of glucose metabolism were determined with a 2 hour OGTT and a two-step hyperglycemic-euglycemic clamp. Insulin levels during the hyperglycemic-step of clamp (116 ± 126 vs. 40 ± 23 mU/mL) were equal in both groups, while glucose infusion rate (GIR) (7.7 ± 3.1 vs. 3.9 ± 2.4 mg/kg/minutes) during euglycemia was as expected significantly lower in the T2D subjects compared to OB subjects. GV indices (SD, CONGA, J-Index, GRADE) were statistically lower in OB vs. T2D (P 0-120 ) and the insulin secretion-sensitivity index-2 (ISSI-2) were also lower in obese than in T2D subjects (P Disclosure A. Elshafie: None. W. Lam: None. L. Parikh: None. E. Sanchez Rangel: None. C.P. Schmidt: None. J. Hwang: None. C.W. Yeckel: None. R. Sherwin: Other Relationship; Self; QuintilesIMS, MannKind Corporation. Research Support; Self; Regeneron Pharmaceuticals, Inc.. Other Relationship; Self; ICON plc. R. Belfort-DeAguiar: Research Support; Self; GlaxoSmithKline plc..