The A1C-Derived Average Glucose (ADAG) Study

OBJECTIVE—Various methods are used to quantify postpran-dial glycemia or glucose variability, but few have been compared and none are standardized. Our objective was to examine the relationship among common indexes of postprandial glycemia, overall hyperglycemia, glucose variability, and A1C using de-tailed glucose measures obtained during everyday life and to study which blood glucose values of the day provide the stron-gest prediction of A1C. RESEARCH DESIGN AND METHODS—In the A1C-Derived Average Glucose (ADAG) study, glucose levels were monitored in 507 participants (268 type 1 diabetic, 159 type 2 diabetic, and 80 nondiabetic subjects) with continuous glucose monitoring (CGM) and frequent self-monitoring of blood glucose (SMBG) during 16 weeks. We calculated several indexes of glycemia and analyzed their intercorrelations. The association between glu