Background: Past analyses have shown significant discordance between glycated hemoglobin (A1C) and glucose management indicator (GMI). This study uses a glycation ratio (GR) defined as GMI/A1C and evaluates the association of this ratio with microvascular complications in 661 patients with diabetes.

Methods: A retrospective review was done of patients with diabetes using CGM who were seen at the University of Washington (UW) Diabetes Care Center from 2012-2019. All patients had A1C and sensor data obtained fewer than 4 weeks apart. Positive discordance was defined as GMI/A1c <0.9.

Results: This study included 661 patients of whom 90% had type 1 diabetes with a mean duration of current CGM use of 24.7 days (+/- 7.9 days). Positive discordance was found in 29.9% of participants and was associated with retinopathy (OR 2.05, CI 1.33-3.14) and nephropathy (OR 2.83, CI 1.68-4.77). The data were modeled as a continuous nonlinear function revealing an inverse relationship between GMI/A1C and diabetic retinopathy.

Discussion: In this study positive discordance conferred a more than two-fold increased risk for diabetic retinopathy and nephropathy. Modeling of GMI/A1C as a continuous variable upheld this relationship for diabetic retinopathy. These data suggest that GMI/A1C ratios may allow for identification of patients at increased risk for microvascular complications.


L.Bovee: None. J.Perlman: None. T.Gooley: None. I.B.Hirsch: Consultant; Abbott Diabetes, Lifecare, Inc., Hagar, Research Support; Beta Bionics, Inc., Insulet Corporation, Dexcom, Inc.

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