The Role of a Continuous Glucose Monitoring-Derived Glycation Ratio in the Development of Microvascular Complications

Background: Previous studies have evaluated the associations between HbA1c discordance and diabetes complications using indices of glycation. The ideal index would allow for identification of those at increased risk for microvascular complications. This analysis evaluates the association of a newly published index, the glycation ratio (GR), with diabetic retinopathy (DR) and diabetic kidney disease (DKD). Methods: This is a retrospective review of 661 patients with diabetes seen at the University of Washington. All patients used continuous glucose monitoring (CGM) before the study. Diabetes duration was greater than 20 years in 59%. Median age was 45 years. GR was defined as the ratio of the glucose management indicator (GMI) to the HbA1c. The associations of GR with microvascular complications were each assessed using logistic regression. Results: Modeling GR as a continuous linear variable, each increase in GR of 0.20 units was associated with a 38% relative reduction in the odds of DR (adjusted odds ratio [OR] = 0.62; 95% confidence interval [CI]: 0.45-0.86, P = 0.004] and a similar reduction in the odds of DKD (OR = 0.61; 95% CI: 0.41-0.93, P = 0.02). Conclusions: GR may be a useful marker for risk of diabetic microvascular complications. Longitudinal assessment will be required to see how well GR compares with GMI or HbA1c alone.