Clinical Value of HbA1c/ updated GMI Ratio in Identifying Early Retinopathy Risk in Type 1 Diabetes

Abstract

Background:

Discrepancies between HbA1c and glucose management indicator (GMI) may reflect individual variations in glycation rate, independent of mean glycemia, and could influence complication risk stratification in type 1 diabetes (T1D). We evaluated the phenotype of individuals with T1D using continuous glucose monitoring (CGM), identified as high glycators based on HbA1c/_updatedGMI ratio, and assessed retrospectively their risk of diabetic retinopathy (DR) and the time to DR diagnosis. The secondary aim was to identify clinical correlates of high glycation. Primary outcome: time to first diagnosis of DR. Secondary outcomes: clinical factors associated with high glycation.

Methods:

A retrospective study of 411 individuals with T1D using CGM and concurrent HbA1c values. Patients with conditions affecting red blood cell (RBC) lifespan were excluded. Participants were divided into 3 subgroups based on current HbA1c/_updatedGMI ratio ≤0.95 (low glycators), >0.95 and <1.05 (concordant glycators), and ≥1.05 (high glycators). Time to diagnosis of DR was retrieved.

Results:

High glycation is associated with shorter time to first diagnosis of DR (adjusted hazard ratio 1.60). Non-HDL-C, RBC indices, and metformin were associated with high glycation.

Conclusion:

Among individuals with T1D, an HbA1c/_updatedGMI ratio ≥1.05 is associated with higher odds of DR. Non-HDL-C and RBC indices are correlates of high glycation. These results underscore the relevance of HbA1c and _updatedGMI discrepancy in cardiometabolic risk assessment, but cutoffs remain to be set.