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The following is a summary of “Association between the GMI/HbA1c ratio and preclinical carotid atherosclerosis in type 1 diabetes: impact of the fast-glycator phenotype across age groups,” published in the February 2025 issue of the Cardiovascular Diabetology by Puig-Jove et al.

The introduction of continuous glucose monitoring (CGM) has significantly advanced the understanding of glycemic control in diabetes, particularly in the relationship between the glucose management indicator (GMI) and glycated hemoglobin (HbA1c). However, discrepancies between these two metrics have led to the identification of distinct glycation phenotypes, with potential implications for vascular complications. This study investigates the association between the GMI/HbA1c ratio and preclinical carotid atherosclerosis in individuals with type 1 diabetes (T1D), with a particular focus on the fast-glycator phenotype, characterized by a GMI/HbA1c ratio below 0.90. A multicenter cross-sectional analysis was conducted on individuals with T1D and no prior cardiovascular disease history. 

Carotid ultrasonography, performed using a standardized protocol, identified atherosclerotic plaques based on an intima-media thickness of ≥1.5 mm. CGM-derived data from a 14-day monitoring period were used to calculate GMI, and its relationship with laboratory-measured HbA1c was assessed. Of the 584 participants (319 women, 54.6%), the mean age was 48.8 ± 10.7 years, with a mean diabetes duration of 27.5 ± 11.4 years. Carotid plaques were detected in 231 individuals (39.6%). Notably, 43.7% of participants exhibited absolute GMI-HbA1c discrepancies of ≥0.5, while 13.4% showed differences of ≥1.0. Among individuals aged ≥48 years, the fast-glycator phenotype was independently associated with carotid plaque presence (odds ratio 2.27, 95% CI: 1.06–4.87), even after adjusting for general cardiovascular risk factors, T1D-specific variables, and statin use. However, no significant association was observed in younger individuals (p for interaction <0.05), suggesting an age-dependent impact of glycation on vascular risk. 

These findings underscore the potential clinical relevance of the GMI/HbA1c ratio in cardiovascular risk stratification for patients with T1D, particularly in older individuals. The identification of a fast-glycator phenotype may offer a novel biomarker for the early detection of atherosclerosis, informing tailored prevention and intervention strategies. Further longitudinal research is warranted to validate these associations and explore the mechanistic pathways linking glycation variability to vascular complications in T1D.

Source: cardiab.biomedcentral.com/articles/10.1186/s12933-025-02637-4