Circulating levels of endothelial progenitor cells (EPCs) involved in endothelial homeostasis are often reduced in people with type 1 diabetes (T1D). The Glycemia Risk Index (GRI) quantifies the quality of glucose control by assessing both hypo- and hyperglycemia risk. We aim to investigate the association between the GRI and circulating EPC levels in people with T1D. This cross-sectional study included 132 adults with T1D, on intensive insulin therapy. We calculated GRI from 14 days continuous glucose monitoring-derived metrics and quantified EPCs count by flow cytometry, stratifying results by GRI zones, ranging from A (lowest risk) to E (highest risk). Higher GRI scores were significantly associated with poorer metabolic parameters. Circulating levels of CD34⁺, CD133⁺, KDR⁺, and CD34⁺KDR⁺ cells were lower in participants with a worse GRI compared to adults with a better GRI. Linear regression analyses showed a negative association between GRI and CD34⁺ (β = −1.079, p = 0.006), CD34⁺CD133⁺ (β = −0.581, p = 0.008), and CD34⁺KDR⁺ (β = −0.147, p = 0.010). No significant association was found between HbA_1c and any EPC phenotype. Adults with T1D and a high GRI level had a lower EPCs count. GRI was significantly associated with certain EPC phenotypes, suggesting its potential role as a biomarker for cardiovascular risk assessment.

Aims: To investigate the independent association between long-term glycemic variability, measured as the coefficient of variation (CV) of HbA1c, and the presence of diabetic retinopathy (DR) in a cohort of adults with diabetes within a systematic eye screening program. Methods: This study screened 379 adults with type 1 and type 2 diabetes. Long-term glycemic variability was calculated as the CV of serial HbA _1c measurements. DR was assessed via dilated fundus photography. The association between HbA _1c CV and DR was analyzed using multivariable logistic regression adjusting for confounders. Results: DR incidence of 12.4%, mostly mild non-proliferative. The median HbA _1c CV was 7.0% (53 mmol/mol). In unadjusted bivariate analysis, the incidence of mild DR was higher in the low- glycemic variability group (CV < 5%) compared to the high- glycemic variability group. However, the multivariable logistic regression analysis revealed that higher HbA _1c CV was independently associated with the presence of DR (β = 0.643, P = 0.042), alongside diabetes duration (P < 0.001) and age (P < 0.001). Conclusions: In conclusion, in a cohort of individuals with both type 1 and type 2 diabetes and a low incidence of DR, long-term glycemic variability, estimated as HbA _1c CV, was independently associated with an increased risk of this complication.