Time above range and no coefficient of variation is associated with diabetic retinopathy in individuals with type 1 diabetes and glycated hemoglobin within target

Aims: This study aimed to investigate the association between glucose metrics and diabetic retinopathy in type 1 diabetes (T1D) patients using flash continuous glucose monitoring (FGM) systems, including those maintaining glycated hemoglobin (HbA1c) within the target range. Methods: We conducted a cross-sectional study involving 1070 T1D patients utilizing FGM systems. Data on clinical, anthropometric, and socioeconomic characteristics were collected and retinopathy was classified based on international standards. Results: Patients’ mean age was 47.6 ± 15.0 years, with 49.4% of them being females. Within the cohort, 24.8% of patients presented some form of retinopathy. In the analysis involving the entire sample of subjects, male gender (OR = 1.51, p = 0.027), Time Above Range (TAR) > 250 mg/dL (OR = 1.07, p = 0.025), duration of diabetes (OR = 1.09, p < 0.001), smoking (OR = 2.30, p < 0.001), and history of ischemic stroke (OR = 5.59, p = 0.025) were associated with diabetic retinopathy. No association was observed between the coefficient of variation and diabetic retinopathy (p = 0.934). In patients with HbA1c < 7%, the highest quartile of TAR > 250 was independently linked to diabetic retinopathy (OR = 8.32, p = 0.040), in addition to smoking (OR = 2.90, p = 0.031), duration of diabetes (OR = 1.09, p < 0.001), and hypertension (OR = 2.35, p = 0.040). Conclusion: TAR > 250 mg/dL significantly emerges as a modifiable factor associated with diabetic retinopathy, even among those patients maintaining recommended HbA1c levels. Understanding glucose metrics is crucial for tailoring treatment strategies for T1D patients.