Endocrine Abstracts

Introduction: Diabetic macular edema (DME) is one of the leading causes of visual impairment in individuals with diabetes. In type 1 diabetes (T1D), DME is often a late-stage complication of diabetic retinopathy (DR). However, literature remains scarce regarding risk factors for DME, particularly its relationship with glycemic control assessed by continuous glucose monitoring (CGM).

Methods: We conducted a retrospective cohort study of adult T1D patients using Freestyle Libre® CGM, who were followed at a tertiary diabetes and ophthalmology center between January 2022 and June 2024. Exclusion criteria included incomplete ophthalmological evaluations or <70% active CGM usage. Clinical and analytical variables were compared according to DME history. Logistic regression models adjusted for age and sex were performed to evaluate associations between CGM parameters and DME history.

Results: We included 110 patients, with 55% female, mean age of 45.8±12.7 years and T1D duration of 26.8±10.7 years. Sixty-two percent had DR. The average glycated hemoglobin (HbA1c) was 7.8±1.3%, and the mean time in range was 54.8±18.1%. Twenty-one percent had a history of DME, which developed after a mean T1D duration of 25.8±7.3 years. Among those with DME history, 52% exhibited proliferative DR. DME patients were older, had longer T1D duration, higher prevalence of other microvascular complications, systolic blood pressure and use of lipid-lowering and antihypertensive medications, along with lower estimated glomerular filtration rate (P < 0.001). No significant differences were found in HbA1c or CGM parameters according to DME status. Multivariable logistic regressions indicated a trend towards higher DME risk associated with increased glycemic variability, assessed by the coefficient of variation (OR=1.08, 95%CI 0.99-1.18; P = 0.068), and time below range (OR=1.76, 95%CI 0.92-3.40; P = 0.090).

Conclusion: In this cohort of T1D patients, those with history of DME exhibit a worse cardiometabolic profile. We also suggest that higher glycemic variability and time in hypoglycemia may elevate DME risk.