Increased Survival Reveals New Paradigms in Diabetic Macular Edema among Patients with Type 1 Diabetes

Abstract

Purpose: Treatment and monitoring developments improved the survival rate in type 1 diabetes (T1D). Nevertheless, literature remains scarce on long-term incidence of diabetic macular edema (DME) in this population. We aimed to estimate the long-term risk of DME and associated factors in patients with T1D. Methods: This retrospective cohort study included 235 patients with T1D from a tertiary center in Portugal. Demographic and clinical data were extracted from digital medical records and analyzed using descriptive statistics. Kaplan-Meier survival analysis was used to estimate time-dependent DME risk. Potential predictors of DME including age at T1D diagnosis, duration of T1D, glycated hemoglobin (HbA1c), body mass index (BMI), severity of diabetic retinopathy (DR), systolic and diastolic blood pressure (SBP and DBP), and smoking habits, were analyzed using multivariate Cox regression. Results: The overall prevalence of DME was 18.7%. The cumulative risk of developing DME escalated from 7.6% at 20 years to 51.1% at 65 years of T1D duration (p<0.001). Patients with severe or proliferative DR had a significantly higher prevalence of DME (p<0.001). Age at T1D diagnosis (HR: 1.03, 95% CI [1.00-1.06]; p=0.029) and DR severity (HR: 1.46, 95% CI [1.20-1.77]; p<0.001) were the strongest predictors of DME. HbA1c and SBP were associated with DME only in univariate analysis. Conclusions: This study highlights the time-dependent nature of DME development in T1D, with a marked increase in risk beyond 20 years of disease duration. DR severity remains a key predictor of DME, underscoring the need for timely intervention in long-standing T1D.