Cerebral small-vessel disease is associated with the severity of diabetic retinopathy in type 1 diabetes.

Introduction Cerebral small-vessel disease is common in neurologically asymptomatic individuals with type 1 diabetes. The retinal vasculature is thought to mirror the brain’s vasculature, but data on this association are limited in type 1 diabetes. Our aim was to study associations between diabetic retinopathy severity and cerebral small-vessel disease in type 1 diabetes. Research design and methods For this cross-sectional study, we enrolled 189 participants with type 1 diabetes (median age 40 (33–45) years; 53% female; diabetes duration 21.6 (18.2–30.7) years) and 29 healthy age-matched and sex-matched controls as part of the Finnish Diabetic Nephropathy Study. Participants underwent a clinical investigation, brain MRI, and fundus imaging. Signs of cerebral small-vessel disease in brain MRIs were analyzed in relation to diabetic retinopathy severity (Early Treatment Diabetic Retinopathy Study (ETDRS) score). Results In type 1 diabetes, participants with cerebral small-vessel disease had higher ETDRS scores (35 (20–61) vs 20 (20–35), p=0.022) and a higher prevalence of proliferative diabetic retinopathy than those without cerebral small-vessel disease (25% vs 9%, p=0.002). In adjusted analysis, proliferative diabetic retinopathy was associated with cerebral small-vessel disease (OR 2.57 (95% CI 1.04 to 6.35)). Median ETDRS score (35 (20–65) vs 20 (20–35), p=0.024) and proliferative diabetic retinopathy prevalence were higher (29% vs 13%, p=0.002) in participants with versus without cerebral microbleeds. ETDRS scores increased by number of cerebral microbleeds (p=0.001), both ETDRS score (OR 1.05 (95% CI 1.02 to 1.09)) and proliferative diabetic retinopathy (8.52 (95% CI 1.91 to 37.94)) were associated with >2 cerebral microbleeds in separate multivariable analysis. We observed no association with white matter hyperintensities or lacunar infarcts. Conclusions Presence of cerebral small-vessel disease on brain MRI, particularly cerebral microbleeds, is associated with the severity of diabetic retinopathy.