Retinal vascular geometry and its association to microvascular complications in patients with type 1 diabetes: the Danish Cohort of Pediatric Diabetes 1987 (DCPD1987)

To examine associations between retinal vascular geometry (tortuosity, branching coefficient [BC] and length-diameter ratio [LDR]) and diabetic proliferative retinopathy (PDR), nephropathy, and peripheral neuropathy in patients with type 1 diabetes mellitus (T1DM). A cohort of patients with T1DM participated in a clinical examination in 2011. Blood and urine analyses were done and retinal images taken. PDR was defined as Early Treatment Diabetic Retinopathy Study level 61 or above, nephropathy as albumin-creatinin ratio >= 300 mg/g, and neuropathy as vibration perception threshold > 25 Volt. Retinal vessel parameters were measured using semi-automated software. Multiple logistic regressions were performed to investigate correlations between retinal vascular parameters and outcomes. Models were adjusted for other variables (sex, age, duration of diabetes, systolic and diastolic blood pressure, HbA1c, and presence of microvascular complications). Odds ratios were given per standard deviation in retinal vascular parameter. Retinal vascular analyses were performed in 181 patients. Mean age and duration of diabetes were 37.0 years and 29.4 years respectively, and 50.8% were male. Prevalence of PDR, nephropathy, and neuropathy were 26.5%, 6.8%, and 10.1% , respectively. Patients with increased arteriolar BC had a higher risk of nephropathy (OR: 3.10, 95% CI: [1.01-9.54]). Patients with increased venular BC had a higher risk of neuropathy (OR: 2.11, 95% CI: [1.11-4.03]). No associations were found in patients with PDR. By analyzing the retinal vascular tree in patients with T1DM, we found a higher risk of complications in kidneys and nerves when BC was increased. This might indicate a suboptimal construction of the vascular tree in these patients.