Retinal Vessel Geometry and the Incidence and Progression of Diabetic Retinopathy

Purpose: To analyze the associations between retinal vessel geometry and the 1-year incidence and progression of diabetic retinopathy (DR) in a Chinese population. Methods: This was a prospective cohort study of adult subjects with diabetes mellitus. Retinal vascular geometry was quantified from fundus photographs using a semiautomated computer-assisted program. Diabetic retinopathy was graded from retinal photographs at baseline and 1 year. Incident DR and 2-step change in DR were analyzed. Results: In total, 249 subjects were included. Their mean age was 59.9 ± 8.9 years, 74% were male, and the mean glycated hemoglobin A1c (HbA1C) and duration of diabetes were 7.7 ± 1.4% and 14.3 ± 10.6 years, respectively. The distribution of DR severity at baseline was no DR in 35.7%, minimal nonproliferative diabetic retinopathy (NPDR) in 15.3%, mild NPDR in 14.6%, moderate NPDR in 23.1%, severe NPDR in 5.1%, and proliferative DR in 6.1% of eyes. In multivariate analyses adjusting for age, duration of diabetes, sex, smoking status, HbA1c, hypertension, and hyperlipidemia, subjects with higher venular fractal dimensions were more likely to have incident DR (odds ratio [OR] 0.38, [95% confidence interval (CI), 0.15-0.96], P = 0.032, per SD decrease). Lower venular tortuosity was associated with a lower likelihood of DR progression (OR 0.76, [95% CI, 0.59-0.97], P = 0.005, per SD decrease). Lower arteriolar tortuosity was associated with a greater likelihood of DR regression (OR 1.95, [95% CI 1.07-3.56], P = 0.037, per SD decrease). Conclusions: Novel measures of retinal vascular geometry are associated with the incidence and progression of DR at 1 year. These geometric measures are likely to represent early dysfunction in the retinal microvasculature.