Relationship between diabetic retinopathy and vascular endothelial function in elderly type 2 diabetic Japanese patients without cardiovascular disease

Background:   Many recent studies point to the importance, in diabetic patients, of vascular endothelial function as an early marker of not only macrovascular complications but also of microangiopathy. The aim of this study is to investigate the relationship between diabetic retinopathy and endothelial function in elderly diabetic patients by using brachial artery flow-mediated dilation (FMD).
Methods:   We studied 71 type 2 diabetic patients aged 65 years or older without cardiovascular diseases. The subjects were categorized as three groups: (i) without diabetic retinopathy ( n  = 49); (ii) with non-proliferative diabetic retinopathy group ( n  = 15); and (iii) those with preproliferative or proliferative diabetic retinopathy ( n  = 7). Brachial artery FMD measurement was performed by high-resolution ultrasonography. The Kruskal–Wallis test, the χ² test and multivariate logistic regression analysis were used to identify associations between both retinopathy and clinical characteristics and FMD.
Results:   There were no differences in clinical characteristics between the three groups. FMD of the three groups were significantly decreased correlating with the severity of retinopathy (8.03% vs 5.40% vs 2.30%; P  = 0.003). Multivariate logistic regression analysis showed that there was a significant correlation between diabetic retinopathy and FMD (odds ratio 0.801; P  = 0.009).
Conclusion:   Our study suggests that FMD has a relation to microangiopathy in elderly diabetic subjects. Prospective studies will be required to determine whether this test has any clinical use for identifying elderly diabetic patients who are likely to develop diabetic retinopathy.