Optical coherence tomography angiography biomarkers in diabetic nephropathy patients in Thailand : a diabetic eye and kidney diseases (dek-d) study

Abstract

Diabetes mellitus (DM) can cause many microvascular complications including diabetic retinopathy (DR) and diabetic nephropathy (DN). It is estamated that about one-third of diabetic patients have DR and about 40% have DN. DR and DN share a common pathology in microvasculature. With the development of optical coherence tomography angiography (OCTA), the examination of retinal capillary is more convenient and less invasive. This is a cross-sectional observational study aimed to identify OCTA parameters as biomarkers that predict the diabetic nephropathy and association with 24-hour urine albumin level in diabetic patients. 186 eyes from 93 individuals were divided into 3 groups according to 24-hour urine albumin level: no DN, early DN, and late DN. Vessel density (VD), fractal dimension (FD), foveal avascular zone (FAZ) area, intercapillary area, central retinal thickness (CRT), subfoveal choroidal thickness (CT) were measured from OCTA images to determine the association between DN status. VD values of superficial capillary plexus (SCP), deep capillary plexus (DCP), and whole retina were significantly lower in early DN group compared to no DN group (adjusted p-value 0.007, 0.003, and 0.003, respectively). VD values of DCP and whole retina were significantly decreased in late DN group compared to no DN group (adjusted p-value 0.032 and 0.021, respectively). Mean FD, intercapillary area, FAZ area, CRT, and subfoveal CT were not statistically different between 3 groups. VD may be a useful tool for non-invasive screening of DN. Further studies in larger population are needed to establish a cutoff value for detection.