ObjectiveTo observe and analyze the correlation between macular microvascular parameters and urinary albumin to creatinine ratio (UACR) in patients with type 2 diabetes mellitus (T2DM). MethodsA cross-sectional study. From October 2017 to April 2018, 100 eyes of 100 patients (T2DM) and 27 eyes of 27 healthy controls (the control group) were enrolled in Xuzhou First People’s Hospital. All subjects underwent anterior segment examination via slit-lamp biomicroscopy, dilated fundus examination, 7-field fundus photographs, OCT angiography (OCTA), the fasting glucose test, glycosylated hemoglobin (HbA1c), urinary albumin, urinary creatinine and UACR levels determination. Height and weight measurement were taken for calculating body mass index (BMI). Diabetic retinopathy was ruled out by fundoscopic examinations and 7-field fundus photographs in T2DM patients. According to the UACR, patients in the T2DM group were subdivided into A1 group (UACR< 30 mg/g), A2 group (UACR 30-300 mg/g), and A3 group (UACR>300 mg/g), with 38 cases and 38 eyes respectively , 40 cases with 40 eyes, 22 cases with 22 eyes. A 6 mm×6 mm scanning area centered on the macular fovea were scanned for right eye using a frequency domain OCTA instrument, which were divided into three concentric circles centered on the macular fovea by the software automatically. The foveal zone was defined as a circular area measuring 1 mm in diameter, the parafoveal zone was described as a middle circle area measuring 1-3 mm in diameter, and the perifoveal zone was an outer circle area measuring 3-6 mm in diameter. The vessel density of superficial capillary plexus (SCP) and deep capillary plexus (DCP), foveal avascular area (FAZ) and perimeter (PERIM), non-circularity index (AI) were measured. The correlation between the macular vessel density, FAZ and UACR was analyzed by Spearman correlation analysis. ResultsA1 group, A2 group, A3 group, and normal control group. The macular area SCP and DCP (F=13.722, 5.644), foveal area (F=4.607, 4.719), parafoveal area (H=23.142, F=2.904), the blood flow density of the area around the fovea (F=12.292, H=10.946), the difference was statistically significant (P＜0.05); with the increase of UACR, the blood flow density of each area of SCP and DCP showed a downward trend. The results of correlation analysis showed that the blood flow density of the whole SCP, parafoveal area, and surrounding area of T2DM patients was negatively correlated with UACR (r=－0.376, －0.240, －0.364, －0.347, P＜0.05). There were no correlation among fasting plasma glucose, HbAlc and UACR (r=0.179, 0.085, P＞0.05). There were no correlation among blood flow density in BMI, SCP foveal area, DCP and UACR (|r|＜0.3, P＞0.05). ConclusionThe whole, parafovea and perifovea vessel density values of SCP in T2DM eyes without DR are negatively correlated with UACR.
ObjectiveTo investigate the characteristics of microcirculation parameter changes in the deep capillary plexus (DCP) of the macular region in patients with type 2 diabetes mellitus (T2DM) and to analyze their correlation with diabetic kidney disease (DKD). MethodsThis cross-sectional study included 133 eyes of 133 T2DM patients who visited Shanxi Eye Hospital from March 2022 to May 2024. According to the presence of DKD, the patients were divided into a DKD group (49 eyes of 49 patients) and a non-DKD group (84 eyes of 84 patients). All eyes underwent swept-source optical coherence tomography angiography examination, and 6 mm × 6 mm macular images were acquired. Microcirculation parameters of the superficial capillary plexus (SCP) and DCP were quantitatively analyzed, including vessel diameter (VD), vessel area density (VAD), vessel skeleton density (VSD), and non-perfusion area (NPA). The area of the foveal avascular zone (FAZ) was also measured. Intergroup comparisons were performed using the independent samples t-test or Mann-Whitney U test. Multivariate logistic regression was employed to analyze the independent association between microcirculation parameters of SCP and DCP and DKD after adjusting for diabetic retinopathy (DR) status. ResultsCompared with the non-DKD group, the DKD group showed significantly increased VD (Z=?3.885) and NPA (Z=?4.268), and significantly decreased VAD (t=2.883) and VSD (t=3.866) in the DCP layer (P＜0.05). No statistically significant differences were observed between the two groups in VD, VAD, VSD, NPA of the SCP layer, or the FAZ area (P＞0.05). After adjusting for DR, multivariate logistic regression analysis indicated that VD [odds ratio (OR)=2.513, 95% confidence interval (CI) 1.445-4.370] and NPA (OR=2.079, 95%CI 1.375-3.143) of the DCP were independent risk factors for DKD in T2DM patients (P＜0.05), whereas VAD (OR=0.810, 95%CI 0.696-0.943) and VSD (OR=0.433, 95%CI 0.271-0.691) of the DCP were protective factors (P＜0.05). ConclusionsIn T2DM patients, those with DKD exhibit characteristic microcirculatory alterations in the macular DCP, specifically increased VD and NPA, along with decreased VAD and VSD. These abnormalities in DCP microcirculation parameters are independently associated with the occurrence of DKD, suggesting their potential as imaging biomarkers for assessing renal complications in T2DM.
