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.
