Relationship Between Renal Function and Choroidal Thickness in Type 2 Diabetic Patients Detected by Swept-Source Optical Coherence Tomography

Purpose To investigate the relationship between renal function and choroidal thickness (CT) in ocular treatment-naive patients with diabetes mellitus using swept-source optical coherence tomography (SS-OCT). Methods This cross-sectional study recruited type 2 diabetes mellitus (T2DM) patients with no history of ocular treatment from communities in Guangzhou, China. The estimated glomerular filtration rates (eGFR) were calculated by using the Xiangya formula. The impaired renal function was defined as eGFR < 60 mL/(min 1.73 m2). The choroid was imaged by using an SS-OCT, and the macular CT was quantified automatically in Early Treatment Diabetic Retinopathy Study maps, and only data from one eye was used. Univariate and multivariate linear regression analyses were performed to explore the influence of eGFR on CT. Results A total of 1395 patients with T2DM were included in the final analysis. The CT of all macular regions were significantly thinner in patients with renal impairment (all P < 0.001). A significantly positive correlation was observed between the average CT and eGFR (β = 0.4; 95% confidence interval, 0.041-0.8; P = 0.029) independent of age, sex, and other potential confounding factors. After adjusting for other factors, a higher eGFR was also associated with higher CT values in the central field (P = 0.019) and in the outer superior (P = 0.047), inner superior (P = 0.018), inner inferior (P = 0.025), and inner temporal (P = 0.038) regions. Conclusions CT decreased in parallel with renal impairment in ocular treatment naive diabetic patients, providing an accessible window for monitoring renal status. Translational Relevance Knowledge of association between retinal microvasculature and renal microcirculation would allow applying in both clinical and research settings.