Impacts of Chronic Kidney Disease on Retinal Neurodegeneration: A Cross-Cohort Analysis

Purpose: To assess the cross-sectional and longitudinal associations between chronic kidney disease (CKD) and ganglion cell-inner plexiform layer (GCIPL) thickness in a UK Biobank population and a Chinese cohort. Design: Prospective observational cohort study and cross-sectional study. Method: This study included 23,014 individuals without neurodegenerative diseases from the UK Biobank, and 3 years of annual follow-up data of 2197 individuals from a Chinese cohort. Three groups were defined by estimated glomerular filtration rate (eGFR) based on serum creatinine classifying CKD severity as no CKD, mild CKD, and moderate to severe CKD (MS-CKD). GCIPL thickness, measured using optical coherence tomography, was analyzed through linear regression over time to determine its decline rate in micrometers per year. Linear regression models were used to assess the correlation between renal function and both the baseline GCIPL thickness and the GCIPL decline rate. Results: The cross-sectional analysis in a largely white population showed that poorer renal function negatively correlated with GCIPL thickness with a mean of 0.15 µm thinner (95% confidence interval [CI] −0.30 to −0.01; P =.042) in mild CKD and 0.83 µm thinner (95% CI −1.34 to −0.32; P =.001) in MS-CKD compared with that of control subjects without CKD. Longitudinal analysis in the Chinese cohort showed that the GCIPL decreased more rapidly in persons with poorer renal function. After correcting for all confounding factors, the rate of GCIPL thinning was 0.30 µm/year (95% CI −0.41 to −0.19; P <.001) more in the mild CKD group and 0.52 µm/year (95% CI −0.79 to −0.26; P <.001) more in the MS-CKD group compared with control subjects without CKD. This relationship also occurred in individuals with diabetes or hypertension. Conclusions: Poor renal function was associated with a lower baseline GCIPL thickness in the UK population and a faster decline rate in Chinese participants. However, the detailed underlying mechanisms still need further exploration.