Cross-sectional and Longitudinal Impacts of Chronic Kidney Disease on Retinal Ageing: An International Multi-Country Analysis

Abstract

Background Chronic kidney disease (CKD) is a risk factor for neurodegenerative diseases (NDDs), and ganglion cell-inner plexiform layer (GCIPL) thickness is an early and sensitive biomarker for NDDs, but previous studies have yielded conflicting results. Objective To assess the effect of CKD on GCIPL thickness in multi-country cohorts. Method This prospective observational study included 23,014 non-NDDs individuals from the UK Biobank, and three years of continuous follow-up data of 2,197 individuals from a Chinese cohort. Three groups were defined by eGFR based on serum creatinine classifying CKD severity as no CKD, Mild-CKD, and moderate-to-severe CKD (MS-CKD). The GCIPL thickness and its decline rate measured using optical coherence tomography. Results In the cross-sectional analysis, poorer renal function negatively correlated with GCIPL thickness with the mean decrease of 0.15 µm (95% CI -0.30 to -0.01; p = 0.038) in mild CKD, and 0.83 µm (95% CI -1.34 to -0.32; p = 0.002) in MS-CKD, compared to that of controls without CKD. Longitudinal analysis showed that the GCIPL decreased more rapidly in persons with poorer renal function. After correcting for confounders, the rate of GCIPL decline accelerated significantly as the CKD severity increased, by 0.30 µm/year (95% CI -0.41 to -0.19; p < 0.001) in mild CKD patients and by 0.52 µm/year (95% CI -0.79 − -0.26; p < 0.001) in MS-CKD, compared to controls without CKD. This relationship sustained in individuals with diabetes or hypertension. Conclusions Renal impairment accelerated the rate at which GCIPL thickness decreased over time, which hold across ethnicities and persons with varied health statuses.