Abstract
INTRODUCTION: Age-related decline in glomerular filtration rate (GFR) significantly contributes to chronic kidney disease (CKD). This longitudinal study in a nondiabetic population investigated whether retinal microvascular changes are associated with GFR decline. METHODS: The Renal Iohexol Clearance Survey (RENIS) included 1837 participants aged 50 to 62 years without self-reported diabetes, kidney or cardiovascular disease. Baseline retinal vessel measurements and retinopathy were assessed with a Visucam PRONM retinal camera. Iohexol clearance was measured over 1 to 4 visits across an 11-year median follow-up. Linear mixed models and logistic regression were used to analyze associations between retinal vessel measurements, retinopathy, mean annual GFR decline, and accelerated GFR decline. RESULTS: In multiple adjusted linear mixed models, wider central retinal venular equivalent (CRVE) and wider central retinal arteriolar equivalent (CRAE) were associated with a steeper mean measured GFR (mGFR) decline. For each SD increase, CRVE was associated with an mGFR decline of -0.08 ml/min/yr (95% confidence interval [CI]:-0.15 to -0.02; P = 0.012), and CRAE was associated with a decline of -0.09 ml/min/yr (95% CI:-0.15 to -0.02; P = 0.007). CRVE, but not CRAE, was associated with accelerated mGFR decline in the model adjusted for age, sex, and height [OR 1.31 (95% CI 1.07-1.61, P = 0.008]. No significant associations were observed between retinopathy, microaneurysms, and hemorrhages with annual or accelerated mGFR decline. CONCLUSION: CRVE and CRAE, but not retinopathy, retinal microaneurysms, or hemorrhages, were associated with steeper mean mGFR, suggesting that microvascular changes may be one of the underlying mechanisms for age-related GFR loss in a general nondiabetic population.