Association between early-stage chronic kidney disease and reduced choroidal thickness in essential hypertensive patients

The introduction in the past few years of advanced optical coherence tomography (OCT) techniques has greatly increased our understanding of the choroid, which is the most important vascular layer of the eye. Our study aimed to assess choroidal thickness by using swept-source OCT (SS-OCT) in essential hypertensive patients (EHs) with and without early-stage chronic kidney disease (CKD). We enrolled 100 EHs, of whom 65 were without kidney damage, and 35 had stage 1-3 CKD. In all of the participants, SS-OCT and a routine biochemical workup were performed. Glomerular filtration rate (GFR) was estimated by the CKD Epidemiology Collaboration equation (eGFR). CKD was defined in agreement with the Kidney Disease Outcomes Quality Initiative Kidney Disease: Improving Global Outcomes 2002 guidelines. OCT measurements were performed according to the Early Treatment Diabetic Retinopathy Study (ETDRS) protocol, which divides the macula into nine subfields. The circular grid consists of three concentric rings. EHs with CKD showed thinner choroidal thicknesses than those without it (all p < 0.05), even after adjustment for potential confounding factors. Overall choroidal thickness correlated significantly and directly with eGFR (r = 0.36) and negatively with urinary albumin excretion (r = -0.39). The association of choroidal thickness with CKD was confirmed in multiple logistic regression analyses once the effects of age and other confounding variables were accounted for. The odds ratio of having early-stage CKD associated with a standard deviation increase in overall choroidal thickness was 0.43 (0.24-0.75, 95% confidence interval; p = 0.007). In conclusion, our study confirms the close relationships between changes in ocular microcirculation and renal dysfunction.