INVERSE RELATIONSHIP BETWEEN CHOROIDAL THICKNESS AND SUBCLINICAL RENAL DAMAGE IN ESSENTIAL HYPERTENSION

Abstract

The introduction in last years of advanced techniques of optical coherence tomography (OCT) has greatly increased our understanding of the choroid, that is the most important vascular layer of the eye. Our study was aimed to assess choroidal thickness by using Swept-Source OCT (SS-OCT) in essential hypertensive patients (EHs) with and without subclinical renal damage (SRD). We enrolled 100 EHs of which 65 without kidney damage and 35 with SRD. In all the participants SS-OCT and a routine biochemical workup were performed. Glomerular filtration rate (GFR) was estimated by the CKD-EPI equation (eGFR). SRD was defined, by the presence of microalbuminuria or eGFR between 30 and 60 mL/min/1.73 m2. OCT measurements were performed according to the Early Treatment Diabetic Retinopathy Study (ETDRS) protocol, that divides the macula into 9 subfields. The circular grid consists of 3 concentric rings. EHs with SRD showed thinner choroidal thicknesses than those without kidney damage (all p < 0.05), even after adjustment for age. 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 SRD was confirmed in multiple logistic regression analyses once the effect of age, antihypertensive therapy and triglycerides was accounted for. The odds ratio of having SRD associated with a standard deviation increase of 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.