Kidney Function is Associated with Drusen Characteristics

Abstract

Purpose : Chronic kidney disease (CKD) has been associated with age-related macular degeneration (AMD). We aim to further investigate if kidney function is related to drusen characteristics independent of known risk factors.

Methods : The drusen characteristics were graded on 97 Spectralis spectral-domain optical coherence tomography (OCT) B-scans for 811 subjects from the population-based Leipzig Research Center for Civilization Diseases (LIFE) adult study. The eye with worse drusen characteristics was selected if both eyes were available. Drusen type was graded into 3 categories and ordinally coded: none (0), only hard drusen (punctate elevation under retinal pigment epithelium [RPE] with sharp margins, 1) and presence of soft drusen (dome-shaped structures under RPE with indiscrete margins, 2). Drusen size was measured in horizontal meridian within RPE and classed into 4 groups ordinally coded: none (0), small (<63 μm, 1), medium (≥63 but <125 μm, 2) and large (≥125 μm, 3). The estimated glomerular filtration rate (eGFR) as assessed by the CKD-EPI equation was compared by drusen type and size with t-test corrected for multiple comparisons. Optimal models predicting drusen characteristics were selected by stepwise regression from eGFR and known risk factors of age, sex, blood pressure, glycated hemoglobin A1c (HbA1c), antidiabetic treatment, and smoking status. Partial correlations between eGFR and drusen characteristic adjusting for risk factors remaining in the optimal models were evaluated.

Results : The mean (standard deviation) of age for the 811 subjects (395 female) was 58.4 (10.8) years. Fig. 1 (a) and (b) show examples of drusen type and size graded on OCT. Fig. 2 (a) and (b) displays the eGFR distributions by drusen type and drusen size, respectively. Deteriorating kidney function with lower eGFR was significantly correlated to more severe drusen type (r = -0.10, p = 0.004) adjusting for age, sex, HbA1c, and smoking status, and significantly correlated to larger drusen size (r = -0.11, p = 0.002) adjusting for age, sex, and smoking status. Notably, Worsening kidney function significantly (p < 0.05 for both) contributed to the presence of hard/small drusen prior to early AMD compared to no drusen adjusting for known risk factors.

Conclusions : Impaired kidney function is related to severe drusen type and size independent of known risk factors, and contributes to the early formation of hard/small drusen prior to early AMD.

This abstract was presented at the 2019 ARVO Imaging in the Eye Conference, held in Vancouver, Canada, April 26-27, 2019.

 

Fig. 1

 

Fig. 2