The Association of Estimated Glomerular Filtration Rate With Diabetic Retinopathy and Macular Edema

Abstract

Albuminuria, a marker of diabetic kidney disease, is closely associated with diabetic retinopathy (DR) and diabetic macular edema (DME). However, the relationship between estimated glomerular filtration rate (eGFR) with DR and DME remains unclear, particularly in type 2 diabetes. We investigated the association of eGFR with DR and DME in a sample of patients with type 2 diabetes. We included 263 Caucasian patients with type 2 diabetes aged ≥ 18 years who participated in a clinic-based cross-sectional study in Melbourne, Australia. Diabetic retinopathy (n = 140) and DME (n = 61) were assessed from retinal photographs graded using the modified Airlie House classification and further confirmed with optical coherence tomography. Estimated glomerular filtration rate, assessed using the CKD-EPI formula, was analyzed continuously (per SD change) and categorically (normal renal function ≥ 90; impaired renal function, 60-89, and chronic kidney disease [CKD] < 60 mL/min/1.73 m2). When eGFR was analyzed categorically, impaired renal function and CKD were associated with the presence of DR when compared to normal renal function in multivariable models (odds ratio [OR] with 95% confidence interval [CI] of 2.97 [1.12-7.87] and 3.77 [1.28-11.10]), respectively. In DR severity analyses, CKD showed significant associations with moderate (5.83 [1.44-23.5], P-trend = 0.02) and severe DR (4.91 [1.26-19.0], P-trend = 0.04). These associations persisted when eGFR was analyzed continuously (P = 0.04). No significant associations were found between eGFR and DME. Our results suggest that lower levels of eGFR were associated with the presence and severity of DR, but not with DME.