More Impact of Microalbuminuria on Retinopathy Than Moderately Reduced GFR Among Type 2 Diabetic Patients

OBJECTIVE: The current study aimed to investigate whether microalbuminuria or moderately decreased glomerular filtration rate (GFR) is a better predictor for the development and progression of retinopathy in type 2 diabetic patients. RESEARCH DESIGN AND METHODS: Type 2 diabetic patients without cardiovascular diseases, malignancy, pregnancy, and acute intercurrent illness were enrolled between 1 August 2001 and 31 December 2002. All participants provided their detailed medical history and underwent an eye fundus examination. They were followed up in outpatient clinics, and serum creatinine, urinary albumin-to-creatinine ratio (UACR), and retinal photographs were followed up annually until 31 December 2009. The primary outcomes were development and progression of diabetic retinopathy and nephropathy. The secondary outcomes were cardiovascular events and all-cause mortality. RESULTS: Among 487 participants, 81 subjects had normoalbuminuria and moderate renal impairment (baseline eGFR 30–59.9 mL/min/1.73 m(2)), and 106 subjects had microalbuminuria and baseline eGFR ≥60 mL/min/1.73 m(2). Patients with microalbuminuria and eGFR ≥60 mL/min/1.73 m(2) had a significantly greater risk for development and progression of diabetic retinopathy (HR 3.34 [95% CI 1.04–10.70]) compared with those with moderate renal impairment and normoalbuminuria after multivariate adjustment. Risks for renal outcome, cardiovascular events, and all-cause mortality were not significantly different between the two groups. CONCLUSIONS: Microalbuminuria has a greater impact on predicting the development and progression of diabetic retinopathy compared with moderate decline in GFR among type 2 diabetic patients.