Renal Dysfunction in the Presence of Normoalbuminuria in Type 2 Diabetes: Results from the DEMAND Study

BACKGROUND/AIMS: Microalbuminuria is associated with diabetes and is an independent risk factor for developing diabetic nephropathy. We have previously reported the overall prevalence of normoalbuminuria, microalbuminuria, and macroalbuminuria to be 51, 39, and 9.8%, respectively, in an unselected population of patients with type 2 diabetes. Renal dysfunction was present in a large proportion of these patients without proteinuria, assessed by a single random albumin-to-creatinine ratio (ACR). We therefore undertook to characterize the nature of this association of non-proteinuric renal dysfunction in type 2 diabetes. METHODS: In the DEMAND (Developing Education on Microalbuminuria for Awareness of Renal and Cardiovascular Risk in Diabetes) study, a global, cross-sectional study which described the prevalence and risk factors for albuminuria in a clinic-based cohort, kidney function was assessed in 11,573 patients; ACR was measured using the Bayer reagent strip Multistix® 10SG. Normoalbuminuria was defined as ACR <30 mg/g, microalbuminuria as 30-299 mg/g, and macroalbuminuria as >300 mg/g. RESULTS: Among the patients with estimated kidney function determined, chronic kidney disease was noted in 17% of those with normoalbuminuria (stage 3-5), and significant kidney dysfunction was found in 27% of those with microalbuminuria and 31% of those with overt proteinuria. CrCl was <60 ml/min in 20.5% of normoalbuminurics, 30.7% of microalbuminurics, and 35.0% of macroalbuminurics (p < 0.0001). CONCLUSION: A large proportion of diabetic patients with completely normal urinary albumin excretion or microalbuminuria presented with significant kidney dysfunction. Therefore, further investigation is warranted.