Increased Risk of Renal Deterioration Associated with Low E-GFR in Type 2 Diabetes Mellitus Only in Albuminuric Subjects

Objective: The significance of estimated glomerular filtration rate (e-GFR) in diabetic nephropathy has yet to be clearly determined. We therefore compared albuminuria and e-GFR for usefulness in predicting progressive decline in renal function.

Methods: A total of 1,303 subjects with type 2 diabetes mellitus whose e-GFR was more than 30 mL/min/1.73 m(2) were followed for three years. Associations of clinical staging based on AER and that based on e-GFR with progression of renal insufficiency (e-GFR <30 mL/min/1.73 m(2)) were evaluated.

Results: On univariate analysis, both clinical stages based on e-GFR and AER were significant variables (p<0.05). On multiple logistic regression analysis, the odds ratio for macroalbuminuria was 132.3, and that for microalbuminuria was 10.3 while that for e-GFR less than 60 mL/min/1.73 m(2) was 9.0 for further deterioration of renal function. On the other hand, subjects without albuminuria exhibited a rate of disease progression of less than 1% irrespective of e-GFR level.

Conclusions: Both albuminuria and reduced e-GFR are significant and independent risk factors for further deterioration of diabetic nephropathy, though albuminuria had a greater odds ratio than reduced e-GFR for deterioration of renal function over a three-year period. e-GFR exhibited additive risk for deterioration of diabetic nephropathy within three years only when albuminuria was present.