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 m² 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 m²) 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 m² 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.