High frequencies of diabetic micro- and macroangiopathies in patients with type 2 diabetes mellitus with decreased estimated glomerular filtration rate and normoalbuminuria.

Background: The clinical characteristics of diabetic patients presenting with normoalbuminuria with decreased kidney functions were investigated.

Methods: A cross-sectional study was performed in 1197 patients with type 2 diabetes mellitus. The estimated glomerular filtration rate (eGFR) was calculated using the formula recommended by the Japanese Society of Nephrology.

Results: The groups with normoalbuminuria, microalbuminuria, macroalbuminuria and renal failure consisted of 696 (58%), 229 (19%), 196 (16%) and 76 (6%) subjects, respectively. The frequencies of all diabetic micro- and macroangiopathies increased with progression of diabetic nephropathy stage. However, in the groups with chronic kidney disease (CKD) stage 3+4 (60 > eGFR > or = 15 mL/min/1.73 m(2)), the frequencies of diabetic neuropathy and macroangiopathies were not different among the groups staged by urinary albumin excretion. In the normoalbuminuria group, 223 (32%) cases showed CKD stage 3+4. Diabetic neuropathy and macroangiopathies were significantly more frequent in the groups presenting with normoalbuminuria with CKD stage 3+4 than in those with CKD stage 1+2 (eGFR > or = 60 mL/min/1.73 m(2)). The patients' age, duration of diabetes mellitus and frequency of hypertension were significantly higher in the groups presenting with normoalbuminuria with CKD stage 3+4. After adjustment by age, grade of albuminuria or both, CKD stage 3+4 was an independent risk factor for some diabetic complications.

Conclusions: The combination of urinary albumin excretion and eGFR is useful for earlier detection of kidney and vascular damage in patients with diabetes mellitus. Evaluation of eGFR should be performed for all diabetic patients even if they show normoalbuminuria.