Course of glomerular filtration rate in albuminuric type 2 diabetic patients with or without diabetic glomerulopathy

To evaluate and compare the clinical course and prognosis in type 2 diabetic patients with persistent albuminuria, with biopsy-proven diabetic glomerulosclerosis (DG), or with nondiabetic glomerulopathies (NDG).

A kidney biopsy was performed in 34 consecutive type 2 diabetic patients with persistent albuminuria (> or = 300 mg/24 h). Glomerular filtration rate (GFR) (51Cr-EDTA) was determined at least once a year, and albuminuria, arterial blood pressure, and HbA1c were determined every 3-6 months.

The biopsy revealed DG in 26 patients (25 men/1 woman) (DG group), age 52 +/- 2 (mean +/- SEM) years, and NDG in 8 patients (7 men/1 woman) (NDG group), age 54 +/- 3 years. The patients were followed for a median of 7.7 years (range 1.0-14.2). In the DG group, GFR decreased from 82 (24-146) to 38 (2-116) ml.min-1.1.73 m-2 (P < 0.001), with a median rate of decline in GFR of 5.6 (0.3-21.6) ml.min-1.year-1, and in the NDG group, GFR decreased from 107 (89-135) to 90 (17-119) ml.min-1.1.73 m-2 (P < 0.05), with a median rate of decline in GFR of 1.3 (0.3-7.6) ml.min-1.year-1 (P < 0.05 between groups). In the DG group, albuminuria increased from 1.4 (0.3-7.2) to 2.6 (0.1-21.6) g/24 h (P < 0.05) and in the NDG group, decreased from 2.2 (0.8-8.7) to 0.8 (0.2-2.5) g/24 h (P = 0.05). Mean arterial blood pressure (MABP) decreased from 118 +/- 3 to 104 +/- 3 mmHg (P < 0.05) in the DG group, whereas it remained unchanged in the NDG group (106 +/- 3 vs. 105 +/- 3 mmHg). In the DG group, the rate of decline in GFR correlated with systolic blood pressure (r = 0.62, P < 0.001), MABP (r = 0.52, P < 0.01), albuminuria (r = 0.55, P < 0.005), and GFR at entry (r = -0.45, P < 0.05).

Our study demonstrated a more rapid decline in GFR and a progressive rise in albuminuria in type 2 diabetic patients with DG compared with type 2 diabetic patients with NDG.