Rate of decline of GFR and progression of vascular disease in type 2 diabetic patients with diabetic or vascular nephropathy during the last three years before starting dialysis therapy.

BACKGROUND: The progression of chronic renal insufficiency depends on the type of primary renal disease and blood pressure (BP) levels. We investigated the rate of decline of glomerular filtration rate (GFR) during 3 years prior to the start of dialysis therapy in type 2 diabetic patients with diabetic nephropathy (dNP) or vascular nephropathy (vNP). The aim of the study was to determine differences in the progression of renal insufficiency and the prevalence of vascular diseases in the two patient groups.

METHODS: In a retrospective study, we investigated type 2 diabetic patients with chronic renal insufficiency who were undergoing regular controls in our outpatient care unit for at least 3 years prior to the start of dialysis. We evaluated only patients who had already died under chronic dialysis therapy, and whose diagnosis of primary renal disease was histologically conformed at autopsy. A total of 40 type 2 diabetic patients were included in the study. Of these, 28 patients had dNP (age 62 +/- 8 years) and 12 had vNP (age 70 +/- 7 years). The following parameters were determined at 3- to 6-month intervals: body weight, BP, HbA1c, serum creatinine (Cr), Cr clearance (Cockroft formula), cholesterol and triglycerides. The prevalence of vascular disease in the two groups was also assessed.

RESULTS: The average decrease in Cr clearance was 7.7 +/- 2.4 ml/min/year in patients with dNP and 7.7 +/- 2.1 ml/min/year in those with vNP (NS). During the entire observation period, mean HbA1c values (7.0 +/- 0.8 vs. 6.8 +/- 0.6%), systolic BP (137 +/- 8 vs. 138 +/- 11 mm Hg) and diastolic BP (86 +/- 4 vs. 87 +/- 7 mm Hg), cholesterol and triglycerides did not differ significantly in the two groups. The prevalence of vascular disease 3 years prior to and at the start of dialysis therapy was similar in patients with dNP and vNP.

CONCLUSION: The progression of dNP and vNP is similar at least during 3 years before the start of dialysis therapy. Vascular risk factors and the prevalence of vascular diseases were not significantly different in the two patient groups. However, diabetic patients with ESRD secondary to dNP were significantly younger than those with vNP.