To compare end-stage progression of nephropathy in type 1 and type 2 diabetic patients and non-diabetic subjects, we prospectively studied 92 patients with advanced uraemia not yet on dialysis (mean age 57.2 +/- 15.0 years), with a serum creatinine level above 200 mumol/L. The study included monthly serum creatinine (SC) measurements and quarterly outpatient follow-up (mean 10.8 +/- 7.1 months, range 1-21). Sixty subjects (65.2%) were diabetic (28 type 1 and 32 type 2). At inclusion, 95.6% of patients had anti-hypertensive medications. Drug category, dosage and combination were similar for both groups. Blood pressure (< or = 130/85 mmHg) and glucose level targets (fasting < or = 7.5 mmol/L and postprandial < or = 10 mmol/L) were obtained in all patients. Initial SC was not significantly different between diabetic and non-diabetic patients (426.5 +/- 189.4 mumol/L vs. 405.1 +/- 201.9 mumol/L). SC increased significantly faster in diabetic than non-diabetic patients (respectively 3.9 +/- 6.1% and 1.5 +/- 4.6% monthly, p < 0.05), with no difference between type 1 and type 2 diabetes. One-third (33.7%) of all patients started dialysis during follow-up (40% diabetic and 22% non-diabetic). Their weight, body mass index, age, sex ratio, treatment and aetiology were similar. During follow-up, the patients (29.4%) who sustained a major vascular event differed only in age (62.1 years vs. 55.2 years; p < 0.001). In this study, diabetic renal disease worsened significantly faster than other nephropathies, in spite of proper normalisation of blood pressure and glucose level. Therefore, it is essential to diagnose and manage Type 2 diabetes early to avoid encumbering dialysis centres with older patients.