Effects of long-term antihypertensive treatment on kidney function in diabetic nephropathy.

The purpose of our prospective study was to evaluate the long-term effect of aggressive antihypertensive treatment on glomerular filtration rate and albuminuria in young female and male patients with insulin-dependent diabetes mellitus with diabetic nephropathy and blood pressure greater than 90 mm Hg. Eight patients received treatment with metoprolol (200-400 mg/day), hydralazine (100-200 mg/day), and furosemide (80-500 mg/day). The untreated control group consisted of eight patients matched for age (mean 32 years), diabetes duration (mean 17 years), and sex (two female and six male patients). All patients except one had diabetic retinopathy. Glomerular filtration rate was measured after a single intravenous injection of 51Cr-labeled ethylenediaminetetraacetic acid. Urinary albumin concentration was determined with a radial immunodiffusion method. The investigations were performed two to four times per year in each patient. The mean observation period was 59 and 27 months in the treated and untreated groups respectively. Due to a considerable rise in arterial blood pressure, it was considered unethical to prolong the observation in the untreated group. Arterial blood pressure rose from 140/96 +/- 4/1 to 150/100 +/- 3/2 mm Hg; albuminuria increased from 1517 +/- 502 to 1911 +/- 120 micrograms/min; and glomerular filtration rate decreased by a mean of 0.84 +/- 0.17 ml/min/mo in the untreated group. Antihypertensive treatment induced blood pressure reduction 151/100 +/- 3/2 to 131/87 +/- 2/1 mm Hg; diminished albuminuria 1467 +/- 515 to 729 +/- 65 micrograms/min; and caused a slow rate of decline in GFR, mean 0.37 +/- 0.08 ml/min/mo.(ABSTRACT TRUNCATED AT 250 WORDS)