Effect of antihypertensive treatment on progression of incipient diabetic nephropathy

Abstract

The aim of the study was to clarify whether antihypertensive treatment with a selective beta blocker would have an effect on the progression rate of kidney disease in patients with incipient diabetic nephropathy. Six male patients with juvenile-onset diabetes with incipient nephropathy (urinary albumin excretion above 15 μg/min and total protein excretion below 0.5 g/24 hr) were treated with metoprolol (200 mg daily). At the start of the antihypertensive treatment the mean age was 32 years ± 4.2 (SD). The patients were followed a mean 5.4 years ± 3.1 (SD) with repeated measurements of urinary albumin excretion before and during 2.6 years ±1.0 (SD) of treatment. The blood pressure was depressed by the treatment (systolic blood pressure from 135 mm Hg ± 8.6 to 124 mm Hg ± 6.2, NS; mean blood pressure from 107 mm Hg ± 7.6 to 97 mm Hg ± 3.4, Ip < 0.05; diastolic blood pressure from 93 mm Hg ± 9.1 to 84 mm Hg ± 3.6, Ip < 0.05. Albumin excretion decreased (131.0 μg/min × / ÷ 2.9 [geometric mean × / ÷ tolerance factor] to 56.1 μg/min × / ÷ 3.7, 2p < 0.02). The mean yearly increase in urinary albumin excretion before treatment was 18 ± 17 (mean ± SD). Albumin excretion decreased during treatment: 17% ± 15 per year (mean ± SD, Ip < 0.02). No changes were seen in glomerular filtration rate or renal plasma flow (149 ml/min ±. 5.8 vs 144 ml/min ± 11.1, and 516 ml/min ± 31.0 vs 541 ml/min ± 68.5 respectively [n = 5]). No side effects were seen. It is concluded that during antihypertensive treatment using a cardioselective beta blocker, blood pressure decreased and albumin excretion was reduced concomitantry. Glomerular filtration rate was unchanged during treatment. Antihypertensive treatment in the stage of incipient nephropathy may have a more beneficial effect on the progression of the kidney disease than when it is started in the overt stage of nephropathy, where glomerular filtration rate has already begun to decline. © 1985 American Heart Association, Inc.