Progression of Incipient Diabetic Nephropathy

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 /ig/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/xg/min x/-j2.9 [geometric mean x / + tolerance factor] to 56.1 /ig/min x/-s3.7, 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. (Hypertension 7 [Suppl II]: 11-109-11-113, 1985)