Antihypertensive treatment: long-term reversal of progression of albuminuria in incipient diabetic nephropathy. A longitudinal study of renal function.

This study was undertaken to clarify whether antihypertensive treatment has any effect on the rate of progression of kidney disease in patients with incipient diabetic nephropathy. Six insulin-dependent diabetic men with incipient nephropathy (urinary albumin excretion above 15 micrograms/min and total protein excretion below 0.5 g/24 h) were first given metoprolol (200 mg daily) with the subsequent addition of hydroflumethiazide. At the start of antihypertensive treatment, mean patient age was 32 +/- 4.2 years (SD) and mean duration of diabetes was 18 +/- 1.2 years. The patients were followed with repeated measurements of urinary albumin excretion for a mean of 5.4 +/- 3.1 years prior to, and for 4.7 +/- 1.3 years (SD) during treatment. Mean arterial blood pressure declined significantly during treatment, e.g., the values at 6 months before initiation of treatment being compared with values during the last 6 months of treatment fell from 107 mmHg +/- 7.6 to 93 +/- 3.8 (2p = 1.5%). Albumin excretion decreased from 131.0 micrograms/min X/divided by 2.9 (geometric mean X/divided by tolerance factor) to 41.7 micrograms/min X/divided by 2.9 (2p = 1.2%). Albumin clearance in per cent of glomerular filtration rate decreased from a mean of 0.0030 +/- 0.0019% (SD) to 0.0011 +/- 0.0010% (2p = 4.6%). The mean yearly increase in urinary albumin excretion before treatment was 18.0 +/- 17.0% (mean +/- SD); during treatment urinary albumin excretion decreased 19 +/- 10% per year (2p = 0.7%). No changes were seen in renal plasma flow (516 +/- 31.0 ml/min to 520 +/- 66 ml/min (n = 5)).(ABSTRACT TRUNCATED AT 250 WORDS)