Toto RD, Mitchell HC, Smith RD, Lee H-C, McIntire D, Pettinger WA
"Strict" blood pressure control and progression of renal disease in hypertensive nephrosclerosis

Kidney Int (Sep) 48:851-859 1995

Hypertensive nephrosclerosis is the leading cause of ESRD in African-Americans in the United States. Most of the patients with this diagnosis have not undergone renal biopsy, but recent studies suggest that clinical data are highly predictive of hypertension. Theoretically renal damage caused by systemic hypertension should be mitigated or abolished if blood pressure is sufficiently lowered. However, there are no large prospective clinical trials of antihypertensive therapy in patients with established hypertensive nephrosclerosis which have carefully analyzed the effect of blood pressure lowering on the rate of decline in glomerular filtration rate.

The purpose of this study was to measure the rate of decline in GFR in 87 patients with hypertensive nephrosclerosis randomized to two different levels of diastolic blood pressure: strict (N=42) < 80 mmHg versus conventional (N=35) 85-95 mmHg. All patients had long-standing hypertension and a baseline GFR of <70 (range 10-70) ml/min/1.73 m2, 53/77 were African-American and 29 were women. The patients were followed for a mean of 40 months. The mean rate of decline in GFR was not significantly different between groups despite a significant difference in mean follow-up diastolic blood pressure of about 6 mmHg. Remarkably the mean rate of decline in GFR for both groups was < 1.0 ml/min/year and neither rate was significantly different from zero. Analysis of the estimated decline in GFR suggested a trend to a slower decline in GFR in the "strict" group; however, this was not significant. Nine patients developed ESRD during follow up and 7 of these were African-Americans.

This is an exciting finding which has important implications for management of hypertensive nephrosclerosis as well as for the design of future clinical trials in hypertensive progressive renal diseases. Still, the study has several limitations including small sample size (limited power), limited follow-up, lack of demonstration of progression prior to randomization and small difference in mean follow-up diastolic blood pressure. Nevertheless, the data suggest that long-term control of diastolic blood pressure within the range of 81-87 mmHg can slow or arrest deterioration in renal function in patients with hypertensive nephrosclerosis. Since the majority of patients in this study were African-American, patients at highest risk for ESRD due to hypertension should benefit greatly from early, aggressive blood pressure control. (Toto)

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CRF by problem area : Progression
H: Pathophysiology : Kidney in hypertension