SHORT-TERM EFFECTS OF BLOOD-PRESSURE CONTROL AND ANTIHYPERTENSIVE DRUG REGIMEN ON GLOMERULAR-FILTRATION RATE - THE AFRICAN-AMERICAN STUDY OF KIDNEY-DISEASE AND HYPERTENSION PILOT-STUDY

The African-American Study of Kidney Disease and Hypertension pilot st udy randomized 94 nondiabetic black men and women (mean age, 53 years; 75% male) with presumed hypertensive nephrosclerosis and a baseline g lomerular filtration rate (GFR) of 25 to 70 mL/min/1.73 m(2) (mean, 52 .3 mL/min/1.73 m(2)) to blood pressure control at either a low mean ar terial pressure (MAP) goal of less than or equal to 92 mm Hg or a usua l MAP goal of 102 to 107 mm Hg and an antihypertensive drug regimen th at included either a calcium antagonist (amlodipine), a beta-blocker ( atenolol), or an angiotensin-converting enzyme (ACE) inhibitor (enalap ril). After 3 months of follow-up (n = 90), the mean GFR was similar ( 53.0 mL/min/1.73 m(2) v 53.7 mL/min/1.73 m(2)) to the baseline levels in participants randomized to the low MAP group (n = 44), whereas the mean GFR increased by 3.9 mL/min/1.73 m(2) (P = 0.02) in participants randomized to the usual MAP group (n = 46). During the same period of time, the mean GFR increased significantly in participants randomized to the calcium channel blocker regimen (n = 28) (5.7 mL/min/1.73 m(2); P = 0.01) but not in participants randomized to the beta-blocker regi men (n = 31) (1.7 mL/min/1.73 m(2); P = 0.10) or the ACE inhibitor reg imen (n = 31) (-1.1 mL/min/1.73 m(2); P = 0.52). Changes in GFR at 3 m onths were significantly different among the three treatment groups (P = 0.04). We conclude that the magnitude of short-term effects of bloo d pressure control and antihypertensive drug regimens on GFR should be considered when estimating sample size for clinical trials designed t o evaluate the effects of these interventions on long-term changes in GFR slope. (C) 1997 by the National Kidney Foundation, Inc.