Design and Statistical Aspects of the African American Study of Kidney Disease and Hypertension (AASK)

ABSTRACT. The African American Study of Kidney Disease and Hypertension (AASK) is a multicenter randomized clinical trial designed to test the effectiveness of three anti-hypertensive drug regimens and two levels of BP control on the progression of hypertensive kidney disease. Participants include African-American men and women aged 18 to 70 yr who have hypertensive kidney disease and GFR between 20 and 65 ml/min per 1.73 m 2 . The three anti-hypertensive drug regimens include an angiotensin converting enzyme inhibitor (ramipril), a dihydropyridine calcium channel blocker (amlodipine) or a beta-blocker (metoprolol) as initial therapy. The BP control levels are a lower goal (mean arterial pressure, ≤92 mmHg) and a usual goal (mean arterial pressure, 102 to 107 mmHg inclusive). The primary outcome is rate of change in renal function as measured by GFR, assessed by 125 I-iothalamate clearance. The main secondary patient outcome is a composite including the following events: ( 1 ) reduction in GFR by 50%, ( 2 ) end-stage renal disease, or ( 3 ) death. E-mail: jgassman@bio.ri.ccf.org