(taken directly from the application) African-Americans suffer disproportionately from hypertension (HTN) and HTN-related end-stage renal disease (HTN-ESRD). An increasing but inconclusive body of evidence suggests that certain types of anti-HTN drug therapy and control of blood pressure to a lower level than is normal in clinical practice, may preferentially retard the progression of renal insufficiency and thereby delay or prevent the onset of HTN- ESRD. In response to RFA-DK-94-03 (African-American Study of Kidney Disease in Hypertension: Full Scale Trial) investigators from the Johns Hopkins Health Institutions propose to collaborate in the conduct of a full-scale clinical trial designed to test the comparative efficacy of three drug regimens (based on beta blocker, angiotensin converting enzyme inhibitor, and calcium channel blocker treatment) and two levels of blood pressure control (mean arterial blood pressure less than 92 versus 102-107 mmHg). The proposed study will be a double-blind clinical trial. The study population (100 percent African American) will consist of hypertensive men and women between the ages of 18 and 70, who have a mean glomerular filtration rate (GFR) between 25 and 70 milliliter (ml)/minute/1.73 meter squared (m2) and a presumed diagnosis of hypertension-related renal insufficiency. A minimum of 65 participants will be enrolled and randomized over a period of two years. They will be followed according to protocol for a period of approximately 4-6 years with close-out occurring in year 07. Following randomization, participants will be seen monthly and will have periodic laboratory evaluations including measurement of glomerular filtration rate by renal clearance of 125 iodine (I)-iothalamate on a quarterly basis. The primary outcome will be change in GFR during follow-up. The applicant considers strengths of this application to be a multi- disciplinary research team with acknowledged expertise in epidemiologic and therapeutic aspects of HTN and HTN-ESRD; extensive experience in the design, conduct, and analysis of collaborative clinical trials including special expertise based on participation in the AASK feasibility trial; participation of the Johns Hopkins Outpatient General Clinical Research Center; and a proven track record in the recruitment of African-American participants in NIH-supported, clinical trials of anti-HTN therapy.
