Abstract
In patients with hypertensive nephrosclerosis, the African American Study of Kidney Disease and Hypertension (AASK) demonstrated the superiority of angiotensin-converting enzyme inhibitor therapy in blunting progression of renal disease compared with a b blocker and a dihydropyridine calcium channel blocker. In addition, the study found that a blood pressure treatment strategy that resulted in an achieved blood pressure of 128/78 mm Hg (low blood pressure goal) was no more effective in slowing the progression of renal disease than a strategy that resulted in a blood pressure of 141/85 mm Hg (usual blood pressure goal). AASK, which enrolled only African Americans with mild to moderate chronic renal insufficiency, also provided an opportunity to evaluate recruitment methods in minority populations. Eighty-three percent of patients were recruited through screening in clinical practice. To randomize 635 patients, 558,295 charts were reviewed (approximately 879 charts per randomized patient). More than half of the randomized patients (n=635 or 58%) were found by chart review. Sixty percent of women with creatinine levels considered within the normal range had at least mild chronic renal insufficiency. Screening in clinical practice was the most effective strategy to recruit participants with mild to moderate chronic renal insufficiency and hypertension into the clinical trial. This technique may also be an effective approach in trials of other essentially asymptomatic conditions.