Design and Statistical Aspects of the African American Study of Kidney Disease and Hypertension (AASK) (original) (raw)
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Controlled Clinical Trials, 1996
In September, 2000, the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health called an early halt to the amlodipine arm of the African American Study of Kidney Disease and Hypertension (AASK) trial after careful deliberation by an independent data and safety monitoring board. An interim analysis of the AASK at 3 years revealed a renoprotective effect of the angiotensin-converting enzyme inhibitor ramipril as compared to the dihydropyridine calcium channel blocker (DHP-CCB) amlodipine in patients with mild to moderate renal insufficiency. This differential effect was independent of the blood pressure (BP) levels reached and was evident in proteinuric patients and suggestive in patients with baseline proteinuria < 300 mg/d, but was not conclusive. The AASK trial data suggest that DHP-CCBs should be used cautiously in the presence of mild to moderate renal insufficiency. Judgment should be reserved for the use of other CCBs, such as verapamil or diltiazem, since these are fundamentally different CCBs with the potential for a different impact on hypertensive nephrosclerosis. The blinded observation period for AASK will be completed at the end of September, 2001, at which time additional, clinically useful information is expected to become available. (c)2001 Le Jacq Communications, Inc.
Journal of Clinical Hypertension, 2004
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 β 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.