The National Institutes of Health (NIH) called an early halt to one arm of a study on the advice of an independent data and safety monitoring board after finding that people with kidney disease and protein in their urine were more likely to postpone kidney failure using either an angiotensin-converting enzyme (ACE) inhibitor or a beta blocker than a calcium channel blocker (CCB).
The ACE inhibitor ramipril (Altace®) or the beta blocker metoprolol (Toprol®) significantly reduced the risk of kidney failure compared to the CCB amlodipine (Norvasc®) in a group of patients who had at least one gram of protein in a 24-hour sample of urine when they joined the African American Study of Kidney Disease and Hypertension (AASK). Blood pressures were comparable.
Paradoxically, CCBs are one of two first-choice medicines for high blood pressure in African Americans1; 62 percent of AASK patients were on CCBs before joining the study. The type of CCB used in AASK, a dihydropyridine, was found in this study and in other recent studies to increase protein in the urine. Protein increases are linked with advancing kidney disease.
ACE inhibitors have been preferred for kidney disease of diabetes since 1994. Subsequent studies of other kidney diseases have found an association between protein in the urine and protection by ACE inhibition. Considered with the results of these other studies, AASK extends the value of ACE inhibitors to kidney disease of hypertension, at least for people with protein in the urine.
"This trial will have a tremendous effect on how we care for people," predicts Dr. Janice Douglas, chair of the study's steering committee and director of the hypertension division at University Hospitals of Cleveland and at Case Western Reserve University School of Medicine. "Most striking to me is the correlation between elevated urine protein and faster disease progression, something we can look for in all people with kidney disease," she explains. Dr. Douglas will present the study at the 33rd annual meeting of the American Society of Nephrology (ASN) in Toronto.
Dr. Lawrence Agodoa, a kidney specialist and NIH director of AASK, cautions patients to keep taking prescribed blood pressure medicine until they have worked out an alternative with their doctor. "Calcium channel blockers are good for controlling high blood pressure, and patients are not in immediate risk," he explains.
AASK will continue to compare the ACE inhibitor and beta blocker and to test whether a lower blood pressure target of 125/75 is more protective of the kidneys than 140/90. The CCB may be used as a secondary treatment if needed to reach blood pressure goals. AASK enrolled 1,094 African Americans at 21 centers and is scheduled to end in the fall of 2001.
African Americans make up 12.6 percent of the U.S. population but 29.8 percent of people treated for kidney failure. Hardest hit are blacks ages 25 to 44, who are 20 times more vulnerable to hypertension-related kidney failure. Better management of high blood pressure has led to fewer strokes and heart disease, but kidney failure is still increasing.
1 The 6th Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure, November 1997.
Notes to Editors:
The phone number for the ASN Press Room in Toronto
is 416-585-3715.
AASK is funded in part by the NIH Office of Research
on Minority Health.
Study drugs are provided by Pfizer, Monarch/King
Pharmaceuticals, and Astra USA.
ASSK Centers
Data Coordinating Center
The Cleveland Clinical Foundation, Ohio
Michael H. Kutner, Ph.D.
Phone: 216-444-0584
Jennifer J. Gassman, Ph.D.
Phone: 216-444-9938
Tom Greene, Ph.D.
Phone: 216-444-9933
Alabama
University of Alabama, Birmingham
Stephen G. Rostand, M.D.
Phone: 205-934-2646
California
King-Drew Medical College, Los Angeles
Keith Norris, M.D.
Phone: 310-668-4574
University of Southern California, Los Angeles
Shaul G. Massry, M.D.
Phone: 323-226-7337
University of California, San Diego
Daniel T. O'Connor, M.D.
Phone: 619-552-8585, ext.7373
Harbor-UCLA Medical Center, Torrance
Joel Kopple, M.D.
Phone: 310-222-3891
District of Columbia
Howard University Hospital, Washington, D.C.
Otelio S. Randall, M.D.
Phone: 202-865-1929 or 4881
Florida
University of Florida, Gainesville
C. Craig Tisher
Phone: 352-846-2473
University of Miami
Jacques J. Bourgoignie, M.D.
Phone: 305-243-6251
Georgia
Morehouse School of Medicine, Atlanta
William Cleveland, M.D.
Phone: 404-696-7300
Emory University, Decatur
Janice Lea, M.D.
Phone: 404-370-7340
Illinois
Rush Presbyterian St. Luke's Medical Center
University of Illinois, Chicago
George L. Bakris, M.D.
Phone: 312-942-3140
Maryland
The Johns Hopkins University, Baltimore
Lawrence J. Appel, M.D., M.P.H.
Phone: 410-955-4155
Michigan
University of Michigan, Ann Arbor
Kenneth Jamerson, M.D.
Phone: 734-747-0433
New York
Harlem Hospital Center, New York
Velvie Pogue, M.D.
Phone: 212- 939-1449
Mount Sinai School of Medicine, New York
Robert A. Phillips, M.D.
Phone: 212-241-4691
Ohio
Case Western Reserve University, Cleveland
Jackson T. Wright Jr., M.D., Ph.D.
Phone: 216-844-1109
Ohio State University, Columbus
Lee Hebert, M.D.
Phone: 614-293-4997
South Carolina
Medical Univ. of South Carolina, Charleston
DeAnna Cheek, M.D.
Phone: 843-792-2275
Tennessee
Meharry Medical College, Nashville
Marquetta Faulkner, M.D.
Phone: 615-327-6031
Vanderbilt University, Nashville
Julia A. Breyer Lewis, M.D.
Phone: 615-343-6105
Texas
University of Texas
Southwestern Medical Center, Dallas
John Middleton, M.D.
Interviews will be granted after 9 a.m., October 14, when the study will be
presented to the American Society of Nephrology plenary session attendees.
CONTACT:
Mary Harris
240-432-8039
After October 16,
301-496-3583
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) is part of the National Institutes of Health, Bethesda, MD