Kidney Disease substantially worsens in
a fourth of African-Americans despite
therapy for Hypertension
The best available treatment for chronic
kidney disease from high blood pressure
did not keep the disease from
substantially worsening in about a
fourth of African-Americans studied,
according to long-term results of a
National Institutes of Health study
published in the
Archives of Internal Medicine.
The largest and longest study of chronic
kidney disease in African-Americans —
the African American Study of Kidney
Disease and Hypertension (AASK) — found
that the disease substantially worsened
in about one-fourth of participants,
even with very good blood pressure
control and use of kidney-protecting
medications, currently the best
available treatment.
This subgroup of patients either lost
half their kidney function or reached
kidney failure, also known as end-stage
renal disease.
"Despite these sobering results, blood
pressure control is still vital in
kidney disease and in many other
diseases," said NIH Director Elias A.
Zerhouni, M.D.
"But this research clearly signals the
importance of preventing kidney disease,
better understanding causes and finding
better ways to manage it in the 26
million Americans who already have it."
Good news also emerged from the study.
About one-third of participants
experienced a slow decline in kidney
function, about what is generally
observed with aging.
"The
factors that may be responsible for such
a small loss of kidney function need to
be studied," said Lawrence Y. Agodoa,
M.D., senior author of the study and
director of kidney failure research at
NIH’s National Institute of Diabetes and
Digestive and Kidney Diseases (NIDDK),
which funded the study.
The AASK Cohort Study observed about 750
African-Americans on recommended therapy
for chronic kidney disease from 2002 to
2007.
Study participants were initially
recruited beginning in 1995 for the AASK
Clinical Trial
www.nih.gov/news/pr/nov2002/niddk-25.htm,
which concluded in 2001 that an ACE
inhibitor medication protected the
kidneys better than two other classes of
blood pressure drugs.
During the Cohort Study, nearly 9 out of
10 participants were taking an ACE
inhibitor or an angiotensin receptor
blocking drug, and average blood
pressure was 133/78 mmHg, close to
national guidelines for high blood
pressure in people with chronic kidney
disease.
Uncontrolled high blood pressure, an
increase in the number of people with
diabetes, and the aging of the U.S.
population means more people than ever
are getting and living with kidney
problems.
About 13 percent of the U.S. population,
up from 10 percent in 1994, now have
chronic kidney disease.
And in 2005, more than 485,000 people
were on chronic dialysis or had a kidney
transplant for kidney failure, costing
Medicare, private insurers and patients
$32 billion.
Diabetes and high blood pressure are
leading causes of kidney disease, which
runs in families and disproportionately
affects African-Americans and American
Indians.
The condition can lead to kidney
failure, premature death, heart attacks,
strokes, bone disease, and growth and
developmental problems in children.
Blood and urine tests are the only way
to find kidney disease early, when
treatment is more likely to
significantly delay or prevent kidney
failure.
Important therapies that help protect
the kidneys include careful control of
high blood pressure — and blood sugar in
people with diabetes — ACE (angiotensin-converting
enzyme) inhibitors or ARBs (angiotensin
receptor blockers) to reduce protein in
the urine, and therapies to reduce the
risk of cardiovascular disease, which
increases the risk of developing kidney
disease.
Learn more about early detection and
treatment from NIDDK’s National Kidney
Disease Education Program at
www.nkdep.nih.gov or by calling
toll-free 1-866-4-KIDNEY
(1-866-454-3639).
The AASK Trial and Cohort Study were
conducted at 21 U.S. medical centers and
have been funded by NIDDK since 1994.
Additional support was provided by NIH’s
National Center on Minority Health and
Health Disparities and by King
Pharmaceuticals.
The National Institute of Diabetes and
Digestive and Kidney Diseases, a
component of the NIH, conducts and
supports research in diabetes and other
endocrine and metabolic diseases;
digestive diseases, nutrition, and
obesity; and kidney, urologic, and
hematologic diseases.
Spanning
the full spectrum of medicine and
afflicting people of all ages and ethnic
groups, these diseases encompass some of
the most common, severe, and disabling
conditions affecting Americans.
For more information about NIDDK and its
programs, see
www.niddk.nih.gov.
The National Institutes of Health (NIH)
—
The Nation's Medical Research Agency
— includes 27 Institutes and Centers and
is a component of the U.S. Department of
Health and Human Services. It is the
primary federal agency for conducting
and supporting basic, clinical and
translational medical research, and it
investigates the causes, treatments, and
cures for both common and rare diseases.
For more information about NIH and its
programs, visit
www.nih.gov