|Chronic Kidney Disease Rises While Most People
with the Condition Remain Unaware
A growing number of Americans have chronic kidney disease, but
most remain unaware of it, hampering efforts to prevent irreversible
kidney failure requiring dialysis or a transplant, according to
a study funded by the National Institutes of Health and published
November 7 in the Journal of the American Medical Association.
An estimated 26 million people — about 13 percent of the
U.S. population — now have chronic kidney disease, say researchers
at Johns Hopkins University in Baltimore, Tufts-New England Medical
Center in Boston and Cleveland Clinic Foundation. The disease affected
an estimated 20 million people in 1994.
"Increases in diabetes, hypertension, obesity, and the aging
U.S. population explain at least some of the increase," says
co-author Paul W. Eggers, Ph.D., director of kidney disease epidemiology
at the National Institute of Diabetes and Digestive and Kidney
Diseases, part of the NIH. "We donít know what may be responsible
for the rest."
The study analyzed and compared National Health and Nutrition
Examination Survey data on adults age 20 or older from 1988 to
1994 and 1999 to 2004. More than 15,000 and 13,000 adults, respectively,
were interviewed at home and had a physical exam and blood and
urine tests. The surveys were conducted by the National Center
for Health Statistics, part of the Centers for Disease Control
Kidney function was estimated for each participant with a formula
that considers the amount of creatinine in a blood sample, along
with age, gender and African American race, which can affect results.
Creatinine is a waste product created by normal breakdown of muscle
cells during activity. When kidneys are ailing, creatinine builds
up in the blood. A small sample of urine was checked for a protein
called albumin. Damaged kidneys may persistently leak albumin from
the blood into the urine, sometimes even when kidney function appears
Awareness of chronic kidney disease is up, but most people who
have the condition still donít know it. Between 1999 and 2004,
survey participants were asked if they had been told they had "weak
or failing kidneys." The authors report that only 11.6 percent
of men and 5.5 percent of women with moderate (stage 3) kidney
disease knew it. Awareness increased to 22.8 percent among participants
with stage 3 disease and albumin in the urine. Awareness was highest
among people with severe (stage 4) kidney disease, only 42 percent
of whom knew they had the condition. Stage 5 is kidney failure.
"Kidney disease is often silent until late stages, but if
we can find it early we can do a lot to prevent kidney failure," explained
Andrew S. Narva, M.D., F.A.C.P., a kidney specialist at the NIH. "If
you have diabetes, high blood pressure or a family history of kidney
problems you are at risk and should be screened for kidney damage
with routine blood and urine tests."
"To help protect the kidneysí small blood vessels, carefully
control high blood pressure, and blood sugar if youíre diabetic,
and ask your doctor if you should take an angiotensin converting
enzyme inhibitor or angiotensin receptor blocker," advised
Narva, also director of the NIHís National Kidney Disease Education
Kidney disease raises the risk of early death, heart attack, stroke,
and high blood pressure; causes anemia, bone disease and malnutrition;
and can lead to kidney failure. In 2005, at least 107,000 Americans
learned they had kidney failure. That year, more than 485,000 had
dialysis or a kidney transplant, costing $32 billion, according
to the NIHís U.S. Renal Data System. The data system predicts that
by 2020 nearly 785,000 people will be receiving treatment for kidney
failure, costing $53.6 billion.
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.
Learn more about kidney disease education at www.nkdep.nih.gov,
diabetes education at www.ndep.nih.gov,
high blood pressure at www.nhlbi.nih.gov and
weight control at http://win.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.