The early progression of chronic kidney disease in
children and teens is poorly understood, but a national
research team led by Johns Hopkins scientists is launching
the largest-ever study to learn more about this often
stealthy killer.
"There has never, to our knowledge, been a study
designed to systematically assess the changes in kidney
function over time in children with early kidney disease
and to determine how these changes affect behavior,
learning, heart disease risk and growth," said Susan Furth,
a nephrologist at the
Johns
Hopkins Children's Center, one of the project's three
principal investigators and lead author of a report on the
study appearing in the Clinical Journal of the American
Society of Nephrology.
This NIH-funded 57-center study hopes to follow over a
period of four years 540 children ages 1 through 16 with
mild to moderate kidney disease. The Johns Hopkins
Children's Center is one of two clinical coordinating
sites, along with the Children's Hospital at the University
of Missouri, Kansas City. The
Johns Hopkins Bloomberg
School of Public Health is the study's data
coordinating center.
Researchers will collect blood, urine and fingernail
and hair samples and will monitor kidney function, height,
weight, blood pressure and heart disease by the use of
echocardiograms. Periodic surveys are planned to track
everything from quality of life and social and cognitive
development to sexual maturation, which is often delayed in
teens with kidney disease. Patients will fill out
questionnaires detailing everything from symptoms to use of
medications and dietary supplements to lifestyle and
exercise. Researchers will harvest cell lines to study the
genetic elements of kidney disease.
Results will be reported incrementally, but some
preliminary findings are already in. For example, using
data from the pilot study, researchers have refined an
existing method used mostly in Europe to measure the
kidneys' filtering capacity, the most precise indicator of
kidney function and status.
The new, improved method, which measures how fast the
kidneys clear an injected contrast agent from the blood,
promises to become the new gold standard for kidney
function estimates in clinical trials and will also help
researchers refine existing formulas that doctors use for
children, which yield faulty results 25 percent of the
time.
Kidney disease in children tends to start and evolve
silently. More than one-third of kidney transplant patients
in 2001 were between the ages of 20 and 44, and the
majority likely developed the disease in childhood,
researchers say. An estimated 650,000 Americans will
develop end-stage renal disease by 2010, costing the health
care system $28 billion a year.
Co-investigators in the study from Johns Hopkins are
Alvaro Muñoz and Stephen Cole, both of the Bloomberg
School of Public Health.
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