Anemia Tougher To Tackle In Black Children With Kidney Disease

Black children with chronic kidney disease have more severe anemia
than white children even when they receive the same treatment,
according to a multicenter study led by the Johns Hopkins Children's
Center to be published in the May issue of the American Journal of
Kidney Disease.

The findings suggest that inherent biological differences, rather
than access to care and treatment, may be at play, raising the
question whether current guidelines for anemia treatment should be
tailored to reflect race, investigators say.

Anemia, marked by abnormally low levels of red blood cells, is a key
indicator of disease status. It is diagnosed by measuring levels of
the protein hemoglobin, which carries oxygen in and out of red blood
cells. Hemoglobin levels below 11 grams per deciliter of blood
generally indicate anemia, but the number is adjusted for a child's
age and gender.

In the new study, black children with kidney disease had lower
hemoglobin than white children, 0.6 grams per deciliter on average,
and a greater proportion of black children were anemic when compared
with white children. The difference persisted even after researchers
eliminated certain factors that affect hemoglobin levels, such as
severity of kidney disease and whether the children received
treatment with hemoglobin-boosting medications for their anemia.

"As we move from one-size-fits-all medicine toward individualized
medicine, we should study further racial disparities and, perhaps,
adjust hemoglobin targets to reflect what appear to be genetic
variations," said lead investigator Meredith Atkinson, M.D., M.H.S.,
a pediatric nephrologist at the Johns Hopkins Children's Center.

Racial differences in hemoglobin levels are nothing new in adults
with chronic kidney disease, researchers say, nor are slight
variations in hemoglobin between healthy white and black children.

The tricky part, researchers say, is differentiating between "true"
anemia and normal racial variations in hemoglobin levels.

The Johns Hopkins-led study involved 429 children ages 1 to 16 with
chronic kidney disease enrolled in 44 study sites across the United
States. More than 40 percent of black children had hemoglobin levels
below the fifth percentile for their age and gender -- deemed a
critical cutoff point -- compared to 29 percent of white children.
Also, fewer African-American than white children reached higher
hemoglobin levels with treatment. The differences persisted even
after researchers controlled for factors affecting hemoglobin levels,
such as an iron-rich diet and body-mass index.

Moreover, researchers found that as the disease progressed and the
anemia got worse across the board for all children, the hemoglobin
gap between white and black children widened. This finding suggests
that as the disease progresses, pediatric nephrologists should
monitor even more vigilantly hemoglobin levels in their
African-American patients.

"What we are observing could very well mean that black children's
hemoglobin levels start to plummet once they reach a certain point in
their disease," Atkinson said.

Untreated, chronic anemia can speed disease progression and, over
time, can lead to a dangerous thickening of the heart muscle called
left-ventricular hypertrophy, among other complications.

Chronic kidney disease affects 26 million people in the United States.

The research was funded by the National Kidney Foundation and the
Thrasher Research Fund.

Conflict of interest disclosure: Meredith Atkinson received funding
from Amgen Inc., which manufactures anemia treatment medications,
among other products. The terms of this arrangement is managed by The
Johns Hopkins University in accordance with its conflict-of-interest policies.

Co-investigators in the study included Christopher Pierce,
M.H.S., and Rachel Zack, B.A., of the Johns Hopkins Bloomberg School
of Public Health; Gina-Marie Barletta, M.D., Helen DeVos Children's
Hospital in Grand Rapids, Mich.; Ora Yadin, M.D., Mattel Children's
Hospital at University of California-Los Angeles; Mark Mentser, M.D.,
Ohio State University; Bradley Warady, M.D., Children's Mercy
Hospital in Kansas City, Mo., and Susan Furth, M.D., Ph.D.,
Children's Hospital of Philadelphia.