PHILADELPHIA, April 17 /PRNewswire-USNewswire/ -- Boys are twice as
likely as girls in the U.S. and Asia (mostly Japan) to receive recombinant
human growth hormone (rhGH) for growth hormone deficiency, illnesses that
affect height, and short stature of a non-medical nature. A smaller gender
difference exists in Europe, Australia and New Zealand, but in the rest of
the world short boys and girls are treated at the same rate. This indicates
a likely cultural bias for male height in some countries.
The study, by researchers from The Children's Hospital of Philadelphia
and Pfizer, is electronically available prior to publication in the Journal
of Clinical Endocrinology and Metabolism.
All children entered in the Pfizer International Growth Study (KIGS), a
database designed to document long-term outcomes and safety of
Genotropin(R), one of the three leading commercial brands of rhGH, were
categorized by gender, location, date and age of therapy initiation, and
diagnosis. Measures of national health status, health care expenditures,
general economic indices and mean adult heights were also compared.
Children were categorized into four geographic regions including the U.S.,
Europe/Australia/New Zealand, Asia and the "Rest of the World."
Recombinant human growth hormone has been available since 1985.
"Because reports found more U.S. males receiving rhGH in its first years of
availability, and rhGH use has increased considerably over the past 20
years, we thought it was important to get an up-dated look at the
gender-based patterns of use in the U.S. and how they compared to other
countries," said Adda Grimberg, M.D., lead author of the study and a
pediatric endocrinologist at The Children's Hospital of Philadelphia. "We
suspect that social and cultural pressures, combined with financial
constraints, contribute to the international differences in the gender
distributions of children treated with rhGH."
Historical trends revealed a consistent overall male predominance among
U.S. pediatric rhGH recipients at a nearly two-to-one ratio. The gender
ratio did not change significantly across the more than 20 years of rhGH
use. Males outnumbered females at all ages, especially during the second
decade of life. Because boys typically start puberty later than girls and
hit their growth spurt at a later stage of puberty, boys who lag behind
their peers are more likely to be perceived as having a growth problem.
The factor that most consistently affected the gender distribution was
the diagnostic indication for rhGH therapy. The greatest gender disparities
occurred for diagnoses without an identifiable cause, such as idiopathic
short stature and idiopathic GH deficiency because of the complexity of the
diagnostic tests. Prader-Willi syndrome, a genetic disease with multiple
benefits from rhGH therapy besides height, was the only indication with
gender equality in the U.S. Dr. Grimberg hypothesized, "when the decision
to treat involves an indication that relies more heavily on clinical
judgment, treatment patterns are more likely to highlight underlying
differences in social pressures for tallness."
Comparing the U.S. experience with global patterns revealed that Asia
(mostly Japan) had the greatest male predominance at 65 percent, followed
closely by the U.S. at 64 percent. Europe/Australia/New Zealand came third
at 55 percent. All three world regions exceeded 50 percent males, while the
rhGH recipients in the rest of the world regions, where rhGH is used far
less frequently, were 47 percent male. Similar to the U.S. data, global
gender distributions of rhGH depended on the specific reason the therapy
was initiated. The United Kingdom had the lowest male percentage of the top
10 country-based children prescribed Genotropin(R).
Dr. Grimberg's earlier research in referral patterns for growth failure
evaluations at a U.S. pediatric endocrinology clinic showed a disturbing
statistic: that 41 percent of the girls were found to have an underlying
disease that made them short, compared to 15 percent of the boys.
Conversely, 38 percent of the boys were within normal height ranges,
compared to 20 percent of the girls, and boys were referred for evaluation
about twice as often as girls.
A variety of diseases may cause growth failure - among them, hormone
deficiencies, Turner syndrome (a chromosome abnormality found only in
females) and gastrointestinal conditions such as celiac disease or
inflammatory bowel disease. For some, growth failure is the only symptom.
"Gender differences in the use of rhGH may be indicative of more general
gender differences in the diagnostic rates of diseases that present solely
with growth failure," cautioned Dr. Grimberg. Not all of these diseases are
treated by rhGH. For example, celiac disease is treated with a gluten-free
diet. If a short girl is less likely to be perceived as needing rhGH
treatment, she may also be less likely to undergo the diagnostic evaluation
that reveals her underlying celiac disease.
The manufacture of rhGH in 1985 changed the treatment of pediatric
growth failure. Prior to 1985, only children with the most severe growth
hormone deficiency were treated because of the very limited supply of human
pituitary GH. In 2003, the U.S. Food & Drug Administration (FDA) approved
the use of rhGH for the treatment of idiopathic short stature, for children
who are significantly shorter than their peers yet do not have an
identifiable underlying disease.
The Pfizer International Growth Study (KIGS) was created in 1987, and
the U.S. joined the database in 1996. It is the world's largest
post-marketing surveillance database of rhGH use.
Dr. Grimberg is funded by an NIH grant from the National Institute of
Diabetes, Digestive and Kidney Disease and an award from Children's
Hospital. Dr. Grimberg's coauthors were Elizabeth Stewart and Michael P.
Wajnrajch, M.D., both from Pfizer Global Pharmaceuticals.
About The Children's Hospital of Philadelphia: The Children's Hospital
of Philadelphia was founded in 1855 as the nation's first pediatric
hospital. Through its long-standing commitment to providing exceptional
patient care, training new generations of pediatric healthcare
professionals and pioneering major research initiatives, Children's
Hospital has fostered many discoveries that have benefited children
worldwide. Its pediatric research program is among the largest in the
country, ranking third in National Institutes of Health funding. In
addition, its unique family-centered care and public service programs have
brought the 430-bed hospital recognition as a leading advocate for children
and adolescents. For more information, visit http://www.chop.edu.
SOURCE The Children's Hospital of Philadelphia
 back to top
Related links:
http://www.chop.edu
CONTACT:
Joey Marie McCool of the Children's Hospital
of Philadelphia, +1-267-426-6070, McCool@email.chop.edu
|
