Study Finds Gender Bias in Growth Hormone Treatment for Height

Researchers from The Children’s Hospital of Philadelphia have found a clear-cut and persistent gender bias in the provision of treatment for idiopathic short stature (ISS) with recombinant human growth hormone treatment. The work, which was published recently in Scientific Reports, shows short boys are three times more likely than short girls to receive recombinant human growth hormone treatment for ISS.

The statistical definition for ISS (short stature from an unknown cause) height corresponds to the shortest 1.2 percent of the U.S. population. The study aims at understanding the origins of the disparities in the management of short stature.

“Social pressures regarding height seem to affect males more than females, at least in the U.S.,” said the study’s leader Adda Grimberg, MD, a pediatric endocrinologist at Children’s Hospital and a senior fellow of the Leonard Davis Institute of Health Economics at the University of Pennsylvania. “In the absence of an underlying condition, treating short children with recombinant human growth hormone represents medicalization of a physical trait.”

The research team looked at the health records from 28 primary care practices in the CHOP pediatric network, comprising 189,280 patients, and compared them to 93,736 patients from the four U.S. pediatric growth hormone registries. All the subjects were children and adolescents (up to age 20). In the primary care population, 2,073 subjects (1.1 percent of the total) had heights below the threshold for idiopathic short stature. There were no gender differences in the prevalence of height below this threshold, or in the distributions of height in the entire primary care population.

In contrast, among patients receiving recombinant human growth hormone for ISS, 74 percent were male. Among patients who received the hormone for all diagnoses, 66 percent were male. At the time of initiating growth hormone for idiopathic short stature, treated boys outnumbered girls for every year of age starting at age one, but the biggest differences occurred around puberty, when late bloomers and limited remaining time for potential medical intervention raise concern.

“Growth is an important sign of child health, so growth failure merits equal consideration for both boys and girls,” Dr. Grimberg said. “Gender bias in treatment may have doubly undesirable effects — short girls who have an underlying disease may be overlooked, while short healthy boys may receive overzealous, unnecessary treatment with an expensive drug that requires years of nightly injections and has potential side effects.”

Human growth hormone treatment costs roughly $20,000 per child per year, and requires daily injections.

In previous research, Dr. Grimberg found that proportionally more girls who were referred for evaluation of short stature were much more likely to have an underlying disease than boys who were referred. “The gender bias in referral and treatment suggests that diagnoses of underlying diseases are more likely to be delayed or missed altogether in short girls, and this suggests missed opportunities to address those conditions, not all of which require growth hormone treatment,” she said.

For more information, and for a link to the study in Scientific Reports, published online June 9, 2015, click here.