Parents considering treatment for this otherwise medically benign condition should know what it entails: daily injections for years until the child’s growth is completed, rotating injection sites in the body to minimize scarring. Although few children experience side effects, which can include severe headaches and hip problems, treatment requires repeated doctor visits, X-rays and blood work and, Dr. Grimberg said, “gives the child a powerful message that there’s something wrong with him that needs fixing.”
According to the Pediatric Endocrine Society, the decision to administer growth hormone for idiopathic short stature should be made on a case-by-case basis in which benefits and risks are carefully considered for each child.
What, then, are the benefits and risks? Although manufacturers have supported monitoring drug safety beyond the 10 years mandated by the U.S. government, reporting is voluntary and necessarily incomplete. However, a far more reliable assessment is available from Sweden, where population-wide data are routinely collected.
In JAMA Pediatrics in December, pediatric endocrinologists from Karolinska University Hospital reported that among 3,408 patients who were treated with recombinant growth hormone as children and adolescents and followed for up to 25 years, the risk of developing a cardiovascular event like a heart attack or stroke was two-thirds higher for men and twice as high for women than among 50,036 untreated but otherwise similar people.
The Swedish finding follows a report last June from a research team in Tokyo that growth hormone promotes biomedical pathways that stimulate the development of atherosclerosis, the basis for most cardiovascular events.
Not yet known is whether other long-term adverse effects will become apparent in the years ahead. Based on its known action, giving growth hormone when no deficiency exists might raise the risk of cancer, respiratory disease and diabetes. In an editorial in JAMA Pediatrics, Dr. Grimberg wrote that “indirect evidence suggests that the potential for untoward effects of growth hormone treatment is sufficiently plausible” to warrant further study.
Equally important for parents to know is how much height their children might gain from years of daily hormone injections. Though impossible to predict in advance for an individual child, the average benefit for children with idiopathic short stature is about two inches in adult height. Dr. Grimberg suggested that if there is no measurable benefit within a year of therapy, parents should consider stopping it.