Parents considering treatment for this otherwise medically benign condition should know what this means: daily injections for years until the child is finished growing, 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 tests. Dr. Grimberg said, “Gives the child a strong message that something is wrong with him that needs fixing.”
According to the Pediatric Endocrine Society, the decision to give growth hormone for idiopathic short stature should be made on a case-by-case basis, carefully weighing the benefits and risks for each child.
Then what are the benefits and risks? Although manufacturers have supported drug safety monitoring beyond the 10 years required by the US government, reporting is voluntary and necessarily incomplete. However, a far more reliable assessment is available in Sweden, where population-wide data are routinely collected.
In December’s JAMA Pediatrics, pediatric endocrinologists at Karolinska University Hospital reported that among 3,408 patients treated with recombinant growth hormone as children and adolescents who were followed up for up to 25 years were at risk of a cardiovascular event such as a heart attack or stroke develop two-thirds higher in men and twice as high in women than in 50,036 untreated but otherwise similar people.
The Swedish finding follows a report from a team of researchers in Tokyo last June that growth hormone promotes biomedical pathways that stimulate the development of atherosclerosis, the basis of most cardiovascular events.
It is not yet known whether further long-term side effects will become noticeable in the coming years. Because of its known effects, the administration of growth hormone when there is no deficiency can increase the risk of cancer, respiratory diseases and diabetes. In an editorial in JAMA Pediatrics, Dr. Grimberg stated that “indirect evidence suggests that the potential for adverse effects from growth hormone treatment is sufficiently plausible” to warrant further studies.
It is just as important for parents to know how much height their children can gain from years of daily hormone injections. Although it is impossible for an individual child to predict this in advance, the average benefit for children with idiopathic short stature is about two inches from adult height. Dr. Grimberg suggested that parents should consider discontinuing treatment if there is no measurable benefit within a year of therapy.