Starting growth hormone therapy early in PWS tied to better body size outcomes
Infants, younger patients 'may benefit greatly' from growth hormone treatment
Children with Prader-Willi syndrome (PWS) who start on treatment with growth hormone in the first year of life tend to have more normal growth parameters like height and weight, a new study reports.
“This longitudinal study showed that younger children with PWS may benefit greatly from [growth hormone] treatment and that early [growth hormone] treatment had a more favorable outcome in height/length and body composition,” researchers wrote.
The study, “Effects of early recombinant human growth hormone treatment in young Chinese children with Prader–Willi syndrome,” was published in the Orphanet Journal of Rare Diseases.
People with PWS are often shorter and heavier than general population
People with PWS are commonly shorter than those without the disease, and they tend to be heavier as well. Treatment with human growth hormone has been shown to help normalize body size parameters, as well as improve cognition and motor outcomes for people with PWS. However, “the timing of starting [growth hormone] treatment is still controversial,” the researchers wrote.
In this study, scientists in China reported on outcomes for 96 children with PWS who started on treatment with growth hormone in the first years of life. Specifically, 65 began treatment as infants (before 1 year of age), while the other 31 started treatment as toddlers (ages 1 to 2 years). All of the patients were treated with recombinant (lab-made) versions of human growth hormone, referred to as rhGH. In both groups, most participants had a deletion of paternal genes on chromosome 15, the most common cause of PWS.
“To our knowledge, this is the first large sample study of rhGH treatment in younger children in China,” the scientists wrote.
This longitudinal study showed that younger children with PWS may benefit greatly from [growth hormone] treatment and that early [growth hormone] treatment had a more favorable outcome in height/length and body composition.
To assess growth parameters, the researchers calculated standard deviation scores (SDS) — a statistical measure of how a given individual compares with normative averages for a measurement like height or weight.
In both groups, the average SDS for both height and weight was low compared to normative values prior to starting on growth hormone. After the initiation of rhGH, SDS for height and weight gradually began to increase toward normative values in both groups of patients.
In the group that started treatment in infancy, SDS for height reached near-normal values by the age of 1 year. By comparison, the increase in SDS for height was significantly slower among patients who started on rhGH as toddlers, not reaching the normal range until around age 4.
“Our results showed that early rhGH treatment may reach the normalization height earlier than later treatment,” the researchers concluded. They noted that “early rhGH treatment significantly improved the final height required further longer follow-up, as this cohort was only followed up to 4 years old.”
The SDS for weight or weight normalized according to height also tended to normalize more quickly in the early treatment group, though the difference was not statistically significant.
Body size in early treatment group was closer to normal range
“Although the differences in weight and weight for height were not significant, we noted that the weight and weight for height were closer to the normal range in the early treatment group,” the researchers wrote.
Rates of spine abnormalities such as scoliosis were similar in the two groups.
Safety outcomes were also generally similar between the two groups. A total of 13 patients experienced low thyroid function (hypothyroidism) and two had signs of liver damage, but there was no difference in the rate of these side effects based on the timing of treatment initiation. None of the patients in the study developed diabetes, which is a potential concern with growth hormone therapy.
“Thyroid dysfunction, liver dysfunction, and scoliosis should be monitored during rhGH treatment, and the risk of adverse effects will not increase for PWS patients starting rhGH therapy in infancy,” the researchers wrote.