medwireNews: Three studies show that the risk of mortality and primary cancer is not increased in patients receiving recombinant human growth hormone (rhGH) treatment and that the risk of adverse events is not dose related.
The first of the studies, which appears in The Journal of Clinical Endocrinology & Metabolism, shows that the increased mortality risk among patients given rhGH treatment in childhood can be attributed to birth characteristics.
Kerstin Albertsson-Wikland (The Sahlgrenska Academy at University of Gothenburg, Sweden) and colleagues used a mortality model based on the Swedish population, which accounted for age, gender and year of birth. When applied to 3847 patients who began rhGH treatment between 1985 and 2010, this gave a standardised mortality ratio (SMR) of 1.43, with 21 deaths among the patients compared with an expected 14.68.
But an advanced mortality model, which also included gestational age, birth length and weight, and congenital malformations, predicted 21.99 deaths among the patients, giving an SMR of 0.955.
“This indicates that the increased mortality previously suggested to be linked to rhGH-treatment can be fully accounted for by differences in birth-characteristics”, says the team.
They stress that it also contradicts the assumption that, if left untreated, patients who have idiopathic GH deficiency or idiopathic short stature or are born small for gestational age will have a mortality risk similar to that of other healthy people.
In the second study, Christopher Child (Lilly Research Laboratories, Windlesham, UK) and co-researchers addressed the risk of primary cancers in 19,054 rhGH-treated patients in the Genetics and Neuroendocrinology of Short Stature International Study (GeNeSIS) who had no history of malignancy.
A total of 13 primary cancers occurred among the patients during 3.4 years of follow-up. Compared against the expected rates for the countries involved in the study, this gave a standardised incidence ratio of 1.02, indicating no increase in risk.
Writing in Hormone Research in Paediatrics, the researchers note that “interpretation of the results is somewhat difficult”, given the very small number of cases, despite the large sample size, but they stress that the findings are in line with those of other observational studies.
The final study, published in the European Journal of Endocrinology, found no association between rhGH dose and adverse event risk among 13,834 patients in the NordiNet® International Outcome Study, which Lars Sävendahl (Karolinska University Hospital, Stockholm, Sweden) and study co-authors describe as “reassuring”.
The patients received treatment for an average of 3.9 years, during which 261 patients reported 302 adverse events.
Adverse events were more common in patients considered at high risk of mortality than in those considered at intermediate or low risk. However, among patients with adverse events the average daily rhGH dose prior to the event tended to be lower in high-risk patients, at 29.8 µg/kg, compared with 33.2 and 35.1 µg/kg in intermediate- and low-risk patients, respectively.
By Eleanor McDermid, Senior medwireNews Reporter
J Clin Endocrinol Metab 2016; Advance online publication
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