medwireNews: Long-term growth hormone (GH) replacement in children does not increase their later risk of mortality, shows a Danish national registry study.

More specifically, the researchers found no indication of an increased risk of cerebrovascular mortality. Such a risk was reported by the French team of the Safety and Appropriateness of Growth hormone treatments in Europe (SAGhE) study, although none was found in the Belgian, Dutch and Swedish SAGhE cohorts.

Agnethe Berglund (Aarhus University Hospital) and co-researchers describe the interpretation of mortality risk in GH replacement as “complex and challenging”.

“It is important to stress that the patients in our study represents a cohort of ‘true’ GH [deficiency] patients”, they write in Clinical Endocrinology.

By contrast, they point out, the SAGhE study includes children with idiopathic short stature and those born small for gestational age, who may have specific mortality risks. Furthermore, at least some patients probably had supraphysiological levels of GH during treatment, further complicating safety assessments.

In the current study, just one patient who received GH replacement died of cerebrovascular causes, and this patient had previously undergone irradiation for cancer.

The study included 494 patients with childhood-onset GH deficiency, who were each matched by age and gender to 100 population controls and followed up for a median of 19.9 years. Overall, these patients had a 7.51-fold increased mortality risk relative to the controls, and this was significant among the 76% of patients who received GH replacement as well as those who did not.

The increased mortality risk was evident for most disease categories examined, including neurology, cardiovascular and congenital malformations, but the main driver was cancer. The increased risk of cancer mortality remained after excluding patients whose GH deficiency was caused by a malignancy. However, among the remaining patients, 24 had undergone irradiation and, of the other nine patients who died of cancer, just three had received GH replacement, indicating that GH treatment was not a contributing factor to the increased cancer mortality.

Indeed, there was a significant reduction in cancer mortality risk among patients with GH deficiency who received GH replacement relative to those who did not, after accounting for irradiation, primary disease, adrenocorticotropic hormone insufficiency and year of diagnosis.

“Taken together these findings do not support the suggestion that GH treatment in itself increases the risk of mortality due to cancer”, concludes the team.

By Eleanor McDermid, Senior medwireNews Reporter

Clin Endocrinol 2015; Advance online publication

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