The definition of appropriate treatment populations depends in part upon the balance of specific benefits and risks. A preliminary report indicates that a low plasma level of IGF-1 may correlate with increased mortality in patients over 70 yr old (52), suggesting a potential benefit in treatments which elevate IGF-1. However, just as thyroid hormone replacement can worsen the prognosis of patients with "low-T3 syndrome," a recent study of high-dose GH treatment in critical illness, a state of GH resistance, showed a worse outcome in the GH treatment group (53). This is a somewhat different situation from the reduced GH secretion seen in aging, but it raises caution about the potential risks in reversing changes that may be in part adaptive.
At this early stage, the reported side effects of treatment studies using GHRH have been few compared to studies of the use of GH in aging. So far, published reports of GHRH treatment have reported no adverse effects upon fasting glucose, and a relatively low incidence of clinical side effects such as edema or carpal tunnel syndrome. The number of subjects and the duration of treatment are still small, however, and it is also still not clear whether this generally favorable experience reflects the qualitative differences between GHRH and GH, or simply the differences in the effective potency of the doses used. As in the pediatric setting, there has been no direct comparison between GH and GHRH treatment in doses that produce similar increments in circulating GH.
Was this article helpful?