Growth hormone deficiency is no longer just a condition of childhood. The significant derangements in many metabolic parameters and the potential serious consequences of untreated growth hormone deficiency in adulthood, including increased cardiovascular mortality, have raised awareness of growth hormone as a hormone that influences much more than growth, and growth hormone deficiency as a condition that disrupts much more than height. Consequently, the standard pediatric approach to treatment of growth hormone deficiency, which focuses myopically on linear growth and ends at attainment of adult height, needs to be reexamined. This review addresses key issues surrounding the transition of the patient with growth hormone deficiency from the end of childhood to the beginning of adulthood.
A number of factors are predictive of persistence of growth hormone deficiency after childhood, including the etiology and age at onset of childhood growth hormone deficiency, number of additional pituitary hormone deficits, reflecting severity of pituitary dysfunction, and serum concentrations of insulin-like growth factor I and insulin-like growth factor binding protein-3. There are many negative consequences of discontinuation of growth hormone at attainment of final height, and patients with severe growth hormone deficiency should probably continue therapy uninterrupted through the transition phase. Patients in this phase of development require higher growth hormone doses than adults, and responses to growth hormone therapy are significantly influenced by gender.
The transition phase represents a newly defined developmental stage that serves to complete the aspects of physical and metabolic development that remain immature after attainment of adult height. As such, the physiology and pathology of this group of patients differ from those in childhood or in adulthood. Assessment and treatment of patients in this phase of life should acknowledge that these patients are not just “older children” or “younger adults,” but that they are a unique and separate group with distinct and different needs.
Lilly Research Laboratories, Indianapolis, Indiana, USA.
Charmian A. Quigley, MBBS, FRACP, Lilly Research Laboratories, Drop Code 5015, Lilly Corporate Center, Indianapolis, IN 46285, USA; e-mail: email@example.com