Optimizing growth hormone efficacy: an evidence-based analysis

For almost two decades, recombinant growth hormone (GH) has been in abundant supply to treat GH-deficient subjects to final height, yet the results continue to be suboptimal. Although there are numerous potential causes for this underachievement, the issues of poor compliance, ineffective dosing and lack of efficacy monitoring have been frequently promulgated to explain the phenomenon. Compliance is tied to knowledge, which is best promoted at the time of diagnosis by hospital-based personnel. GH pens have improved acceptability, but data on improvement in compliance are lacking. No GH device or delivery system has yet been shown to increase final height. Daily (or six times per week) dosing is clearly more effective, but increasing GH dose, especially during puberty, has a tendency to advance bone age and pubertal progression, which mitigates many of the effects. Finally, titration of dose to the insulin-like growth factor (IGF)-I level may prove to be useful in promoting final height; however, the converse is not true, i.e. increments in IGF-I level have not been shown to correlate with increments in height velocity. Thus, these issues with respect to achievement of final height are far from solved.