Height Velocity Targets from the National Cooperative Growth Study for First-Year Growth Hormone Responses in Short Children

Abstract

Although GH has been used to treat short stature in GH deficiency (GHD) and other conditions for more than 40 yr, criteria for satisfactorily defining targets for GH responsiveness have never been developed. The objective of this study was to present the first-year growth expressed as height velocity (HV) for prepubertal boys and girls with idiopathic GHD, organic GHD, idiopathic short stature, or Turner syndrome from Genentech's National Cooperative Growth Study to derive age-specific targets for GH responsiveness for each etiology and gender. Using data from the National Cooperative Growth Study, we constructed curves of response to GH during the first year of treatment with standard daily doses in naive-to-treatment prepubertal children with idiopathic GHD (2323 males, 842 females), organic GHD (582 males, 387 females), idiopathic short stature (1392 males, 465 females), or Turner syndrome (1367 females). For each category, mean pretreatment and mean +/-1 and +/-2 sd for the first-year HV on GH were assessed. Mean and mean +/- 1 sd for HV were plotted vs. age at baseline (initiation of GH treatment) and compared with mean pretreatment HV. HV plots for each category as a factor of age at baseline are presented. Mean - 2 sd HV plots approximated the pretreatment HV. Using baseline age- and gender-specific targets will assist clinicians in assessing a patient's first-year growth response. We propose that HV below the mean - 1 sd on these plots be considered a "poor" response. These curves may be used to identify patients who may benefit from GH dose adjustment, to assess compliance issues, or to challenge the original diagnosis.