Validated multivariate models predicting the growth response to GH treatment in individual short children with a broad range in GH secretion capacities

The aim of the study was to develop and validate models that could predict the growth responses to GH therapy of individual children. Models for predi ction of the initial one and 2-y growth response were constructed from a co hort of 269 prepubertal children (Model group) with isolated GH deficiency or idiopathic short stature, using a nonlinear multivariate data fitting te chnique, Five sets of clinical information were used. The "Basic model" was created using auxological data from the year before the start of GH treatm ent and parental heights. In addition to Basic model data, the other four m odels included growth data from the first 2 y of life, or IGF-I, or GH secr etion estimated during a provocation test (AITT) or a spontaneous GH secret ion profile, The performance of the models was validated by calculating the differences between predicted and observed growth responses in 149 new GH treated child ren (Validation group) who fulfilled the inclusion criteria used in the ori ginal cohort. The SD of these differences (SDres) in the validation group w as compared with the SDres for the model group. For the Ist y, the SDres fo r the Basic model was 0.28 SDscores. The lowest SDres (0.19 SDscores), givi ng the most narrow prediction interval, was achieved adding the 24h GH prof ile and data on growth from the first 2 y of life to the Basic model. The m odels presented permit estimation of GH responsiveness in children over a b road range in GH secretion, and with an accuracy of the models substantiall y better than when using maximal GH response during an provocation test. Th e predicted individual growth response, calculated using a computer program , can serve as a guide for evidence-based decisions when selecting children to GH treatment.