Clinical Predictors of Good/Poor Response to Growth Hormone Treatment in Children with Idiopathic Short Stature

Introduction: Children with idiopathic short stature (ISS) are known to have varying responses to growth hormone (GH) treatment (GHT). Methods: We conducted a post hoc analysis to identify clinical characteristics predictive of good and poor response during year 1 of GHT. Data from the NordiNet® IOS (NCT00960128) and the ANSWER Program (NCT01009905) were used. Patients were grouped according to their response to GHT; good, middle, and poor responders had a change in HSDS of >1.0, 0.4–1.0, and <0.4, respectively. Patients were also grouped according to their responsiveness to GH dose. Logistic regression modelling was performed to identify clinical characteristics predictive of response to GHT. Results: The response analysis set included 207 patients. Patients were 3–11 years old (males) or 3–10 years old (females) at treatment start and were prepubertal throughout year 1 of treatment. Age at treatment start (odds ratio [OR] 0.69, 95% confidence interval [CI] 0.5;0.9, p = 0.0169) and distance from target HSDS (OR 2.05, 95% CI 1.1;3.9, p = 0.0259) were found to be significant independent predictors of being in the good- versus poor-response groups. When patients were grouped according to their responsiveness to GH dose, a positive correlation between GH dose and change in HSDS was observed. Conclusion: We identified younger age and further distance from target HSDS as clinical predictors of response to GHT in a heterogenous population of children with ISS. Future studies, designed to identify the genetic determinants of response to GHT could further facilitate individualisation of GHT.