Treatment of Pre-pubertal Patients with Growth Hormone Deficiency: Patterns in Growth Hormone Dosage and Insulin-like Growth Factor-I Z-scores.
OBJECTIVE
To describe the range of insulin-like growth factor-I (IGF-I) z-score values (IGF-Iz) and growth hormone (GH) dose adjustments in pre-pubertal patients with GH deficiency (GHD) treated with GH in a single tertiary care center.


METHODS
This is a retrospective review of GH-treated patients of ages ≤9 years with GHD, seen in an endocrinology clinic in 2013-2014. Patient demographics and pre-treatment anthropometrics, GH treatment duration, IGF-Iz, and GH dosage (mg/kg/week) were extracted. Multipredictor linear regression was used to evaluate the associations between IGF-Iz and GH dosage and subject gender, race, insurance type, age, and clinical characteristics. Logistic regression was used to calculate the odds ratio of direction of GH dose adjustment (decrease/no change versus increase) and IGF-Iz category based on patient clinical characteristics, accounting for provider random effect.


RESULTS
Forty-one percent (57/139) of IGF-Iz were outside the "normal" range of between -2 and +2 standard deviation; the majority of IGF-Iz beyond the "normal" range (93%) were supraphysiologic [>+2 standard deviation score (SDS)]. Of the IGF-Iz >+2, 10/53 (18%) were followed by a GH dose increase and 30/53 (57%) had no dose change. Patient clinical characteristics and demographics did not significantly increase the odds of being in the IGF-Iz >+2 SDS category or having a dose increase in multipredictor logistic regression models.


CONCLUSIONS
GH dosages and IGF-Iz varied, without significant patient clinical predictors. IGF-Iz was frequently supraphysiologic, and these levels often did not prompt a reduction in GH dose, likely influenced by a variety of factors. Our study emphasizes the need for better understanding of long-term safety and efficacy of maintaining supraphysiologic levels of IGF-Iz.
The Children's Hospital of Philadelphia, Division of Endocrinology and Diabetes, Philadelphia, PA, USA.
Megan
M
Oberle
Adda
A
Grimberg
Vaneeta
V
Bamba
D002648:Child; D004393:Dwarfism, Pituitary / Q000188:drug therapy*; D005260:Female; D019382:Human Growth Hormone / Q000008:administration & dosage*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male; D012189:Retrospective Studies
D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I
Growth; growth hormone deficiency; growth hormone therapy clinical decision making.; insulin-like growth factor-I