Attaining genetic height potential: Analysis of height outcomes from the ANSWER Program in children treated with growth hormone over 5 years

Objective: This study aimed to assess attainment of genetic height potential after long-term growth hormone (GH) treatment in GH-naïve children diagnosed with isolated growth hormone deficiency (IGHD), multiple pituitary hormone deficiency (MPHD), born small for gestational age (SGA), or idiopathic short stature (ISS) enrolled in the American Norditropin® Studies: Web-enabled Research (ANSWER) Program. Design: Children with IGHD (n = 2884), MPHD (n = 200), SGA (n = 481), or ISS (n = 733) with baseline height standard deviation score (HSDS). ≤- 2 were assessed over 5 years of GH treatment for mean HSDS, change in HSDS (δHSDS), and corrected HSDS (HSDS - target HSDS). Results: Mean HSDS and corrected HSDS significantly increased to close to target height across all diagnostic groups after 5. years of GH treatment (P< 0.0001). ∆HSDS at year 5 increased for all groups (IGHD: 1.8; MPHD: 2.1; SGA: 1.8; ISS: 1.6). Among patients who continued GH for 5. years, mean insulin-like growth factor-I (IGF-I) SDS increased to within normal range across all groups. Body mass index (BMI) SDS remained relatively stable in all diagnostic groups. Bone age (BA) increased, and the mean BA to chronological age (BA/CA) ratio reached or approached 1 across diagnostic groups over 5. years of GH treatment. Conclusions: Long-term GH therapy resulted in a significant increase in mean HSDS and corrected HSDS from baseline values in all diagnostic groups. The observed increase in mean corrected HSDS is consistent with growth that approached the patients' genetic height potential, although complete height gains will be evaluated at the attainment of final height.