Response to Growth Hormone Treatment in Isolated Growth Hormone Deficiency versus Multiple Pituitary Hormone Deficiency

Background: Growth hormone (GH) therapy successfully increases height prognosis in children with GH deficiency (GHD); however, adult height data are still limited. Aim: This study investigated near-adult height (NAH) in patients with idiopathic GHD (i.e. those with a GH peak <10 µg/l with no organic pathology) divided into two groups: isolated GHD and multiple pituitary hormone deficiency (MPHD). Methods: All patients were registered in the Pfizer International Growth Study Database (KIGS). Median (10th to 90th percentile) values are given and measurements were expressed as standard deviation scores (SDS). Parental-adjusted height was determined. Results: GH therapy was started at a median age of 9.2 (range 4.9–12) years in patients with isolated GHD (n = 1,619, 60% males) and at 7.7 (range 2.8–12.2) years in those with MPHD (n = 554, 65% males; p < 0.001) at a median dose of 0.20 mg/kg/week. Height SDS at onset of therapy was –3.1 (range –4.5 to –2.1) and –3.8 (range –5.7 to –2.3), respectively (p < 0.001). The maximum GH peak and insulin-like growth factor I SDS were significantly (p < 0.05) lower in patients with MPHD than in those with isolated GHD. Both groups showed a significant (p < 0.05) increase in height SDS at 1 year that continued until the onset of puberty. Parental-adjusted height at the start of puberty was –0.1 (range –1.6 to 1.1) in patients with isolated GHD and –0.4 (range –1.9 to 1.2) in those with MPHD. Parental-adjusted NAH SDS in patients with isolated GHD was 0.0 (range –1.5 to 1.2) and slightly, but significantly, higher than NAH (–0.3, range –2.1 to 1.2; p < 0.001) in patients with MPHD. In patients with isolated GHD, total change in height SDS while receiving GH therapy was 1.6 (range 0.5–3.2), and the change in height SDS at puberty was 0.1 (range –0.7 to 1). The respective values were 2.6 (range 0.9–4.6) and 0.2 (range –1 to 1.3) in patients with MPHD. Parental-adjusted NAH was slightly lower in girls than in boys with isolated GHD, but no gender difference was observed in patients with MPHD. Multivariate analysis in patients with GHD and MPHD showed that higher birth weight, taller parents, greater height at onset, first-year responsiveness, and predicted height velocity were the most important predictors of NAH. Conclusions: 89% of patients with isolated GHD and 81% of those with MPHD reached an NAH within their genetic potential while receiving GH therapy. Most of the height gain occurred during prepubertal years.