ESPE Abstracts

Background: IGF1 is an important marker of GH treatment and is used to titrate the GH dose.

Objective and hypotheses: We report the correlation between the GH treatment induced increase in IGF1 and growth improvement in short children born small for gestational age (SGA).

Method: We recruited 13 pre-pubertal SGA children (eight boys, five girls) who received GH treatment. Eight continued treatment for >2 years. We retrospectively analyzed the correlation between the following parameters: i) IGF1 S.D. score increase (ΔIGF1 SDS) at 24 h, 1 or 2 years after GH treatment initiation; ii) height S.D. score increase (ΔHSDS) at 1 or 2 years.

Results: There was a significant positive correlation between ΔIGF1 SDS at 1 year and ΔHSDS at 1 year (r=0.61, P=0.027), and a positive correlation between ΔIGF1 SDS at 2 years and ΔHSDS at 2 years (r=0.65, P=0.079). Serum IGF1 levels were significantly elevated 24 h after the initiation of GH treatment (P=0.016). Although there was no significant correlation between ΔIGF1 SDS at 24 h and ΔHSDS at 1 year (r=0.075, P=0.82), there was a significant correlation between ΔIGF1 SDS at 24 h and ΔHSDS at 2 years (r=0.72, P=0.045).

Conclusion: As previously reported, the ΔIGF1 SDS induced by GH treatment was positively correlated with ΔHSDS. Importantly, there was also a correlation between the IGF1 increase 24 h after the initiation of treatment and growth improvement. Although IGF1 is affected by various factors such as nutrition status, the IGF1 increase 24 h after the initiation of GH treatment should reflect GH responsiveness independently of such factors. We conclude that IGF-1 at 24 h could be an important predictive factor for GH treatment-induced growth improvement.