Endocrine Abstracts

Objective: IGF1 is the most useful serum marker for GH dose titration in adults. The authors focused on the GH dose adjustment with extreme IGF1 values (<−2S.D.; >+2S.D.).

Methods: French observational study of AGHD patients treated with Norditropin^®.

Prospective follow up until 5 years.

Results (median [Q1; Q3]):: 328 AGHD, 39.2±14.3 years old were included. GH median dose was 0.30 mg/d [0.20; 0.40]; IGF1 level was available in 97% of patients and was −0.9 S.D. [−7.2; 3.9]. Each year the GH dose modified in around 28% of patients (1^st year in 32.6%, 5^th year in 25.4%). At the end of the follow up the median GH dose was 0.40 mg/d [0.30; 0.60]. IGF1 measured annually in 80% of patients. Each year around 80% of patients had IGF1 between −2S.D. and +2S.D. During follow up 242 extreme IGF1 values were observed in 145 (44%) patients. And at N+1 visit no dose adjustment occurred in 72.2% (N=52) of patients with IGF1>+2SD (n=61) for a median dose 0.30 mg/d [0.20; 0.40] vs 49.3% (N=36) with IGF1<−2 S.D. (n=49) for a median dose 0.45 mg/d [0.40; 0.60] (Tables 1 and 2).

Conclusion: IGF1 was regularly measured in AGHD patients treated with GH in accordance with the guidelines and was in normal range for the majority. In this observational study, extreme IGF1 values were not systematically accompanied by dose adjustment. It could be explained by low GH dose prescribed and the fact that IGF1 is not the single factor of GH dose adaptation. Not taking in consideration at the visit with extreme IGF1 level the efficacy and tolerability of GH treatment is the limitation of this observation.