Endocrine Abstracts

GH replacement (GHR) in adults has demonstrated to improve body composition, inflammatory cardiovascular biomarkers and quality of life. However, this benefit is uneven, and factors that stratify treatment response are required.

According to current guidelines, low IGF-I levels in specific conditions provide strong evidence for GH deficiency (GHD). Nevertheless, normal levels do not exclude this diagnosis and make mandatory the use of GH stimulation testing. It has not been described before if GH deficient patients with normal IGF-I get the same clinical benefit from replacement as individuals with low IGF-I.

The aim of this study is to compare the response to GHR between the subgroup with normal IGF-I and patients with low IGF-I.

We analyzed retrospectively 34 GHD adults (mean age 40.4 years; 16 females) from our centre who received GHR for at least 2 years (mean duration of treatment 7.4 years). Anthropometric parameters, bone mineral density (BMD) of the lumbar spine and hip, and the scores in quality of life questionnaires (AGHDA and Nottingham) were measured before starting treatment and at the end of the follow-up. Differences in these parameters were tested by Mann–Whitney U test.

No significant differences were found in the baseline parameters between the subgroup with normal IGF-I and patients with low IGF-I.

The AGHDA and Nottingham mean scores improved significantly at the end of follow-up (−3 (SD 3.95) P=0.003 and −3.8 (SD 7.4) P=0.01 respectively) but there were no differences between patients with normal or low IGF-I (P<0.109 and P<0.533). No significant changes were observed in BMD or body composition.

Our data show that benefits of GHR are maintained across different scales of IGF-1 secretion. Thus, this study highlights the limitations of basal IGF-1 status in reflecting the physiopathology of GHD, indicating the severity of GHD and selecting candidates for replacement.