ESPE Abstracts

Background: Male adolescents with severe GH deficiency show both loss of lean body mass (LBM) and gain of fat free mass (FFM) when off GH treatment. We recently showed that determining gain of FFM and loss of LBM by dual-energy x-ray absorption (DXA) is helpful in the diagnosis of severe GHD during transition as these body composition changes are correlated to the GH-peak of the arginine-GHRH-re-test.

Objective and hypotheses: We wanted to explore if the measurement of body composition by multi-frequency arm-to-leg bioelectrical impedance analysis (mf-BIA) can substitute DXA during transition.

Method: In total 40 male adolescents with childhood-onset GDH (age 14.7–19.6 years; mean 16.5±1.1 years)) underwent an examination of their body composition at time 0 and +6 month after stop of GH-treatment. At +3 month an arginine-GHRH-test was performed. A GH-peak less than 16 ng/ml indicated severe GHD. LBM and FFM were measured by DXA and mf-BIA at the same day under fasting conditions. The body composition changes score (BCC score) was calculated as the sum of gain of FFM and loss of LBM between time 0 and time +6 month.

Results: BIA failed at eight patients due to technical problems. Six patients were diagnosed with sGHD. All had a BIA-BCC larger than 4.5 kg and a DXA-BCC larger than 7.0 kg. Using these BCC scores as cut-offs, false positive BCC scores were found in eight of 28 patients (29%) with normal GH response using BIA and in two of 34 patients (6%) using DXA. The correlation of the GH-peak to BIA BCC score was lower (r=0.33) than to DXA BCC score (r=0.55).

Conclusion: BIA is comparably sensitive, but less specific than the gold-standard DXA in detecting body composition changes in male adolescents with severe GHD during transition.