Endocrine Abstracts

Introduction: GH deficiency (GHD) is associated with reduced bone mineral density (BMD) and treatment leads to its increase. BMD, a quantitative bone parameter, doesn’t bring whole information about bone status. Nowadays, bone quality shows as main determinant of bone strength, fracture prediction and treatment effect monitoring. A method to assess bone quality through the grey-level texture analysis from lumbar spine DXA scan is trabecular bone score (TBS).

Objectives: First, to assess the effect of recombinant human GH (rhGH) on BMD and TBS in GHD adults. Second, to analyse the factors influencing the effect of the therapy on bone.

Methods: A study of hypopituitary adults with GHD after 2 years of replacement treatment in IGF1 normalising regimen. Patients were divided according to gender, onset of GHD and etiology. They were adequately treated for other pituitary axis deficiencies and supplemented with calcium and vitamin D. TBS was derived from DXA scans of L-spine at baseline, month 12 and 24. Bone turnover markers (CTx and Osteocalcin) were evaluated at baseline, months 3, 6,12 and 24.

Results: 86 patients were included (mean 34.3 years, 48 males) mostly with GHD caused by surgery (n=46). After 2 years 14% (P=0.001) increase of L-spine BMD was observed, with higher increase in males (+16.4%, P=0.001) and childhood onset (CO) of GHD(+17.1%, P=0.008). TBS increased 2.3% (P=0.035) after first year and 3.1% (P=0.002) after second year with higher increase by CO (+5.02%, P=0.05) and no difference acording gender. Bone markers increased during the first 12 months of treatment with subsequent decrease of CTx.

Conclusion: Replacement with rhGH led to increase in bone mass and TBS associated with positive changes of bone turnover markers. Gender and onset of the GHD have shown as important predictors of bone microarchitecture resopnse to rhGH replacement.