The effect of two different GH dosages on final height and bone geometry

BACKGROUND Growth hormone (GH) has a strong positive influence on bone, stimulating both bone elongation and increase in size. The aim of the study was to compare the effect of two different GH dosages on final height and bone geometry in two groups of GH-deficient children. METHODS We evaluated 121 children (86 m, 35f). Group 1 (77 patients) treated with GH at a mean dose of 0.16 mg/kg/week and group 2 (44 patients) at 0.3 mg/kg/week. Bone geometry was evaluated at final height from a digitalized X-ray of the left hand considering the following parameters: metacarpal index (MI), cross-sectional area (CSA), cortical area (CA) and medullary area (MA). RESULTS At baseline, group 2 was shorter than group 1 (-1.54 vs -1.01 SDS; p < 0.005), while at final height there was no difference. Height gain was significantly greater in group 2 than in group 1 (1.62 vs 1.13 SDS; p < 0.001). Bone geometry: MI was significantly greater in group 2 (0.62 vs 0.55; p < 0.001) as well as CA (46.87 vs 42.69 cm(2); p < 0.005), while MA was significantly lower in group 2 (8.48 vs 11.65 cm(2); p < 0.002). CONCLUSION Higher GH doses elicit a significantly greater statural gain and a greater bone cortical area.