Background: The precision of adult height prediction by bone age determination in children with idiopathic growth hormone deficiency (IGHD) is unknown.
Methods: The near adult height (NAH) of patients with IGHD in the KIGS database was compared to adult height prediction based on the Bayley Pinneau (BP) in 315 children and based on the Tanner-Whitehouse 2 (TW2) method in 121 children. Multiple linear regression analyses adjusted for age at GH start, mean dose and years of of GH treatment, and maximum GH peak in stimulation test were calculated.
Results: The mean underestimation of adult height based on the GP method was at baseline 4.0±0.5cm in girls and 4.4±0.4cm in boys, at 1 year of GH treatment 2.0±0.3cm in girls and 0.5±0.3cm in boys, while at last bone age determination adult height was overestimated in mean by 0.4±0.4cm in girls and 3.7±0.3cm in boys. The mean underestimation of adult height based on the TW2 method was at baseline 1.4±1.3cm in girls and 6.6±0.6cm in boys, at 1 year of GH treatment adult height was overestimated in girls 0.9±0.6cm in girls and underestimated 3.8±0.4 cm in boys, while at last bone age determination adult height was overestimated in mean by 1.1±0.9cm in girls and 4.5±0.5cm in boys.
Conclusions: Height prediction by bone age determinations at onset and in the first year of GH treatment underestimates adult height in prepubertal IGHD children. In contrast, in mean 6 years after onset of GH treatment height prediction based on bone ages overestimated adult height.