ESPE Abstracts

Background: Prediction of adult height is a standard procedure in pediatric endocrinology, but it is associated with considerable interrater variability.

Objective and hypotheses: To compare the new adult height prediction (PAH) method by automated bone age determination (BoneXpert™) with the conventional PAH method by Bayley Pinneau (BP) based on bone age determination according to Greulich & Pyle. Furthermore, to assess measures of bone health by bone health index (BHI) and pQCT.

Method: Height and near final height was determined in 82 patients (48 females) with chronic endocrinopathies at time of transition to adult care and with 10.45±2.12 years. In addition, pQCT and X-rays of the left hand were performed to obtain BHI and to assess bone ages according to Greulich and Pyle (manually by three experts) and by BoneXpert™. PAH was calculated using BP and BoneXpert™.

Results: The conventional and the automatic bone age determination revealed a mean difference of 0.23±0.74 years (P=0.0027), negligible if bone age was retarded or accelerated. The automated prediction of adult height by BoneXpert™ in females was 156.96±5.50 cm, in males PAH was 171.75±6.70 cm, the latter overestimated by 2.81±4 cm. When bone age was accelerated PAH by BoneXpert™ was slightly overestimated in females (2.7±2.9 cm) and in males (1±1.9 cm) compared to final height. If bone age was retarded there was a good accordance of PAH in females and males compared to final height. The mean BHI-SDS was reduced in comparison to the reference population (SDS −0.72±1.24). BHI correlated with bone mineral content (r²=0.5; P<0.0001), total bone mineral density (r²=0.35; P<0.0001), and muscle cross sectional area (r²=0.47; P<0.0001) determined by pQCT and grip force (r²=0.29; P<0.0001) determined by a dynamometer.

Conclusion: BoneXpert™ allows an objective and time-saving bone age assessment in children with chronic endocrinopathies and is suitable to predict valid PAH. BHI correlated with parameters of the ‘gold standard’ pQCT, but further studies are needed to validate BHI.