A valuable improvement of adult height prediction methods in short normal children

Abstract

Objectives: The potential benefit of growth hormone (GH) administration to increase adult height of normal children of short stature might be blurred by the accuracy and the precision of the prediction methods used to estimate final height before onset of therapy. The aim of the present study was to evaluate three prediction methods: Bayley-Pinneau (BP), Roche-Wainer-Thissen (RWT) and Tanner-Whitehouse Mark II (TW2) and to improve their accuracy and precision by exploring their correlation with various parameters obtained in peripubertal children with poor predicted adult height.

Study design: Accuracy and precision of the prediction methods were evaluated retrospectively by comparing predicted adult heights estimated in 62 boys at 13.7 +/- 0.9 years and in 28 girls at 12.1 +/- 0.9 years of age, with their adult heights measured respectively at 20.7 +/- 2.6 years and 18.8 +/- 2.8 years.

Results: At the time of prediction, the height for chronological age was -2.07 +/- 0.68 standard deviation scores for boys and -2.15 +/- 0.6 years for girls. Measured adult heights were significantly lower than target heights (165.1 +/- 5.1 vs. 169.4 +/- 4.8 cm for boys; p < 0.001 and 153.1 +/- 3.9 vs. 156.3 +/- 5.0 cm for girls; p = 0.001). For boys, the BP method was the most accurate and also the most convenient with a predicted adult height of 164.7 +/- 5.0 cm and a small underestimation of 0.4 +/- 3.5 cm. For girls, the TW2 method was the most accurate with a predicted height of 152.4 +/- 3.7 cm with a little underestimation of 0.7 +/- 3.5 cm. There were no important differences between the precision of these methods. The use of a correction factor derived from the bone age delay at the time of prediction in boys and from the chronological age at the time of prediction in girls improved the accuracy of the predicted adult height.

Conclusions: The use of a factor correcting the accuracy of the BP method in boys and of the TW2 method in girls should be valuable in assessing the potential benefit of GH therapy to increase adult height in short normal children.