Are short boys with constitutional delay of growth and puberty candidates for rGH therapy according to FDA recommendations?

Background/Aims: According to FDA-approved guidelines, boys whose height predictions fall to 160 cm or less are considered for treatment with recombinant growth hormone (rGH). The aim of this study was to analyze the value of different height prediction methods by accurately identifying those boys with constitutional delay of growth and puberty (CDGP) in whom final height (FH) prognosis was poor (≤160 cm) and who might therefore be candidates for this treatment modality. Methods: In 69 boys with CDGP diagnosed at a mean age of 14.9 ±1.2 years, FH prediction was calculated by means of Bayley-Pinneau (BP), Roche-Wainer-Tissen (RWT), Tanner-Whitehouse II (TWII) and target height (TH) methods. At the age of 22.6 ± 3.5 years their height was remeasured and the accuracy of height prediction was analyzed. Results: In 6 men (8.7%) measured FH was ≤160 cm. Depending on the prediction method, different individual patients within the 14- to 16-year age range would have been candidates for rGH treatment. The BP method would have recruited 8 subjects of whom only 3 had FH ≤160 cm (sensitivity 50%, specificity 92%). The RWT and TW II methods identified only one recruit, and this patient did achieve FH ≤160 cm (sensitivity 17%, specificity 100%). None of the 8 subjects with FH ≤160 cm would have qualified for GH treatment using the TH method. In three boys none of the four methods predicted their final height ≤160 cm. Conclusion: Although some boys with CDGP may be considered the candidates for rGH treatment according to FDA recommendations, none of the available methods of prediction are sufficiently sensitive to reliably recruit 14- to 16-year-old boys whose final height will fall at or below 160 cm.