OBJECTIVETo develop a new method for predicting adult height (PAH) based on the theory of Bayley-Pinneau and to evaluate the feasibility of this method in predicting adult height of girls with idiopathic central precocious puberty (ICPP) who were treated with gonadotropin releasing hormone agonist (GnRHa).

METHOD(1) The new method for PAH, i.e. PAH = Height/percentage of adult height for bone age, was established according to the theory of Bayley-Pinneau and the data from the national growth survey of children in the nine cities of China in the year 2005. (2) Data from seventeen female patients with ICPP received GnRHa treatment and achieved final adult height (FAH) were collected. Before and during the treatment, PAH was calculated by the method of Bayley-Pinneau and the new method.

RESULTThe mean FAH(cm) of the 17 patients with ICPP was 159.81 ± 4.95. The PAH (cm), before and after treatment for 1, 2 and 3 years, were 156.53 ± 3.63, 157.71 ± 3.62, 158.60 ± 3.50, 161.46 ± 4.50 and 161.56 ± 3.77, 161.68 ± 3.44, 162.04 ± 4.42, 163.13 ± 2.36 respectively by using the new method (PAH-D) and Bayley-Pinneau method(PAH-BP). The mean value of (PAH-D-FAH) and (PAH-BP-FAH) were -1.96 cm and 1.48 cm. However, the 95% confidence interval was (-3.82 cm to -0.11 cm), (-1.60 cm to 4.55 cm) for (PAH-D-FAH) and (PAH-BP -FAH). There was no significant difference between the values obtained before and after treatment in terms of PAH by use of Bayley-Pinneau method. By the new method, however, the results showed that the PAH increased and improved further with prolonged treatment periods. And at the end of treatment, there was no significant difference between PAH and FAH. The correlation coefficient was 0.93. Regression analysis showed that the trend line was in parallel with baseline data.

CONCLUSIONThe new method we established could predict better the final heights of girls with CPP who were treated with GnRHa.