GnRH analogues(GnRHa) are used to treat central precocious puberty(CPP). However, in some patients, the GV decrease is so remarkable that it impairs predicted adult height(PAH); and there fore, the addition of growth hormone(GH) is suggested. We analysed the growth changes during two years and final adult height(FAH) in girls with idiopathic CPP treated with combined therapy, compared with those of girls treated with GnRHa alone.

For the analysis, we classified the patients, who was treated for longer than two years, into three groups depending on the initial PAH and combination of GH; PAH_L, treated with GnRHa and PAH less than midparental height(MPH) - 5 cm. PAH_H, treated with GnRHa and PAH greater than MPH - 5 cm. GnRHa＋GH, combined GH treatment, regardless of PAH before treatment. We analysed the GV and PAH change during the first two years and FAH.

In PAH_L, the PAH(SDS) at first year of therapy was significantly increased to 153.5±6.5 cm(-1.4±1.3) from 149.7±6.4 cm(-2.1±1.3) before treatment( P =0.004). In PAH_H, there was no significant increase in PAH during the two years of treatment. During the first year of combination of GH and GnRHa, GV and PAH increased significantly. We observed significant increases in FAH, comparing to the initial PAH in the PAH_L and GnRHa+GH groups. The height gains(FAH - initial PAH) were significantly higher in the PAH_L and GnRHa＋GH groups than that in the PAH_H group.

This study suggests the FAH and height gains are improved in patients, whose predicted adult height before treatment was shorter than those with higher predicted adult height, with the treatment of GnRHa alone or in combination with GH. GH could not improve the final adult height, but compensated the growth in patients whose growth velocity was decelerated by GnRHa alone.