Final height after growth hormone therapy in short children: correlation with siblings' height

Sixteen prepubertal children (10 males, 6 females) were treated with growth hormone (GH) 0.75 U/kg/week for 4-5 years until final height was attained. Before initiation of GH therapy height was below 2 SDS for age and gender, growth velocity was <4.5 cm/year, bone age was more than 2 SD below the mean for age, and the GH response to provocative tests was more than 10 microg/l. The final height of 9 patients exceeded their predicted and target heights. The final height of the treated patients was highly correlated with their siblings' heights (r = 0.806, p < 0.001) and to a lesser degree with the target or the predicted height (r = 0.401, p = 0.124 and r = 0.465, p = 0.06, respectively). It is concluded that the secular trend should be taken into consideration when evaluating the success of GH therapy.