Growth Hormone Treatment in Short Children -Short-Term and Long-Term Effects on Growth

Short children with normal GH responses to arginine-insulin provocation testing and various amounts of spontaneously secreted GH over 24 hours participated in an ongoing study with GH, 0.1 IU/kg/day. A total of 40 prepubertal children have been treated for 1 year. Their mean height velocity increased from 4.6 to 7.5 cm/year. The children with the slowest pretreatment height velocity showed the best increment. An inverse relationship was found between the endogenous GH secretion and the increment in growth; 80% of the children had an endogenous GH secretion of less than 300 milliunits/litre/24 hours, estimated as area under the curve above the calculated baseline. They all showed an increment in height above 2 cm. The remaining 20% all had an endogenous GH secretion of more than 300 milliunits/litre/24 hours, estimated as area under the curve above the calculated baseline, Twenty-four of the children were prepubertal for the following 4 years, and their GH therapy continued. Their Deight velocity changed from 4.2 cm/year before therapy to 8.1,6.7,6.0 and 4.9 cm/year for the 1st, 2nd, 3rd and 4th years on treatment. Many of them have passed their expected final height, but have still not stopped growing. Those children who were in early puberty when GH treatment started went into a rapid growth spurt and have now stopped growing. They have all reached but not improved their expected final height. In 15 of the children GH treatment was stopped after 1-3 years. Their mean height velocity for the first post-treatment year was 5.1 cm/year; thus, for the group as a whole no'catch down'was observed. Of the 15 children, only 4 decreased in height velocity despite increasing age. Further studies on the long-term results of GH treatment in larger groups of short children are needed to verify the findings in this study.