Management of Growth Hormone Deficiency Through Puberty

ABSTRACT. As a model of the growth hormone (GH) dependence of growth in prepuberty and puberty, the growth of 182 children (93 boys, 89 girls) who survived in first remission for treatment of acute lymphoblastic leukaemia was examined. Chemotherapy regimens, including intrathecal methotrexate, were similar in all patients, but CNS treatment differed, in that one group received 2400 cGy cranial irradiation, while the other received 1800 cGy. There was a significant decrease in height SDS during prepuberty, which was equivalent in both sexes, whereas there was a much greater decrease in pubertal growth in girls than in boys. Girls treated with the lower dose regimen of cranial irradiation had their onset of pubertal maturation significantly advanced, to a mean of 9.9 years ( p < 0.001). Previous studies have indicated that the duration of puberty is shortened by GH treatment in patients with idiopathic multiple pituitary hormone deficiency or isolated GH deficiency (GHD). To determine whether an increase in the dose of GH administered during the adolescent growth spurt would improve final height, a prospective randomized trial was performed in 32 children (25 boys, 7 girls) with isolated GHD treated with a GH dose regimen of 15 IU/m²/week as daily s.c. injections. At the onset of the pubertal growth spurt, the patients were randomized either to an unchanged dose or to 30 IU/m²/week. There was no significant change in height velocity with the doubled dose of GH, but there was a trend in the advancement of pubertal maturation which was considered to be dose related. It is suggested that these findings are of relevance to the treatment of GHD in puberty, especially in girls with early or precocious puberty occurring as a consequence of low-dose cranial irradiation. It is concluded that optimum final heights may not be achieved in these patients without the therapeutic manipulation of the onset and/or duration of puberty.     

Growth and Growth Hormone Therapy in Hypochondroplasia

ABSTRACT. The growth of 84 patients with hypochondroplasia (56 male, 28 female) was studied. A wide spectrum of severity was found from quite severe short limbed dwarfism to short apparently normal prepubertal children who manifested disproportion only at puberty when growth failed. The onset of puberty was at the normal time but the pubertal growth spurt appeared not to materialize and it is this lack which resulted in severely compromised adult heights of 145-165 cm in boys and 133–151 cm in girls. Twenty (12 M, 8 F) hypochondroplastic children aged between 4.3 and 12.8 years were recruited to a study of the effects of biosynthetic growth hormone. All had normal growth hormone responses (> 15 mU/I) to a pharmacological test of growth hormone secretion. Biosynthetic growth hormone in doses between 12-32 u/m²/week produced a significant acceleration in height velocity standard deviation score (SDS) for chronological age (CA) from a pretreatment mean of - 1.66 (SD 1.36) to + 1.62 (SD 1.52) ( p < 0.001). Significant increases were also observed in the height SDS for bone age (BA), sitting height (SH) SDS and subischial leg length (SILL) SDS. A longer period will be required to assess the effect of treatment on adult height prognosis.     

Growth and Growth Hormone Secretion in Children Following Treatment of Brain Tumours with Radiotherapy

ABSTRACT. We have studied the growth of 144 children after treatment of brain tumours distant from the hypothalamo-pituitary axis. All had cranial irradiation and 87 spinal irradiation. In 56 patients observed without intervention for 3 years, height SDS in the cranial (CR) group (n= 20) declined from 0.02 to -0.44 and in the craniospinal (CS) group (n= 36) from -0.28 to - 1.11. Failure of spinal growth had a marked effect in the CS group. The onset of puberty was slightly but not significantly advanced; median ages at onset of puberty were 10.3 years in girls and 12.1 years in boys.
Of the total group 86.4% had clinical and biochemical evidence of growth hormone insufficiency. Fifty-two children, 33 (28 CS; 5 CR) of whom were prepubertal, received biosynthetic human growth hormone, in a dose of 15 mU/m²/week by daily injection for a period of one year. Height velocity SDS increased significantly in both groups from -2.74 to + 1.90 (CS) and from -1.0 to +4.26 (CR). Spinal response to GH treatment was restricted in the craniospinal group.     

Noonan's Syndrome: Abnormalities of the Growth Hormone/IGF-I Axis and the Response to Treatment with Human Biosynthetic Growth Hormone

ABSTRACT. Auxological and endocrine data from 6 children (3 male, 3 female) aged 8.5–12.8 years with Noonan's syndrome and the results of treatment with human biosynthetic growth hormone (hGH) are presented. All the children were short (Ht SDS -3.5 to -2.3) and height velocity SDS ranged between -1.76 and +0.03. The maximum plasma growth hormone (GH) response to standard provocation tests ranged from 17 to 52 mU/l, yet, plasma insulin-like growth factor I (IGF-I) concentrations were low or low normal. Overnight GH secretory profiles were normal in all but 2 children who had disordered pulsatility with high trough concentrations. In 5 children who have completed one year of hGH therapy mean height velocity increased from 4.8 to 7.4 cm/year and the height velocity SDS ranged from +0.2 to +3.75. This improvement was associated with an increase in plasma IGF-I in three subjects. These results suggest that a defect of the GH/IGF-I axis may be present in some children with Noonan's syndrome and hGH therapy may have a role in the management of the short stature in these children.     

Growth Hormone Treatment in Non-Growth Hormone-Deficient Children: Effects of Stopping Treatment

ABSTRACT. Overnight physiological growth hormone (GH) secretion was evaluated in 95 short, prepubertal children (73 boys, 22 girls). All the children were below the 3rd centile for height and achieved CH levels greater than 15 mU/1 following pharmacological stimulation. The mean average GH level was 7.1 mU/l and the mean sum of pulse amplitudes 80.4 mU/l. No relationship was found between age, height or height velocity and any of the parameters of GH secretion. The group was randomized to receive placebo, GH or remain under observation for the first 6 months and then all patients received GH treatment for a further 6 months. Those treated with GH, 0.27 IU/kg (0.1 mg/kg) three times weekly, in the first phase. demonstrated a mean increase in height velocity SDS of 3.24. There was no difference in growth response between the placebo or observation groups. In the second 6-month period. all children received GH according to the same dose regimen: they were then observed for a further 6 months following its discontinuation. In the 6 months following withdrawal of GH, all groups showed a significant fall in height velocity SDS, which returned to pretreatment levels, without demonstrating'catch-down'growth. Repeat sampling of overnight GH secretion within 3 days of discontinuing GH showed normal secretory patterns with a small reduction in mean peak amplitude. These results suggest that short children without classic GH insufficiency respond well to exogenous GH in the short term and return to pretreatment height velocities afterwards. Consequently, it may be possible to increase final adult height in such children by GH treatment.     

Predictive Criteria for Successful Growth Promotion in Growth Hormone Therapy of Short Stature: A Comparison between Common Endocrine Parameters and Knemometry

ABSTRACT. Due to increased availability of growth hormone (GH) for the treatment of short stature, its use has been proposed for a number of conditions besides classic GH deficiency. We have studied growth response during a one year treatment period with 14 IU/m²/week of GH in a heterogenous group of 24 short children with various conditions associated with short stature (SDS for body height ranging between −2.2 and −4.4). Thirteen children could be classified as "responders" with growth rate increments of 2 cm/yr or more above pretreat-ment growth rates, and 11 children as "non-responders". The children were measured regularly both by stadiometry and knemometry at weekly intervals. GH stimulation by insulin, arginine and spontaneous overnight secretion of GH, and SM-C generation were evaluated in the children and found to be of no predictive value for the individual responsiveness to GH administration except in one boy with classic GH deficiency. However, serial measurements of the lower leg length provided useful information for individual predictions in 21 out of the 24 children as early as 10 weeks after the start of the GH treatment.     

Synchronization of Growth Hormone Therapy

Based on the hypothesis of periodical refractoriness of the growing tissue to exogenous administration of GH, an experimental approach is presented in which the dosage of GH was adjusted to the natural occurrence of periodical changes of the lower leg growth velocity in five children with short stature. Two 6-month periods were compared, during which the children received an identical cumulative dose of GH of 224 IU/m². During the first period, the children received a constant GH dose of 14 IU/m²/week by daily subcutaneous injection, whereas a low/high dose alternation was administered at approximately 3-week intervals synchronously with the occurrence of mini growth spurts during the second 6-month period. In all the children, mean linear growth of the lower leg accelerated during the period of synchronization by 595% compared to the previous growth rate during constant GH administration.     

Investigation of Growth Hormone Secretion in Patients with Intrauterine Growth Retardation

Rochiccioli, P., Tauher, M., Moisan, V. and Pienkowski C. (Department of Paediatrics, CHU Rangneil, Toulonse Cedex, France). Investigations of growth hormone secretion in patients with intrauterine growth retardation. Acta Paediatr Scand [Suppl] 349: 42, 1989.
Growth hormone (GH) deficiencies have rarely been reported in intrauterine growth retardation (IUGR). This study has investigated GH secretion using GH provocation tests, 24-hour GH secretory profiles, and insulin-like growth factor I (IGF-I) measurements in 24 children with intrauterine growth retardation. The criteria for diagnosis were a birth length and weight below the 10th percentile for gestational age. The average age at investigation was 5.5 years, and the average growth retardation was -3.3 SD. Twenty children had shown catch-up growth between the ages of 6 months and 3 years, followed by varying decreases in growth velocity. Studies of GH secretion demonstrated GH deficiency in 16 patients, with neurosecretory dysfunction in six. Treatment with pituitary GH in nine children increased mean growth velocity from 3.5 cm/year to 7 cm/year. GH therapy should thus be effective in improving the height prognosis of children with intrauterine growth retardation.     

Growth Response in Prepubertal Children with Idiopathic Growth Hormone Deficiency during the First Year of Treatment with Human Growth Hormone. Analysis of the Kabi International Growth Study.

ABSTRACT. In order that children with growth hormone deficiency (GHD) reach the goal of normal adult stature, treatment modalities need to be optimized. From the large database of patients enrolled in the Kabi International Growth Study (KIGS), 257 prepubertal patients with idiopathic GHD undergoing their first year of growth hormone (GH) substitution therapy were selected. A multiple regression analysis was performed to determine both auxiological factors characterizing the patients and the factors related to the chosen treatment modalities which are of significance for the observed magnitude of the growth response. Due to the structure of the data, pretreatment height velocity and bone age-derived auxiological data were not considered. It was observed that the magnitude of the growth response was inversely correlated with chronological age and relative height (HT SDS) at the start of GH treatment but was positively correlated with mid-parental height. The growth response was also positively correlated with the GH dose (IU/kg/week) and the frequency of GH injections per week. A regression equation using these five parameters was derived, allowing the growth response of these patients to be predicted. The extension of this analytical approach in the future will allow the treatment of patients with GHD to be tailored to individual requirements.     

Influence of growth hormone treatment on pubertal timing and pubertal growth in children with idiopathic short stature. Dutch Growth Hormone Working Group

We studied the influence of recombinant human growth hormone (rhGH) on pubertal timing and pubertal growth in children with idiopathic short stature (ISS), and evaluated whether this was different between children with and without intra-uterine growth retardation (IUGR). Twenty-six (18 M, 6 IUGR; 'treated') subjects were treated with rhGH (6-7 days/week, dosage: 14-28 IU/m2 per week [i.e. 0.2-0.3 mg/kg per week]). Fifty-eight subjects (31 M, 9 IUGR; 'controls') were not treated. All subjects attained final height. Prepubertal height gain was significantly larger in the treated children compared to control children (M: 0.66 SDS, 95% confidence interval [CI] 0.41 to 0.92; F. 0.92 SDS, CI 0.58 to 1.26). Pubertal height gain, peak height velocity and duration of puberty were similar for the treated and control subjects. rhGH advanced the age at peak height velocity by 0.7 years (CI 0.3 to 1.0) in boys, and the age at onset of puberty by 1.1 years (CI 0.3 to 1.9) in girls. The gain in final height was 2-3 cm. Age and height SDS at start were the most important predictors for pubertal height gain, total height gain and final height in a multivariate regression analysis. Total height gain of treated subjects with IUGR was less than that of treated subjects without IUGR. In conclusion, rhGH did not affect pubertal growth in children with ISS, and slightly improved their final height. rhGH treatment should be started early to improve height as much as possible before the onset of puberty.     

Growth Hormone Secretion and Growth Hormone Treatment in Children with Intrauterine Growth Retardation

Albertsson-Wikland, K. (Departments of Paediatrics II and Physiology, University of Gothenburg, Gothenburg, Sweden). Growth hormone secretion and growth hormone treatment in children with intrauterine growth retardation. Acta Paediatr Scand [Suppl] 349: 35, 1989.
Few children with intrauterine growth retardation (IUGR) fail to show catch-up growth during the first year of life. There may he many reasons for this, ranging from disturbances of hormone production to hormonal unresponsiveness of target cells. This report presents preliminary data on growth hormone (GH) secretion and responses to GH treatment in 16 children with IUGR and poor catch-up growth, six of whom had Silver-Russell stigmata. GH secretion was assessed by measurement of the GH response to an arginine-insulin test and determination of spontaneous GH secretion over 24 hours. GH production was heterogeneous hut, more often than expected, children showed both a low response to GH provocation and low spontaneous secretion of GH. Five out of six of the children with Silver-Russell syndrome and seven out of 10 of the children with non-Silver-Russell IUGR gained more than 2 cm in height during 1 year of treatment with GH at a dose of 0.1 IU/kg/day. These results clearly demonstrate that some children with IUGR and poor catch-up growth secrete insufficient amounts of GH, and that many of these very short children show an improvement in growth rate during treatment with physiological doses of GH.     

Long-Term Results with a Slow-Release Gonadotrophin-Releasing Hormone Agonist in Central Precocious Puberty

ABSTRACT. As part of an ongoing international multicentre study, 19 children (14 girls, 5 boys) with central precocious puberty (CPP) were treated with a slow-release gonadotrophin-releasing hormone (GnRH) agonist, triptorelin, for 4 years. After 3 years of treatment, height velocity stabilized at 4.0 cm/year. Predicted adult height (mean ± SD) increased from 158.9 ± 6.8 to 164.9 ± 6.6 cm in girls (n = 14, p < 0.01), and from 174.4 ± 18.5 to 184.3 ± 17.1 cm in boys (n = 4, p < 0.05). In 12 additional girls who had started the multicentre study but discontinued triptorelin treatment after 2.2 ± 0.5 years, menses started 9.8 ± 3.7 months after cessation of treatment in all but one patient. Height velocity increased over the first 6 months after discontinuation of treatment, from 3.6 ± 0.1 to 5.4 ± 2.5 cm/year, and remained higher than pretreatment values in the second 6 months, but decreased subsequently. Bone maturation increased, and no significant improvement in predicted adult height was observed. For auxological reasons, therefore, it may be advisable to continue triptorelin treatment for as long as possible. Concomitant growth hormone (GH) therapy was initiated in three girls with CPP with height velocities of 3.2–3.6 cm/year after 3 years of treatment with triptorelin and predicted adult heights of less than the third centile for Dutch girls. Prior to the administration of GH, all patients had subnormal 24-hour GH profiles and GH responses to arginine provocation. GH treatment increased height velocity markedly in all girls, and improved predicted adult height. It is concluded that triptorelin therapy improves predicted adult height. In children with CPP and genetic short stature, with a markedly decreased height velocity during triptorelin therapy, concomitant administration of a GnRH agonist and GH may have advantages. Further extensive studies are required.     

No Improvement of Adult Height in Non-growth Hormone (GH) Deficient Short Children with GH Treatment

It is still in doubt whether the standard-dose growth hormone (GH) used in Japan (0.5 IU/kg/week, 0.167 mg/kg/week) for growth hormone deficiency is effective for achieving significant adult height improvement in non-growth hormone deficient (non-GHD) short children. We compared the growth of GH-treated non-GHD short children with that of untreated short children to examine the effect of standard-dose GH treatment on non-GHD short children. GH treatment with recombinant human growth hormone (rhGH) was started before the age of 11 yr in 64 boys and 76 girls with non-GHD short stature registered at the Foundation for Growth Science who have now reached their adult height. In 119 untreated boys and 127 untreated girls whose height standard deviation score (SDS) was below –2 SD at the age of 6 yr, height growth was followed until 17 yr. Height SDS was significantly lower before GH treatment in the GH-treated group than at the age of 6 yr in the untreated group, in both sexes. Adult height and adult height SDS were significantly greater in the untreated group than in the GH-treated group, in both sexes, although the change in height SDS did not differ significantly. Height SDS was significantly lower before GH treatment in the GH-treated group than at the age of 6 yr in the untreated group, so 57 boys and 57 girls whose height SDS at the age of 6 yr in the untreated group closely matched the height SDS before GH treatment in the GH-treated group were chosen for comparison. Height SDS did not differ significantly between the GH-treated group before GH treatment and the untreated group at the age of 6 yr, nor were there differences between these subgroups in adult height, adult height SDS, or height SDS change, in either sex. The effect of GH treatment is reported to be dose-dependent and doses over 0.23 mg/kg/week are reported to be necessary to improve adult height in non-GHD short children. Currently, the GH dose is fixed at 0.175 mg/kg/week in Japan, and we expected to find, and indeed concluded, that ordinary GH treatment in Japanese, non-GHD short children does not improve adult height.     

Growth Response in Prepubertal Children with Idiopathic Growth Hormone Deficiency During the First Two Years of Treatment with Human Growth Hormone. Analysis of the Kabi Pharmacia International Growth Study

From the large database of patients enrolled in the Kabi Pharmacia International Growth Study (KIGS), 289 prepubertal patients with idiopathic growth hormone deficiency (GHD), treated for 2 years with growth hormone (GH) substitution therapy, were selected. A multiple regression analysis was performed to determine both the auxological factors characterizing the patients at the beginning of the first and second years on GH therapy and the respective treatment modalities relevant to the magnitude of the growth response. It was observed that during the first year on GH therapy the magnitude of the growth response was negatively correlated with chronological age and height SDS, and positively correlated with target height SDS, GH dose (IU/kg/week) and frequency of GH injections. During the second year the growth response was negatively correlated with chronological age and the first-year GH dose (IU/kg/week), and positively correlated with height velocity during the first year, GH dose (second year), and injection frequency (second year). The data suggest that the forces of'catch-up'- auxologically entrenched within the distance between target height SDS and height SDS - no longer prevail during the second year of GH therapy. The inverse influence of the first-year GH dose in the two yearly phases of growth suggests that optimizing GH treatment must be attempted by analysing growth in response to GH over longer periods of time and considering that the growth process is influenced by interactive factors.     

Predicting and Monitoring of Growth in Children with Short Stature during the First Year of Growth Hormone Treatment

ABSTRACT. Fifteen prepubertal short stature children (10 girls, 5 boys), mean age 9.6 years (range 5.2–12.7 years), with normal response to growth hormone stimulation tests (group A) or partial growth hormone deficiency (GHD) of idiopathic nature (group B) were included in a controlled longitudinal study for evaluation of predictive parameters for the long-term growth response after administration of biosynthetic human growth hormone (B-hGH). The average knee–heel length velocity for the first 3 months was significantly correlated to total body height velocity during the following 9 months ( p <0.0008). By contrast, this association could not be found for height velocity during the same period. The increase in serum values of alkaline phosphatase and insulin-like growth factor I (IGF-1) during the first month of treatment was not significantly correlated to height velocity during the first year. During one year of treatment with B-hGH the mean height velocity for groups A and B increased from 4.4 cm/year (range 2.5–6.5) to 7.6 cm/year (range 4.7–10.6). Bone age advanced by 1.08 t0.60 per chronological year. The ratio between total height and knee-heel length prior to treatment was 3.34 ± 0.10 and after one year 3.33 ± 0.10, suggesting a proportional linear growth. An inverse relationship was observed between the ratio and chronological age. In conclusion, early knee–heel measurement may be a useful non-invasive predictor of long-term linear growth in children during treatment with growth hormone, and the ratio of total height to lower leg length may be of importance in detecting dysproportional growth.     

A Controlled Trial of Methionyl Growth Hormone Therapy in Prepubertal Children with Short Stature, Subnormal Growth Rate and Normal Growth Hormone Response to Secretagogues

ABSTRACT. Thirty short and slowly growing children with normal plasma growth hormone (GH) responses to standard provocation tests were randomly assigned to either a group ( n = 20) undergoing treatment with methionyl GH (somatrem), 2IU per m² body surface s.c. daily, or a control group ( n = 10). Twelve out of 18 children who completed the first year of treatment showed a height velocity increment of more than 2 cm/year. The mean (SD) growth velocity of the treatment group increased by 3.0 (1.9) cm/year over the first year, compared with -0.2 (0.7) cm/year in the control group. Neither parameters of endogenous GH secretion nor plasma IGF-I levels showed a significant correlation with the growth response. Of the auxological variables studied, pre-treatment growth velocity ( r = 0.8) and the short-term height velocity increment ( r = 0.7–0.9) showed significant correlations with the growth response in the first year of treatment. Somatrem therapy was without side effects, except in one child who developed anti-GH antibodies in combination with a poor growth response.     

Growth Response to Human Growth Hormone Treatment in Children with Partial and Total Growth Hormone Deficiency

ABSTRACT. The growth response during the first and second years of human growth hormone (hGH) treatment was studied in 14 prepubertal children with so-called "partial" GH deficiency (peak GH between 8 and 15 mU/1) and compared to 28 prepubertal children with "total" GH deficiency (peak GH less than 8 mU/1). There was no difference in growth acceleration between children with partial and total GH deficiency, when initial covariables were taken into account. In a stepwise multiple regression analysis initial stature, pre-treatment growth velocity and skinfold thickness were shown to be most related to growth response, but after exclusion of 3 children with a genetic form of total GH deficiency and partial TSH deficiency this relationship was lost. GH levels during provocation tests and auxological criteria have a poor predictive value for growth response to hGH therapy.     

Growth hormone treatment of idiopathic short stature: analysis of the database from KIGS, the Kabi Pharmacia International Growth Study

Within the Kabi Pharmacia International Growth Study (KIGS) database, there is information on 1017 (700 male/317 female) patients with idiopathic short stature (ISS). These patients were started on recombinant human growth hormone (GH) at a median age of 10.8 years, a bone age of -1.8 SDS, a height of -2.6 SDS and a predicted adult height (PAH) (Bailey–Pinneau method) of -2.5 SDS. The median dose of GH was 0.6 IU/kg body weight/week and the frequency of injections was six/week. According to the relationship with target height the patients were classified into'familial short stature (FSS)'(height SDS > target height SDS - 1.28) and into'non-FSS'(height SDS < target height SDS - 1.28). During the first year of GH treatment there was an overall increment in the median height velocity from 4.4 to 7.4 cm/year. Over 3 years of GH treatment, cross-sectional analysis demonstrated an overall increment in median PAH of 1.2 SDS. There was a positive correlation between gain in PAH and the GH dose (n = 202, r = 0.18, p < 0.01) during the first year. Longitudinal analysis in 84 patients showed an overall increment of PAH of 0.7 SDS over 2 years of treatment. When applying the KIGS first-year prediction model for patients with idiopathic GH deficiency on cohorts of prepubertal children with FSS and non-FSS, a lower responsiveness to GH in the non-FSS group was observed. It is concluded that higher than substitutive doses of GH are required for the long-term improvement of growth in ISS.     

Three-year data from a comparative study with recombinant human growth hormone in the treatment of short stature in young children with intrauterine growth retardation

Growth acceleration and bone maturation were studied for 3 y in 69 children with severe short stature and a history of intrauterine growth retardation (IUGR), to determine the effect of treatment with recombinant human growth hormone (r-hGH). The patients were enrolled in an open, multicentre trial and were randomly allocated to either the treated group (Group 1) or the control group (Group 2). The children in Group 1 were treated daily with 0.2 IU/kg/body weight (0.067 mg/kg) s.c, during 3 y and the children in Group 2 started the study with a 1-y observation period followed by a 3-y treatment period. At birth, their mean weight standard deviation score (SDS) was -2.5 and their mean length SDS -3.5. At baseline, the patients were prepubertal, non-GHdeficient, with no known dysmorphic features. Mean age was 4.5 y, bone age was 3.3 y, height SDS was -3.4, height velocity (HV) SDS was -1.6, and body mass index SDS was -1.4. After 1 y of treatment, linear HV in Group 1 increased in comparison with the pre-treatment period (from 5.7 ± 2.0 to 10.1 ± 1.7cm/y; p < 0:001)and with the firstyear of observation in Group2( p < 0:001). Increased HV was sustained during the second and third year of treatment and was significantly higher than at baseline. A similar growth pattern was seen during the 3y of GH treatment in Group 2. Mean height SDS for chronological age increased by 2.0 ± 0.7 in the two groups after 3 y of treatment. HV after 1 y of treatment was negatively correlated with growth velocity at baseline. Bone age remained retarded but increased with a mean of almost 4 y after 3y of treatment in both groups. Even at a dose that is three times the replacement dose treatment with r-hGH was well tolerated. From these results, we conclude that r-hGH treatment over 3 y can induce sustained catch-up growth in young children with severe short stature and a history of IUGR. Long-term studies are needed to assess ultimate effects on final height.     

Prediction of the growth response in children with various growth disorders treated with growth hormone: analyses of data from the Kabi Pharmacia International Growth Study

Analyses to predict the growth response to recombinant human growth hormone (GH) in prepubertal children during the first year of treatment were performed on data from 472 patients with idiopathic GH deficiency (IGHD), 202 children with Turner's syndrome, 327 children with idiopathic short stature (ISS) and 135 children with intrauterine growth retardation (IUGR). In IGHD, 56% of the variability of the response could be predicted from a model based on six variables. These variables could be ranked in order of importance as follows: target height SDS minus height SDS, chronological age, frequency of GH injections, dose of GH, weight-for-height index, and birth weight SDS. When the model for IGHD was applied to Turner's syndrome, ISS and IUGR, there was a high degree of similarity between the predicted and achieved growth response in ISS and IUGR. However, an uneven distribution within the plot of Studentized residuals in ISS and IUGR suggested heterogeneity within these populations. Prediction of growth in Turner's syndrome was greatly exaggerated by the model for IGHD, suggesting a different pathogenesis as the basis of the growth disorder. Specific prediction models were therefore developed for Turner's syndrome, ISS and IUGR. In all three disorders, the dose of GH was found to be the most important predictor, suggesting that, in contrast to IGHD, first-year growth is governed less by the difference between height and the presumed genetically determined target height. Again, in contrast to IGHD, this suggests that catch-up phenomena are not involved. As the predictability of the variation in growth response in Turner's syndrome, ISS and IUGR did not exceed 32% (for ISS), the search for new predictors should continue in these disorders.