Effects of 3 years of growth hormone therapy in short normal children

Height Gain and Safety Outcomes in Growth Hormone-Treated Children with Idiopathic Short Stature: Experience from a Prospective Observational Study

BACKGROUND/OBJECTIVES

Growth hormone (GH) treatment of idiopathic short stature (ISS) received US Food and Drug Administration approval in 2003. We assessed height gain and safety in 2,450 children with ISS treated with GH in US clinical practice.

METHODS

Short-term height gain, near-adult height (NAH), and safety outcomes were investigated using Genetics and Neuroendocrinology of Short Stature International Study data.

RESULTS

Compared to children with isolated idiopathic GH deficiency (IGHD), those with ISS were shorter at baseline but had similar age and GH dose. Mean ± SD height SD score (SDS) increase was similar for ISS and IGHD, with 0.6 ± 0.3 (first), 0.4 ± 0.3 (second), 0.3 ± 0.3 (third), and 0.1 ± 0.3 (fourth year) for ISS. Girls with ISS (27% of subjects) were younger and shorter than boys but had similar height gain over time. At NAH in the ISS group (n = 467), mean ± SD age, GH duration, and height SDS were 17.3 ± 2.3 years, 4.6 ± 2.7 years, and -1.2 ± 0.9, respectively. Height gain from baseline was 1.1 ± 1.0 SDS and was greater for boys than girls (1.2 ± 1.0 vs. 0.9 ± 0.9), but boys were treated longer (5.1 ± 2.8 vs. 3.6 ± 2.5 years). Adverse events were reported for 24% with ISS versus 20% with IGHD - most were common childhood conditions or previously reported in GH-treated patients.

CONCLUSIONS

GH-treated children with ISS achieved substantial height gain, similar to patients with IGHD. Fewer GH-treated girls were enrolled than boys, but with similar height SDS gain over time. No ISS-specific safety issues were identified. Thus, GH treatment of ISS appears to have a safety/effectiveness profile similar to that of IGHD.

Growth hormone (GH) treatment to final height in children with idiopathic short stature: evidence for a dose effect

OBJECTIVES

To investigate in an open-label randomized study, the effect of two doses of growth hormone (GH) on final height and height velocity during the first 2 years of treatment of children with idiopathic short stature (mean baseline height standard deviation score [SDS] -3.2).

STUDY DESIGN

Patients were treated with GH at 0.24 mg/kg/week, 0.24 mg/kg/week for the first year and at 0.37 mg/kg/week thereafter (0.24-->0.37), or 0.37 mg/kg/week. Final height was evaluated in 50 patients at study completion (mean treatment duration, 6.5 years).

RESULTS

Patients who received 0.37 mg/kg/week (n = 72) experienced a significantly greater increase in height velocity than those who received 0.24 mg/kg/week (n = 70) (treatment difference = 0.8 cm/year; P = .003) or 0.24-->0.37 mg/kg/week (n = 67) (treatment difference = 0.9 cm/year; P = .001). For the 50 patients for whom final height measurements were available, mean height SDS increased by 1.55, 1.52, and 1.85 SDS, respectively, for the three dose groups. For the primary comparison between the 0.37 mg/kg/week and 0.24 mg/kg/week dose groups, the mean treatment difference (adjusted for differences in baseline predicted height SDS) was 0.57 SDS (3.6 cm; P = .025). Mean overall height gains (final height minus baseline predicted height) were 7.2 cm and 5.4 cm for the 0.37 mg/kg/week and 0.24 mg/kg/week dose groups, respectively, without dose effects on safety parameters. Final height measurements were within the normal adult height range for 94% of patients randomized to 0.37 mg/kg/week who continued to final height.

CONCLUSION

GH treatment dose-dependently increases height velocity and final height in children with idiopathic short stature.

Growth hormone treatment in children: review of safety and efficacy

Since the advent of growth hormone (GH), the pediatric applications of GH therapy have expanded. Children with a wide variety of growth disorders have received GH treatment. The therapeutic effects and safety profile of GH in a number of pediatric conditions are reviewed, including GH deficiency (GHD), Turner syndrome, chronic renal failure, children born small for gestational age, Prader-Willi syndrome, juvenile chronic arthritis, and cystic fibrosis. GH therapy has been clearly shown to improve height velocity during childhood in a variety of pediatric conditions in which growth is compromised. There is now data that confirms GH treatment also improves final height in a number of diagnostic subgroups. Early initiation and individualization of GH treatment has the potential to normalize childhood growth in children with idiopathic GHD and enable them to achieve their genetic target height in a cost-effective manner. In children in whom GHD is not the main factor compromising growth, supra-physiological doses of GH have been shown to increase height velocity during childhood and final height. The development of predictive models for these conditions may allow further improvements in height outcome while maintaining an acceptable safety profile. Survivors of childhood malignancy, particularly those who have had craniospinal irradiation, represent a particularly challenging group. They appear to be less responsive to GH than children with idiopathic GHD and have a tendency to enter puberty at an earlier age. Both of these factors have a negative impact on their final height. Strategies that combine GH treatment with suppression of puberty using a gonadotropin releasing hormone analog may result in improved height outcomes. When children with GHD are treated with standard doses of GH there is a strong safety record. Adverse events during GH therapy are uncommon and often not drug related. Continued surveillance into adult life is crucial however, particularly in children receiving supra-physiological doses of GH or whose underlying condition increases their risk of adverse effects.

The effect of 3 years of recombinant growth hormone therapy on glucose metabolism in short Chinese children with beta-thalassemia major

Growth retardation and diabetes mellitus are common in children and adolescents with beta-thalassemia major despite hypertransfusion regimen and iron chelation therapy. The purpose of this study was to investigate the effects of growth hormone (GH) treatment on glucose metabolism in children with beta-thalassemia major. GH therapy for 3 years improved the height SD scores of eight short prepubertal Chinese children with beta-thalassemia major from -2.15 +/- 0.90 to -1.14 +/- 0.78 (paired t-test, p = 0.01) without excessive advancement in bone age (ABA/CA = 0.95 +/- 0.27). There was no deleterious effect on glucose metabolism with no change in fasting blood sugar, serum fructosamine, fasting and stimulated insulin to intravenous glucose infusion (sum of 1+3 min insulin, In 1+3'; incremental insulin 0-10 min area above fasting concentrations, deltaInAUC0-10'; ratio of incremental 0-10 min insulin area above fasting concentrations over glucose area above fasting concentrations, delta0-10'AUCIn/G; ratio of incremental 0-10 min insulin over peak glucose above basal 0-10 min, delta0-10'InAUC/deltaGPeak), and glucose disappearance coefficient (Kg). Short term GH therapy improves the height of children with beta-thalassemia major but the effect of treatment on final height still needs to be determined.

Effect of growth hormone treatment on adult height of children with idiopathic short stature. Genentech Collaborative Group

BACKGROUND

Short-term administration of growth hormone to children with idiopathic short stature results in increases in growth rate and standard-deviation scores for height. However, the effect of long-term growth hormone therapy on adult height in these children is unknown.

METHODS

We studied 121 children with idiopathic short stature, all of whom had an initial height below the third percentile, low growth rates, and maximal stimulated serum concentrations of growth hormone of at least 10 microg per liter. The children were treated with growth hormone (0.3 mg per kilogram of body weight per week) for 2 to 10 years. Eighty of these children have reached adult height, with a bone age of at least 16 years in the boys and at least 14 years in the girls, and pubertal stage 4 or 5. The difference between the predicted adult height before treatment and achieved adult height was compared with the corresponding difference in three untreated normal or short-statured control groups.

RESULTS

In the 80 children who have reached adult height, growth hormone treatment increased the mean standard-deviation score for height (number of standard deviations from the mean height for chronologic age) from -2.7 to -1.4. The mean (+/-SD) difference between predicted adult height before treatment and achieved adult height was +5.0+/-5.1 cm for boys and +5.9+/-5.2 cm for girls. The difference between predicted and achieved adult height among treated boys was 9.2 cm greater than the corresponding difference among untreated boys with initial standard-deviation scores of less than -2, and the difference among treated girls was 5.7 cm greater than the difference among untreated girls.

CONCLUSION

Long-term administration of growth hormone to children with idiopathic short stature can increase adult height to a level above the predicted adult height and above the adult height of untreated historical control children.

Final height after combined growth hormone and gonadotrophin-releasing hormone analogue therapy in short healthy children entering into normally timed puberty

OBJECTIVE

Combined gonadotrophin-releasing hormone analogue and recombinant human growth hormone therapy has been used in an attempt to improve the final height of short non-GH deficient adolescents with normally timed puberty; its use, however, is still controversial as only short-term studies in a very limited number of patients have been undertaken, with either improvement in height prognosis or no beneficial effect on predicted growth. We have treated a group of extremely short healthy children with very low predicted adult heights entering into normally timed puberty with combined therapy, in order to determine whether we could improve their final height above their pretreatment predicted adult height.

PATIENTS

We treated 10 healthy adolescent short children (7 girls and 3 boys) simultaneously for 30.0 +/- 5.2 months with the GnRH analogue leuprolide acetate (0.3 mg/kg im every 28 days) and with rhGH (0.1 U/kg/day, sc, 6 days a week). The mean chronological age of our patients was 11.8 +/- 1.3 years, with a mean bone age of 11.2 +/- 0.9 years, height of 128.9 +/- 7.5 cm (-2.4 +/- 0.4 SD below the mean) and a predicted adult height of 150.7 +/- 9.8 cm; they were all in Tanner stage II-III of puberty. Ten healthy short children (7 girls and 3 boys) in the early stages of puberty with a mean chronological age of 11.4 +/- 1.0 years, a mean bone age of 11.0 +/- 0.8 years, height of 128.9 +/- 7.8 cm (-2.3 +/- 0.4 SD below the mean) and a mean adult predicted height of 151.8 +/- 10.1 cm served as controls and were simultaneously followed without therapy for the same study period.

MEASUREMENTS

Height and pubertal status were followed every 3 months during combined therapy and until final height of our patients was reached; bone ages were obtained every 6 months. Growth hormone deficiency was ruled out in all our subjects prior to beginning of the study by a normal response to oral clonidine and normal IGF-1 levels. Basal serum testosterone and/or oestradiol levels, as well as LH and FSH following administration of LH-releasing hormone were obtained before treatment and after 6 weeks and 4 months of combined therapy and every 6 months thereafter. Routine biochemistry as well as thyroid function tests were obtained at each visit.

RESULTS

Combined treatment resulted in an interruption of pubertal development with a suppression of gonadal steroids and of the LH response to LH-releasing hormone. Growth velocity decreased from 6.5 +/- 1.6 cm/year before treatment to 5.5 +/- 1.5 cm/year and 3.9 +/- 1.3 cm/year during the first and second year of treatment (P < 0.02 and P < 0.05, respectively) resulting in a height Z score reduction, declining from -2.4 +/- 04 to -2.6 +/- 0.7 SD. Bone age maturation declined averaging 0.75 bone age year/year of treatment but height SDS for bone age declined from -1.7 +/- 0.7 to -2.2 +/- 0.5 at the end of the second year of therapy with no improvement in predicted adult height (150.7 +/- 9.8 cm before and 150.0 +/- 8.0 after 2 years of therapy). After discontinuing treatment growth velocity did not improve and bone maturation advanced more rapidly (averaging 2.0 +/- 0.4 year/year of follow up) and the mean final height of our patients was 151 +/- 2.4 cm (-2.6 +/- 0.6 SD below the mean) which was not greater than the mean pretreatment predicted adult height and well below their target height; these results were also similar to those of the control population in whom the predicted adult height at the beginning of the study and after 2 years of follow up, was not different from their final height and well below their target height.

CONCLUSIONS

We conclude that combined rhGH and GnRH analogue therapy in short adolescents with normally timed puberty does not contribute to increase their final height above their pretreatment predicted adult height; we can therefore not recommend this form of therapy for this group of patients given the poor results obtained, as well as the cost of these medications and the

Growth hormone administration can improve growth in glucocorticoid-injected rats without affecting the lymphocytopenic effect of the glucocorticoid

Long-term glucocorticoid therapy as it is found in children with kidney transplants results in retarded longitudinal growth. The aim of the present study was to evaluate if growth hormone could improve longitudinal growth in glucocorticoid-injected experimental animals without affecting the immuno-suppressive effect of the glucocorticoid. 117 female Wistar rats were injected from the ages of 2-5 months with either saline, growth hormone (5 mg/kg/day), or glucocorticoid (methylprednisolone 1,3,6 or 9 mg/kg/day), alone or in combination with growth hormone (5 mg/kg/day). Body weight, nose-tail length and length of the lower extremity were measured continuously during the study. After death, femoral and tibial lengths, growth at the proximal, epiphyseal growth plate, muscle mass and immunological parameters were examined. Glucocorticoid administration dose-dependently decreased weight gain and growth (nose-tail length, growth of the lower extremity), lengths of femur and tibia, growth at the proximal, epiphyseal growth plate and muscle mass. Glucocorticoid administration decreased spleen and thymus weight as well as the white blood cell count (WBC count), mainly due to a decrease in lymphocyte number. For all glucocorticoid doses examined, growth hormone increased weight gain and growth (nose-tail length, growth of the lower extremity), lengths of femur and tibia, and muscle mass. The effects of growth hormone were, however, dose-dependently decreased by glucocorticoid administration. Growth hormone injection alone increased the WBC count due to an increase in the number of lymphocytes and monocytes. When the two hormones were administered concomitantly, growth hormone did not, however, reverse the lymphocytopenic effect induced by glucocorticoid administration. In conclusion, growth hormone can increase longitudinal growth and increase muscle mass in glucocorticoid-injected rats, if a glucocorticoid preparation of a short half-life is used. Growth hormone does not reverse the lymphocytopenic effect of glucocorticoid injections.

Growth hormone therapy with three dosage regimens in children with idiopathic short stature. European Study Group Participating Investigators

OBJECTIVE

In children with idiopathic short stature (ISS) we studied the growth-promoting effect at 4 years of recombinant human growth hormone (rhGH) therapy in three dose regimens and evaluated whether increasing the dosage after the first year could prevent a decline in height velocity (HV).

DESIGN

Included were 223 patients who were treated with subcutaneous administrations of rhGH 6 days per week. They were randomized to three groups: 3 IU/m2 body surface/day, 4.5 IU/m2/day, and 3 IU/m2/day during the first year and 4.5 IU/m2/day thereafter, corresponding with dosages of 0.2 and 0.3 mg/kg body weight/week, respectively. Growth was compared with a standard of 229 untreated children with ISS [ISS standard].

RESULTS

During the first year of treatment HV almost doubled and was higher with 4.5 IU/m2 than with 3 IU/m2. In the second year HV no longer differed among the groups, but increasing the dosage slowed the rate of the fall of HV. During 4 years of therapy the height SD score for age increased by a mean (SD) of 2.5 (1.0) [ISS standards], or 1.2 (0.7) (British standards), bone age increased by 4.8 (1.3) years, and predicted adult height SD score increased by 1.5 (0.7). After 4 years the results of the group with 4.5 IU/m2 were slightly better than those of the other groups. When dropouts were included in the analysis (assuming a stable height SD score after discontinuation of rhGH therapy), height gain was still significant.

CONCLUSIONS

During 4 years of rhGH therapy, growth and final height prognosis improved, slightly more with 4.5 IU/m2 than with 3 IU/m2 or 3 to 4.5 IU/m2. However, bone age advanced on average 4.8 years during this period; therefore, any effect on final height will probably be modest.

Effect of clonidine on the height of a child with glycogen storage disease type VI: a 13 year follow-up study

A 9-month-old male was found to have hepatomegaly when he was treated by his doctor for bronchitis. At the age of 2 years and 3 months, glycogen storage disease (GSD) of type VI (GSD VI) was diagnosed in this patient. Despite the recommended diet therapy, his growth was not good, changing under or along the line of -2.0 SD. At the age of 6 years, oral clonidine therapy (0.15 mg/day, 0.2 mg/m2 body surface per day) was started. Six to 10 months after the initiation of clonidine therapy, his height began to increase more than the values for -2.0 SD and once reached the value for -1.0 SD at the age of 10 years. His growth rate and bone age increased. Clonidine therapy was continued regularly for 7 years until the age of 13 years, 11 months. At that time his development was normal and his height reached 150.8 cm (-1.34 SD). However, cessation of the treatment at the patient's free will resulted in a reduction of the growth rate at age 15 years 6 months. These observations suggest the effect of clonidine therapy on height. Side effects were not noted during the clonidine therapy. Other clinical and laboratory findings of GSD VI also completely improved during treatment. In conclusion, administration of clonidine could be another treatment modality in children with GSD, not only of type VI but also I and III.

Effects of two years of growth hormone treatment in short, slowly growing non-growth hormone deficient children

Thirty-two short, slowly growing prepubertal children with normal GH levels (after clonidine stimulation and overnight sampling) were treated with GH hormone for 2 consecutive years at a dose of 0.1 IU/kg/day s.c. Fifteen similar children were followed for 2 years without therapy (controls). Height velocity increased in our treated group from 3.8 +/- 0.9 cm/yr to 7.3 +/- 1.3 cm/yr and 7.1 +/- 0.9 cm/yr in the first and second years of therapy, with 85.7% and 87.5% of our patients growing > 2 cm/yr above baseline. Height SDS changed from -2.4 +/- 0.4 to -2.0 +/- 0.7 in the first year and to -1.8 +/- 0.5 during the second year of treatment, while bone ages increased at a slightly higher rate than chronological ages. An increase in the final height predictions of our patients during therapy was noted. Height velocity increment in the control group was not significant and height SDS of this group did not change. GH therapy in short, slowly growing non-GH deficient children seems to be effective and safe in the short term; however, its efficacy in increasing the final height of this group of patients is still undetermined.

Lipids and apolipoproteins in growth hormone-deficient children during treatment

The role of growth hormone (GH) in regulating the transport of plasma lipoproteins has not been clearly defined, but past studies suggest that GH may influence cholesterol levels. This protocol was designed to evaluate possible changes in lipid and apolipoprotein status in GH-deficient children and children with neurosecretory dysfunction (NS) before GH therapy and at intervals after GH therapy was started. Twenty children with classic GH deficiency were evaluated, and 28% were hyperlipidemic at the onset of the study. Seven children were evaluated in the NS group, and only one (14%) showed an elevated total cholesterol (TC) greater than 200 mg/dL. The mean TC for all the GH-deficient children was elevated above the normal range, but not for the NS group. The mean apolipoprotein (apo) C-III level and its heparin-precipitated fraction (HP) were also elevated in the GH-deficient group, but only the apo C-III HP was elevated in the NS group. A standard replacement dose of recombinant methionyl GH was used, and therapy had no significant effect on TC or triglyceride (TG) levels. Apo C-III HP, a marker of hypertriglyceridemia, increased after the start of therapy, but no other lipoprotein levels changed significantly in the GH-deficient group. No changes were seen with treatment in the NS group. The longitudinal design of this study allowed demonstration of the later changes in the apolipoproteins and the presence of a distinct subset of patients with both GH deficiency and hypercholesterolemia. This study supports the role of GH in modulating lipid metabolism.

Changes in body composition, resting energy expenditure, and thermic effect of food in short children on growth hormone therapy

The effect of growth hormone (GH) treatment on body composition, resting energy expenditure (REE), and the thermic effect of food (TEF) was studied in 10 prepubertal boys (aged 6.2 to 9.5 years, with subnormal spontaneous GH secretion during the first 6 months of treatment [0.2 IU/kg.dl]). Patients were studied before and at 2, 4, and 6 months after commencing treatment. Height and weight increased significantly during treatment (112.2 +/- 4.5 to 117.2 +/- 6.0 cm and 18.0 +/- 2.8 to 20.8 +/- 3.2 kg, respectively). Body fat percent decreased significantly (15.93% +/- 4.08% to 11.97% +/- 3.30%, P < .0002), but was not different at 4 and 6 months. Total body potassium (TBK) increased significantly (39.15 +/- 5.77 to 48.70 +/- 6.35 g, P < .001) during treatment. When correcting for the expected changes in body composition over time, height and weight were still shown to increase, fat percent decreased significantly, but TBK and mid-arm muscle circumference (MAMC) were not different from the expected values. REE increased significantly during treatment, but when it was expressed per TBK or corrected for the change in kilograms of fat-free body mass (FFBM), it increased only at 2 months and stabilized thereafter. The TEF was increased at 2 and 4 months of treatment and returned to pretreatment levels at 6 months of treatment. Substrate utilization as studied by indirect calorimetry pointed toward a significant protein-sparing effect during the first 4 months of treatment; this change tended to disappear in resting energy metabolism by 6 months of GH treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Growth and metabolic consequences of growth hormone treatment in prepubertal short normal children

Growth and the metabolic effects of growth hormone were monitored in a randomised, controlled group of 41 short, normal, prepubertal children. The treated group received daily injections of growth hormone as Genotropin (Kabi Pharmacia) 30 IU/m2/week. Fifteen children in the treated group (21 children) have completed three years of treatment, have grown significantly more than 14 (of 20) untreated children, and have a significantly greater adult height prediction. They do, however, remain leaner (body fat 13.5% in the treated group, 18% in the untreated group) and relatively hyperinsulinaemic (insulin 66.7 pmol/l in the treated group, 44.5 in the untreated group) after three years compared with untreated children. Although growth hormone appears to improve the height potential of prepubertal short normal children, the long term outcome is still uncertain.

Use and abuse of human growth hormone

Recombinant human growth hormone (hGH) has been available for nearly a decade. Side effects are rare. Its efficacy in promoting growth acceleration has been widely confirmed in children with GH deficiency (GHD), Turner syndrome, idiopathic short stature, chronic renal failure, and a variety of other conditions. The dramatic increase in height velocity in the first year of therapy partially attenuates in subsequent years in all patient groups, and convincing final height data are only available in GHD and Turner syndrome. Pediatric endocrinologists continue to be troubled by definitions of GHD. Although profound GHD is relatively obvious, other patients with severe growth failure but borderline or normal endocrine testing also respond to hGH therapy. Thus many endocrinologists use auxologic criteria [e.g. low growth velocity, height < -3 standard deviation (SD), poor predicted adult height] as the de facto basis for therapy, leading to a blurred distinction between treatment of disease and enhancement of normal characteristics and, finally, raising questions about the ultimate benefit of hGH therapy. Brief clinical trials of hGH therapy in adults both with and without GHD have reported increased muscle mass, decreased fat, and improvement in quality of life. Internists may soon be faced with treatment decisions analogous to those confronting pediatricians, i.e. whether to use hGH to repair aspects of the normal aging process.

Combined treatment with growth hormone and luteinizing hormone releasing hormone-analogue (LHRHa) of pubertal children with familial short stature

We evaluated the 12 month growth of 18 pubertal children with familial short stature randomly assigned to clinical follow-up (group A), GH treatment alone (group B) and GH+LHRH analogue (LHRHa) treatment (group C). Height velocity increased significantly compared to baseline in groups A and B (4.7 +/- 0.4 vs 6.6 +/- 0.6 and 4.4 +/- 0.3 vs 8 +/- 1 respectively), but not in C (5 +/- 0.5 vs 6.5 +/- 0.4). Moreover in group B height and height prognosis standard deviation score SDS) also were higher (-2.2 +/- 0.2 vs -1.7 +/- 0.2 and 1.8 +/- 0.3 vs -1 +/- 0.2, respectively). Comparisons among the groups showed a significant increase in group B vs the other groups of height velocity SDS (3.9 +/- 1.3 vs 0.4 + 1 and 0.3 +/- 0.7) and of height prognosis SDS (-1 +/- 0.2 vs -2.4 +/- 0.3 and -2.4 +/- 0.3). In conclusion, after one-year treatment, GH seems to be more effective in stimulating growth than GH +/- LHRHa, even if studies of longer duration and/or follow-up are needed.

Characteristics of children with idiopathic short stature in the Kabi Pharmacia International Growth Study, and their response to growth hormone treatment. International Board of the Kabi Pharmacia International Growth Study

The auxological characteristics and the response to growth hormone (GH) treatment of children with idiopathic short stature were studied, using the database of the Kabi Pharmacia International Growth Study. Pretreatment data from a total of 271 children were analysed. The children were selected for a birth weight above -2 SDS. The correlation coefficient of birth weight SDS and birth length SDS was 0.51, compared with 0.72 for the reference population. Median length at birth was -0.6 SDS, which fell to -2.5 SDS by 3 years of age. Thereafter, there was no further loss in height SDS. The response to GH treatment was studied in 222 of these prepubertal children who were given six or seven injections/week over a 3-year period. During this time, the median height SDS increased from -2.5 to -1.5, with those children receiving more than 0.65 IU/kg/week having a greater gain in height SDS than those on 0.5 IU/kg/week or less. The degree of bone age delay did not appear to influence the response to GH therapy.

Clinical diagnoses of children with extremely short stature and their response to growth hormone

This study was undertaken to determine the prevalence of clinical diagnoses in a group of children with extremely short stature (standard deviation score for height, < -2.5) and to determine whether the classification might help in predicting response to human growth hormone (hGH) treatment. We classified 49 children referred consecutively to our outpatient clinic for evaluation of short stature with heights < -2.5 standard deviation score and bone ages < 9 years for girls or < 10 years for boys (to avoid an effect of puberty on the response to hGH). The diagnostic categories were growth hormone (GH) deficiency, constitutional delay, familial short stature, and primordial short stature. After referral, Turner syndrome was diagnosed in two children. The remaining 47 children were classified according to primary criteria, considered essential for the diagnosis, and secondary criteria, considered necessary but of lesser importance. There were five children, four children, no children, and one child classified, respectively, with GH deficiency, constitutional delay, familial short stature, and primordial short stature by using the most rigorous definitions of the diagnoses. There was significant overlap in the diagnoses other than GH deficiency. Growth hormone deficiency defined by the primary criterion of peak stimulated GH values < 5 micrograms/L was the most definitive. Of the 47 children, 7 were classified as GH deficient by this criterion and 5 were classified as GH deficient by the primary and secondary criteria. The mean pretreatment growth rate (3.1 +/- 1.9 cm/yr) of the group with stimulated GH values < 5 micrograms/L was significantly less than that in the other groups (4.2 +/- 1.5 cm/yr). The mean growth rate of the children with GH deficiency during treatment with hGH was greater than that in the other groups and was 3.4 times greater than the pretreatment growth rate. The mean growth rate of children in the other groups during hGH treatment was twofold greater than the pretreatment growth rate. We conclude that except for GH deficiency, children with an extreme degree of short stature are not easily classified by standard diagnostic criteria, and that most short children have a positive response to hGH therapy regardless of the diagnosis; therefore a specific clinical diagnosis should not be used to exclude children from hGH therapy.

Effects of nightly clonidine administration on growth velocity in short children without growth hormone deficiency: a double-blind, placebo-controlled study

Children with short stature, slowed linear growth velocity, and delayed skeletal maturation may secrete growth hormone (GH) normally in response to provocative stimuli but may also have spontaneous undersecretion of GH. Orally administered clonidine, an alpha 2-adrenergic agonist, is a potent acute stimulator of growth hormone releasing hormone-mediated pituitary GH release. We performed a double-blind, placebo-controlled crossover study of nightly oral clonidine therapy (0.1 mg/m2) in 10 short, slowly growing, non-GH-deficient (stimulated GH level > 15 micrograms/L) prepubertal boys (range, 6.1 to 12.2 years; mean height standard deviation score, -2.3 +/- 0.4). Results of 6 months of clonidine therapy were compared with the results of 6 months of placebo therapy; GH responsiveness was subsequently assessed in 7 of 10 patients. Growth velocity (4.9 +/- 0.6 cm/yr baseline) was not improved by clonidine (4.6 +/- 1.2 cm/yr) or placebo (5.2 +/- 1.2 cm/yr), but it increased (p < 0.001) with GH therapy (8.2 +/- 1.3 cm/yr). Clonidine therapy similarly did not significantly affect plasma levels of insulin-like growth factor I or bone age maturation. Diminution in clonidine-stimulated peak GH levels was not observed after long-term oral clonidine therapy. Thus, in contrast to previous non-placebo-controlled studies, nightly clonidine therapy did not increase growth velocity or plasma insulin-like growth factor I levels. Subsequent acceleration in growth velocity during GH therapy suggests that a proposed increase in clonidine-induced endogenous GH secretion does not result in an effective growth-promoting stimulus.

Constitutional delay of growth and adolescence

Constitutional delay of growth and adolescence (CDGA) is characterized by simultaneous retardation of growth, skeletal maturation and sexual development. Primarily longitudinal growth is impaired. The late occurrence of puberty is a secondary phenomenon brought about by the retarded physical development. Plasma levels of sex hormones and gonadotrophin correlate with bone age, not with chronological age. The provocation tests for growth hormone (GH) show normal results. In contrast, the spontaneous secretion of GH, measured half-hourly through the night or over 24 hours, is markedly reduced. Plasma somatomedin C is diminished. According to these data, CDGA is not a genuine GH deficiency but represents a cybernetic disorder coinciding with a false threshold for GH. As shown by large series of investigations, the final height of the patients lies on average 1.85 SD below the mean of healthy adults, with large individual variations. The decision as to whether treatment by growth promoting hormones should be performed should be made with regard to the individual height prognosis. With GH in physiological doses growth velocity can be considerably increased. Bigger doses of the hormone appear to be necessary in order to enhance final height. Treatment by anabolics and testosterone increases height velocity only, not adult height.

Therapy of growth hormone deficiency

Treatment with human growth hormone in growth hormone deficient patients will improve growth rate significantly, initially demonstrating catch-up growth and later bringing forth a normal growth rate. During childhood, a dose of 0.3-0.6 units/kg body weight per week (or 14 units/m2 body surface area per week) is recommended, but during puberty the dose should be increased by 50-100%. The goal of therapy is the attainment of a normal final height, which in the past has often not been fulfilled. This was partly due to the inadequate supply of growth hormone. Since recombinant human growth hormone is now available in unlimited amounts, all patients can be treated continuously. The shorter the child is at time of presenting for therapy, the lower final height will be. It is mandatory to start therapy as early as possible. Concomitant hormonal deficiencies must be corrected by adequate therapy. Despite the fact that growth hormone is diabetogenic, supplementary therapy will not induce diabetes mellitus. Subtle changes in the immune system can be detected but no clinical correlates, such as increased susceptibility to infection, exist. Induction of leukaemia has been suspected as a possible side-effect of human growth hormone treatment but so far there is insufficient evidence to prove that growth hormone is oncogenic.

Long-term treatment with growth hormone of children with short stature and normal growth hormone secretion

Children with short stature but normal growth rate and/or normal growth hormone response to sleep and secretagogues were treated with recombinant methionyl human growth hormone, 0.3 mg/kg per week. In each year of treatment, about 80% of the subjects maintained an increase in growth rate greater than the defined limit (greater than 1 cm/yr above pretreatment growth rate) for continuation of human growth hormone treatment. Comparison of the group that continued to respond to human growth hormone with the group that did not maintain an accelerated growth rate did not reveal differences in bone age delay, sleep or secretagogue-stimulated human growth hormone secretion, degree of short stature either absolute or relative to target height, and somatomedin C concentration before or after initiation of therapy. The group that failed to respond to the human growth hormone treatment in the first year of treatment was younger and had a higher pretreatment growth rate. Review of the longitudinal growth curves revealed five patterns of response to human growth hormone treatment: (1) failure to increase growth rate in two subjects with height SD scores within 1 SD of target height, (2) failure to increase growth rate in five subjects with height SD scores greater than 1 SD less than the target height, (3) acceleration in growth rate in three subjects that was not maintained until achievement of a height within 1 SD of the target height, (4) acceleration of growth rate in five subjects that was maintained until achievement of a height within 1 SD of the target height, and (5) acceleration in growth rate that was maintained during the 3 years of treatment in 15 subjects who had not attained a height within 1 SD of the target height. We conclude that human growth hormone treatment of some but not all short children with "normal" growth hormone secretion will result in sustained acceleration of growth rate and attainment of prepubertal heights that are closer to but do not exceed their genetic height potential. A clinical trial of human growth hormone may be necessary to determine which subjects will benefit from the treatment.

An overview of the diagnoses in the Kabi Pharmacia International Growth Study

This paper provides an overview of the diagnoses of patients entered in the Kabi Pharmacia International Growth Study (KIGS). By May 1991, data from a total of 5377 children treated with growth hormone (GH) were included in the main database. Of these children, 2691 were classified as having idiopathic GH deficiency (GHD), 866 as having GHD of known origin, and 1820 as having other causes of short stature. The majority of patients with idiopathic GHD have no history of perinatal trauma. In the patients with GHD of known origin, 137 were congenital cases and 729 acquired GHD. The largest number of congenital cases (114) belonged to the group of central malformations (e.g. septo-optic dysplasia and empty sella syndrome). Of the cases with acquired GHD, 73% were associated with tumours or leukaemia. Other causes of short stature include 12 groups of diagnoses, with more than 150 cases in four of them (idiopathic short stature, 635; defined syndromes with chromosomal aberrations, 337, of which 304 were Turner's syndrome; defined syndromes without chromosomal aberrations, 157; intrauterine growth retardation without stigmata, 366). Analysis of the KIGS data allows modern GH therapy for GHD to be compared with older treatment modalities. The study offers the advantage of larger numbers of cases than can be achieved in individual trials and allows assessment of the use of GH therapy for GHD of comparatively uncommon causes.

Treatment of short normal children with growth hormone--a cautionary tale?

41 short normal children were randomly allocated either to daily injections of growth hormone (rhGH) at 30 IU/m2 per week or to no treatment. 6 months of rhGH therapy produced up to 76% loss of fat mass and up to 25% increase in lean body mass (LBM). These changes were significantly different from those in the untreated group. LBM was the main determinant of resting energy expenditure (REE) expressed as kJ/24 h. REE expressed as kJ/kg LBM per 24 h correlated negatively with height, which was responsible for 66% of the variance in REE kJ/kg LBM per 24 h. Short children therefore expend more energy than tall children in fulfilling basic metabolic needs. After 6 months REE kJ/24 h increased significantly in treated children. However, treated children did not differ significantly from untreated children in REE kJ/kg LBM per 24 h. rhGH does not therefore seem to have a specific effect upon REE. The possibility that rhGH produces profound metabolic effects should limit its use in otherwise healthy children until the mechanism of action is more clearly elucidated.