Long-term results of growth hormone treatment in France in children of short stature: population, register based study

Isolated childhood growth hormone deficiency: a 30-year experience on final height and a new prediction model

PURPOSE

We aimed to evaluate the near-final height (nFHt) in a large cohort of pediatricpatients with growth hormone deficiency (GHD) and to elaborate a new predictive method of nFHt.

METHODS

We recruited GHD patients diagnosed between 1987 and 2014 and followed-up until nFHt. To predict the values of nFHt, each predictor was run in a univariable spline.

RESULTS

We enrolled 1051 patients. Pre-treatment height was -2.43 SDS, lower than parental height (THt) (-1.09 SDS, p < 0.001). The dose of recombinant human GH (rhGH) was 0.21mg/kg/week at start of treatment. nFHt was -1.08 SDS (height gain 1.27 SDS), higher than pre-treatment height (p < 0.001) and comparable to THt. 1.6% of the patients were shorter than -2 SDS from THt. The rhGH dose at nFHt was 0.19 mg/kg/week, lower than at the start (p < 0.001). The polynomial regression showed that nFHt was affected by gender, THt, age at puberty, height at puberty, age at the end of treatment (F = 325.37, p < 0.0001, R² 87.2%).

CONCLUSION

This large national study shows that GHD children can reach their THt. The rhGH/kg/day dose significantly decreased from the start to the end of the treatment. Our model suggests the importance of a timely diagnosis, possibly before puberty, the beneficial effect of long-term treatment with rhGH, and the key-role of THt. Our prediction model has a very acceptable error compared to the majority of other published studies.

Long-term response to recombinant human growth hormone treatment: a new predictive mathematical method

INTRODUCTION

Recombinant GH has been offered to GH-deficient (GHD) subjects for more than 30 years, in order to improve height and growth velocity in children and to enhance metabolic effects in adults.

AIM

The aim of our work is to describe the long-term effect of rhGH treatment in GHD pediatric patients, suggesting a growth prediction model.

MATERIAL AND METHODS

A homogeneous database is defined for diagnosis and treatment modalities, based on GHD patients afferent to Hospital Regina Margherita in Turin (Italy). In this study, 232 GHD patients are selected (204 idiopathic GHD and 28 organic GHD). Each measure is shown in terms of mean with relative standard deviations (SD) and 95% confidence interval (95% CI). To estimate the final height of each patient on the basis of few measures, a mathematical growth prediction model [based on Gompertzian function and a mixed method based on the radial basis functions (RBFs) and the particle swarm optimization (PSO) models] was performed.

RESULTS

The results seem to highlight the benefits of an early start of treatment, further confirming what is suggested by the literature. Generally, the RBF-PSO method shows a good reliability in the prediction of the final height. Indeed, RMSE is always lower than 4, i.e., in average the forecast will differ at most of 4 cm to the real value.

CONCLUSIONS

In conclusion, the large and accurate database of Italian GHD patients allowed us to assess the rhGH treatment efficacy and compare the results with those obtained in other Countries. Moreover, we proposed and validated a new mathematical model forecasting the expected final height after therapy which was validated on our cohort.

Medical, psychological and social features in a large cohort of adults with Prader-Willi syndrome: experience from a dedicated centre in France

BACKGROUND

Prader-Willi syndrome (PWS) is a developmental genetic disorder characterised by a variable expression of medical, cognitive and behavioural symptoms. In adulthood, the prevalence and severity of these symptoms determine the quality of life of the affected persons. Because of their rare disease condition, data on health and social problems in adults with PWS are scarce. In this research, we present medical, psychological and social features of a large cohort of adults admitted to a specialised PWS centre in France and analyse the differences according to genotype, gender and age.

METHODS

Data from 154 patients (68 men/86 women), with a median age of 27 years (range 16-54), were collected during their stay in our centre. Clinical histories were completed using information from parents or main caregivers, and the same medical team performed the diagnosis of different clinical conditions. Statistical analyses were performed to determine the influence of factors such as genotype, age or gender.

RESULTS

Paternal deletion genotype was the most frequent (65%) at all ages. Most patients had mild or moderate intellectual disability (87%). Only 30% had studied beyond primary school and 70% were in some special educational or working programme. Most of them lived in the family home (57%). The most prevalent somatic comorbidities were scoliosis (78%), respiratory problems (75%), dermatological lesions (50%), hyperlipidaemia (35%), hypothyroidism (26%), Type 2 diabetes mellitus (25%) and lymph oedema (22%). Some form of psychotropic treatment was prescribed in 58% of subjects, and sex hormones in 43%. Patients with deletion had a higher body mass index (44 vs. 38.9 kg/m(2)) and displayed higher frequency of sleep apnoeas. Non-deletion patients received insulin treatment (19% vs. 4%) and antipsychotic treatment (54.8% vs. 32.7%) more frequently. No difference was observed in the prevalence of Type 2 diabetes between the two genotype groups. Patients >27 years of age had a higher rate of comorbidities (Type 2 diabetes, hypertension, respiratory problems and lymph oedema). Gender differences were minor.

CONCLUSIONS

Adult patients with PWS showed high prevalence of comorbid health problems that need to be monitored for early treatment. Some of them are influenced by genotype and age. Another salient problem concerns the lack of adapted structures for better social integration. Further data about the real life and health conditions of adults with PWS are necessary to further our knowledge of the natural history of the disease and to design appropriate care strategies.

Efficacy and safety of Samtropin™ recombinant human growth hormone; a double-blind randomized clinical trial

Background

Recombinant human growth hormone (rhGH) can increase the growth rate in growth hormone deficient children (GHD). In this randomized clinical trial, we compared the efficacy and side effects of an Iranian brand; Samtropin with Norditropin.

Methods

The GHD children were randomly treated either with standard dose of Samtropin or Norditropin rhGH for one year. Upstanding height, height standard deviation score (HSDS), growth velocity (GV), serum levels of insulin like growth factor-1 (IGF-1), and bone age (BA) were determined before and during one year treatment concomitant side effects of treatment.

Results

We evaluated 22 subjects; 12 on Samtropin and, 10 on Norditropin. In each group, mean age was 12 yr and 50% of them were male. The mean differences in height, HSDS, IGF-1 and BA by Norditropin before and after 12 months were 8.8 cm, 0.5, 49 ng/ml and 2.8 yr, respectively. These measures by Samtropin were 9.1 cm, 0.6, 133 ng/ml, and 1.7 yr, respectively without any significant difference. The mean of GV by Samtropin was 9.1 vs. 8.8 cm by Norditropin without significant difference. Since the efficacy of Samtropin was found to be similar to Norditropin after 12 months; we switched to use only Samtropin for the next 12 months. The mean differences in height, HSDS, GV and BA in 20 children between months 12 and 24 were 7.0 cm, 1.6, 2.1 cm/yr and 1.0 yr, respectively (P < 0.001). We also found a non-significant decrease in IGF-1 levels. No side effects were observed.

Conclusions

We need to conduct a post marketing surveillance with a large sample size in order to confirm our findings.

Trial registration

Registration code number in the Iranian Registry of Clinical Trials (IRCT): IRCT1138901181414N11.

A mathematical model in the analysis of the response to growth hormone treatment in pediatric patients with diagnosis of growth hormone deficiency

In the literature, few studies analyze the effect of GH therapy on height, preferring a more indirect approach, where factors influencing the total pubertal and pre-pubertal growth in GH-deficient patients are evaluated and subsequently used to estimate the overall effect at the end of the therapy; unfortunately, this approach does not quantify the real growth gain in treated patients. Using a non-parametric Empirical Bayes approach, our study analyzes the growth response to GH treatment in a homogeneous cohort of 317 patients with pituitary GH deficiency who were enrolled during their pre-pubertal stage in the GH Piedmont Registry (Italy), between January 2000-October 2008, and have at least 2 yr of follow-up. To estimate the growth curve for males and females, a non-parametric regression model was fitted, applying Empirical Bayes techniques. A validation of the model was also performed. Improvement was evident in both genders, since both males and females mean growth curve, which started below the 3rd percentile at the beginning of the therapy, reached the 10th percentile of the Tanner curve at the end of observation (17 yr old for males and 14 yr old for females); the estimation procedure achieved a good precision. The methodological approach allows for fitting a model able to evaluate longitudinally the response to GH treatment, by means of estimating the overall growth curve, even in presence of sparse information about children heights.

Long-term mortality after recombinant growth hormone treatment for isolated growth hormone deficiency or childhood short stature: preliminary report of the French SAGhE study

CONTEXT

Little is known about the long-term health of subjects treated with GH in childhood, and Safety and Appropriateness of Growth hormone treatments in Europe (SAGhE) is a study addressing this question.

OBJECTIVE

The objective of the study was to evaluate the long-term mortality of patients treated with recombinant GH in childhood in France.

DESIGN

This was a population-based cohort study.

SETTING

The setting of the study was a French population-based register.

PARTICIPANTS

A total of 6928 children with idiopathic isolated GH deficiency (n = 5162), neurosecretory dysfunction (n = 534), idiopathic short stature (n = 871), or born short for gestational age (n = 335) who started treatment between 1985 and 1996 participated in the study. Follow-up data on vital status were available in September 2009 for 94.7% of the patients.

MAIN OUTCOME MEASURES

All-cause and cause-specific mortality was measured in the study.

RESULTS

All-cause mortality was increased in treated subjects [standardized mortality ratio (SMR) 1.33, 95% confidence interval (CI) 1.08-1.64]. In a multivariate analysis adjusted for height, the use of GH doses greater than 50 μg/kg · d was associated with mortality rates using external and internal references (SMR 2.94, 95% CI 1.22-7.07, hazard ratio 2.79, 95% CI 1.14-6.82). All type cancer-related mortality was not increased. Bone tumor-related mortality was increased (SMR 5.00, 95% CI 1.01-14.63). An increase in mortality due to diseases of the circulatory system (SMR 3.07, 95% CI 1.40-5.83) or subarachnoid or intracerebral hemorrhage (SMR 6.66, 95% CI 1.79-17.05) was observed.

CONCLUSIONS

Mortality rates were increased in this population of adults treated as children with recombinant GH, particularly in those who had received the highest doses. Specific effects were detected in terms of death due to bone tumors or cerebral hemorrhage but not for all cancers. These results highlight the need for additional studies of long-term mortality and morbidity after GH treatment in childhood.

Long-term safety and efficacy of the recombinant human growth hormone Omnitrope® in the treatment of Spanish growth hormone deficient children: results of a phase III study

INTRODUCTION

This phase III study in growth hormone (GH) deficient (GHD) children with growth retardation was designed to demonstrate the safety and efficacy of longterm treatment with the recombinant human GH Omnitrope® (Sandoz BioPharmaceuticals, Holzkirchen, Germany).

METHODS

Treatment-naïve, prepubertal Spanish children (n=70) with isolated GHD were treated with Omnitrope 0.03 mg/kg/day subcutaneously. Changes in height, height standard deviation score (HSDS), height velocity (HV), HV standard deviation score (HVSDS), serum insulin-like growth factor (IGF)-1, and insulin-like growth factor binding protein (IGFBP)-3 levels were recorded.

RESULTS

Omnitrope treatment provided a good growth response after 4 years, shown by a significant increase in mean body height (31.1 cm [95% CI: 29.6-32.6]), HSDS (Tanner) (1.42 [1.13-1.70]), HV (2.4 cm [1.7-3.1]), and HVSDS values (3.5 [2.7-4.3]). Mean IGF-1 and IGFBP-3 serum levels also increased significantly.

CONCLUSION

At a dose of 0.03 mg/kg/day, Omnitrope was safe, effective, and well tolerated during long-term treatment of children with GHD.

Developments in administration of growth hormone treatment: focus on Norditropin® Flexpro®

Recombinant human growth hormone is used for the treatment of growth failure in children and metabolic dysfunction in adults with growth hormone deficiency. However, conventional growth hormone therapy requires daily subcutaneous injections that may affect treatment adherence, and subsequently efficacy outcomes. To enhance potential treatment adherence, improved ease of use of growth hormone delivery devices and long-acting growth hormone formulations are now being developed. Flexpro(®), approved by the US Food and Drug Administration in March 2010, is the most recent pen device developed by Novo Nordisk A/S to deliver Norditropin(®). It is a multidose, premixed, preloaded, disposable pen device that requires relatively less force to inject and does not require refrigeration after initial use. Dose adjustments can be optimized by small dose increments of the pen delivery device at 0.025 mg, 0.05 mg and 0.1 mg. In addition, for patients with needle anxiety, NovoFine(®) needles, some of the shortest and thinnest available, and Autocover(®), which hides the needle during injections, can be used with the Flexpro pen device. This article reviews the Norditropin Flexpro pen device in the context of other growth hormone delivery devices, sustained-release growth hormone formulations in development, and future prospects.

Differential effects of insufflated, subcutaneous, and intravenous growth hormone on bone growth, cognitive function, and NMDA receptor subunit expression

The objective of this study was to characterize the effect of inhalable growth hormone (GH) delivered by an insufflator to the lungs of hypophysectomized Sprague Dawley rats. In the first cohort, the safety and efficacy of the insufflated GH were evaluated. Three experimental groups (n = 7 per group) were treated with GH for 15 d: One group received sc injection of GH daily at 200 microg/kg (SC200). Two other groups received GH by insufflation daily: 200 microg/kg (INS 200) and 600 microg/kg (INS 600). In the second set of experiments, GH was administered in three routes [SC200, INS200, intravenous (IV200)] (n=10) for 5 d, and escape latency and N-methyl D-aspartate (NMDA) receptor expression were evaluated. In the first cohort, INS200 showed similar bioactivity as SC200 in growth promotion, tibial growth, as well as escape latency on the 12th day of treatment. Insufflated GH was well tolerated without significant inflammatory responses. In the second cohort, expression of the NMDA receptor 1 and 2B in hippocampus measured after 3 or 6 d of daily treatments were significantly higher in INS200 as compared to IV200, consistent with the improvement of the escape latency. In summary, the inhalable form of GH delivered by intratracheal insufflation was safe, and its bioactivity was comparable to sc injection both in promotion of growth and acquisition of learning ability. If applied properly to human, inhalable GH would be effective for growth promotion and possibly for several disorders caused by underexpression of NMDA receptors.

Inhaled growth hormone (GH) compared with subcutaneous GH in children with GH deficiency: pharmacokinetics, pharmacodynamics, and safety

BACKGROUND

Delivery of GH via inhalation is a potential alternative to injection. Previous studies of inhaled GH in adults have demonstrated safety and tolerability.

OBJECTIVE

We sought to assess safety and tolerability of inhaled GH in children and to estimate relative bioavailability and biopotency between inhaled GH and sc GH.

DESIGN/METHODS

This pediatric multicenter, randomized, double-blind, placebo-controlled, crossover trial had two 7-d treatment phases. Patients received inhaled GH and sc GH in the alternate phase. Placebo was administered by the route opposite from active drug. GH and IGF-I levels were measured at multiple time points. Pharmacokinetics were assessed using noncompartmental methods.

RESULTS

Twenty-two GH-deficient children aged 6-16 yr were treated. Absorption of GH appeared to be faster after inhalation with maximum serum concentrations measured at 1-4 h compared with 2-8 h for sc GH. Mean relative bioavailability for inhaled GH was 3.5% (90% confidence interval 2.7-4.4%). Mean relative biopotency, based on IGF-I response, was 5.5% (confidence interval 5.2-5.8%). Similar dose-dependent increases in mean serum GH area under the curve and IGF-I changes from baseline were seen after inhaled and sc GH doses. Inhaled GH was well tolerated and preferred to injection. No significant changes in pulmonary function tests were seen.

CONCLUSIONS

In this first pediatric trial of GH delivered by inhalation, it was well tolerated and resulted in dose-dependent increases in serum GH and IGF-I levels. This study establishes that delivery of GH via the deep lung is feasible in children.

Final height in Swedish children with idiopathic growth hormone deficiency enrolled in KIGS treated optimally with growth hormone

AIM

To assess final height in children with growth hormone deficiency (GHD) treated with human recombinant growth hormone (GH).

METHODS

Final height data for 401 Swedish children with idiopathic GHD and treated with GH, included in KIGS (Pfizer International Growth Database) between 1987 and spring 2006, were analysed retrospectively. Data were grouped according to sex, age and severity of GHD. Height at entry into KIGS, at the onset of puberty and near final height were analysed between groups.

RESULTS

Groups were heterogeneous for GHD, which ranged from partial to severe. For all groups, mean final height corrected for mid-parental height was within the normal Swedish height range. In patients with severe GHD, mean final height was almost identical to mean normal Swedish height. About 16% of patients showed disproportionality (short legs) at final height and were significantly shorter than other patients. The parents of these children also demonstrated short stature.

CONCLUSION

Children with idiopathic GHD receiving GH replacement therapy can achieve a final height that as a group is within the normal range and all achieve a height within their genetic potential.

Final height in children with idiopathic growth hormone deficiency treated with a fixed dose of recombinant growth hormone

There is no consensus regarding the optimal dosing of recombinant human growth hormone (rhGH) for children with growth hormone deficiency (GHD). Our objective was to evaluate the final adult height (FAH) in children with idiopathic GHD treated with a fixed rhGH dose of 0.18 mg/kg/week. We reviewed all charts of patients with idiopathic GHD treated with rhGH since 1985 who reached FAH. Ninety-six patients were treated for an average of 5.4 years. The mean age was 11.9 years, the mean height -2.87 standard deviation score (SDS) and the mean FAH was -1.04 SDS. Females had a lower predicted adult height than males at the initiation of therapy (-2.0 vs. -1.01 SDS; p = 0.0087) but a higher FAH - predicted adult height (1.08 vs. 0.04 SDS; p = 0.0026). In multiple regression analysis, the FAH SDS was positively related to the midparental height SDS, the height SDS at GH initiation and growth velocity during the first year of therapy, and negatively correlated with peak GH and bone age at initiation (r(2) = 0.51; p < 0.005). Treatment of children with idiopathic GHD with a fixed dose of 0.18 mg/kg/week rhGH is sufficient to reach FAH within 2 SDS of the normal population range (84%) with an average FAH within -0.5 SDS of midparental height.

Prediction of adult height in growth-hormone-treated children with growth hormone deficiency

CONTEXT

Several studies have searched for factors that significantly influence adult height (AH) of children with GH deficiency (GHD) who have been treated with biosynthetic GH, but a prediction model for AH has not yet been presented.

OBJECTIVE

Our objective was to develop models for prediction of AH, using information available at the start of GH treatment or after 1 yr of treatment.

DESIGN AND SETTING

For this retrospective study, data were collected from the National Registry of Growth Hormone Treatment in Children, which contained data of Dutch children treated with GH.

PATIENTS/INTERVENTION

Patients included males born before 1985 and females born before 1987 with either diagnosis of GHD (syndromes, tumors, and other diseases were excluded) or a maximal GH response during provocation tests of less than 11 ng/ml, treated with biosynthetic GH for at least 1 yr. To be able to use the complete group of 342 children for the development of the models, multiple imputation was used for missing values.

MAIN OUTCOME MEASURE

We assessed AH sd scores (SDS).

RESULTS

Each prediction model contained both target height SDS and current height SDS. The change in height SDS during the first year proved an important predictor for AH. In all models, addition of GH dose was not significant. The percent explained variance, after correction for overfitting, ranged from 37% (prepubertal children, prediction at start) to 60% (pubertal children, prediction after 1 yr).

CONCLUSION

The presented prediction models give accurate predictions of AH for children with GHD at start and after 1 yr of GH treatment. They are useful tools in the treatment of these children.

Adult height in patients with permanent growth hormone deficiency with and without multiple pituitary hormone deficiencies

CONTEXT

It has been reported that patients with multiple pituitary hormone deficiencies (MPHDs) achieve a greater final height, compared with patients with isolated GH deficiency (IGHD). However, the outcome of patients with permanent GH deficiency (GHD) has not yet been reported.

OBJECTIVES

The objectives of the study were to evaluate and compare adult height data and the effect of spontaneous or induced puberty after long-term treatment with GH in young adults with either permanent IGHD or MPHD.

DESIGN AND SETTING

This was a retrospective multicenter study conducted in university research hospitals and a tertiary referral endocrine unit.

PATIENTS AND METHODS

Thirty-nine patients with IGHD (26 males, 13 females) and 49 with MPHD (31 males, 18 females), diagnosed at a median age of 7.7 and 6.9 yr, respectively, were reevaluated for GH secretion after adult height achievement (median age 17.6 and 19.8 yr). The diagnosis of permanent GHD was based on peak GH levels less than 3 microg/liter after an insulin tolerance test or peak GH levels less than 5 microg/liter after two different tests. Fifteen subjects had idiopathic GHD and seventy-three had magnetic resonance imaging evidence of congenital hypothalamic-pituitary abnormalities. Height sd score (SDS) was analyzed at diagnosis, the onset of puberty (either spontaneous or induced), and the time of GH withdrawal.

RESULTS

The subjects with IGHD entered puberty at a median age of 12.6 yr (females) and 13.4 yr (males). Puberty was induced at a median age of 13.5 and 14.0 yr, respectively, in males and females with MPHD. Median height SDS at the beginning of puberty was similar in the IGHD and MPHD subjects. Total pubertal height gain was similar between patients with IGHD or MPHD. Median adult height was also not significantly different between IGHD and MPHD patients (males, 168.5 vs. 170.3 cm; females, 160.0 vs. 157.3 cm). The adult height SDS of the IGHD subjects was positively correlated with height at the time of diagnosis and with total pubertal height gain. Conversely, the adult height SDS of the MPHD subjects was positively correlated with both the duration of GH treatment and height SDS at the time of GHD diagnosis.

CONCLUSIONS

Adult height in patients with permanent IGHD and spontaneous puberty is similar to adult height in patients with MPHD and induced puberty.

Incidence and prevalence rate estimation of GH treatment exposure in Piedmont pediatric population in the years 2002-2004: Data from the GH Registry

OBJECTIVE

The aim of this study is to estimate the annual incidence and prevalence rate of the GH treatment exposure in patients under the age of 18 treated for hypopituitarism or isolated GH deficiency (GHD) in Piedmont, during the period January 1, 2002 to December 31, 2004.

METHODS

The selection criteria for recombinant human GH (rhGH) treatment in childhood were approved by the Ministry of Health in Italy in the yr 1998. The present analysis is based on data from the Registry of subjects receiving GH therapy (GH Registry) made up of the 918 pediatric patients (age <18 yr) with a diagnosis of GHD (excluding Prader-Willi and Turner syndromes and other conditions), diagnosed in the period January 1, 2002 - December 31, 2004. The case series has been described as regards the number of cases per year of diagnosis; the prevalence and incidence rates, calculated per 10,000 (per ten thousand) inhabitants, are given for each year of the study period.

RESULTS

The prevalence rate increases slightly from 8.62 per thousand in 2002 to 9.44 per thousand in 2004 and the incidence rates estimated were 2.49 per ten thousand, 1.86 per ten thousand and 1.97 per ten thousand in the yr 2002, 2003 and 2004, respectively.

CONCLUSION

The Piedmont GH Registry represents the first database available in Italy and could set an example for the other Italian regions as well.

Long-Term Evolution of Endocrine Disorders and Effect of GH Therapy in 35 Patients with Pituitary Stalk Interruption Syndrome

We report long-term evolution of endocrine functions and the results of GH treatment in 35 patients (26 male and 9 female) with pituitary stalk interruption. At diagnosis, mean chronological age was 4.8 +/- 2.7 years, mean SDS for height -3.1 +/- 0.8 with a bone age retardation of 2.3 +/- 1.3 years and a mean SDS for growth velocity of -0.5 +/- 1.1; 80% presented complete GH deficiency (GHD) and 20% partial GHD; thyroid deficiency was present in 47.1% of children with complete GHD but absent in all partial GHD. Diagnosis was made during the first months of life in only 2 patients while 23% presented with severe neonatal distress; neonatal signs were only observed in the group with pituitary height below 2 mm (45.7% of patients). GHD was isolated in 40.6% of patients below 10 years while multiple hormone deficiencies was consistent at completion of growth in all patients. Height gain was significantly higher in patients who started GH treatment before 4 years (p = 0.002). GH treatment is very effective: in 13 patients, final height was -0.4 +/- 1.0, total height gain 3.2 +/- 1.2 and distance to target height -0.3 +/- 1.6 SDS.

High incidence of scrapie induced by repeated injections of subinfectious prion doses

To clarify the mechanisms leading to the development of Creutzfeldt-Jakob disease in some recipients of pituitary-derived human growth hormone (hGH), we investigated the effects of repeated injections of low prion doses in mice. The injections were performed, as in hGH-treated children, by a peripheral route at short intervals and for an extended period. Twelve groups of 24 mice were intraperitoneally inoculated one, two, or five times per week for 200 days with 2 x 10(-5) to 2 x 10(-8) dilutions of brain homogenate containing the mouse-adapted C506M3 scrapie strain. Sixteen control mice were injected once a week for 200 days with a 2 x 10(-4) dilution of normal brain homogenate. Of mice injected in a single challenge with a scrapie inoculum of a 2 x 10(-4), 2 x 10(-5), or 2 x 10(-6) dilution, 2/10, 1/10, and 0/10 animals developed scrapie, respectively. Control mice remained healthy. One hundred thirty-five of 135 mice injected with repeated prion doses of a 2 x 10(-5) or 2 x 10(-6) dilution succumbed to scrapie. Of mice injected with repeated scrapie doses of a 2 x 10(-7) or 2 x 10(-8) dilution, 52/59 and 38/67 animals died of scrapie, respectively. A high incidence of scrapie was observed in mice receiving repeated doses at low infectivity, whereas there was no disease in mice that were injected once with the same doses. Repeated injections of low prion doses thus constitute a risk for development of prion disease even if the same total dose inoculated in a single challenge does not induce the disease.

Growth hormone secretory pattern and response to treatment in children with short stature followed to adult height

OBJECTIVE

To compare the relative utility of GH stimulation tests and assays of spontaneous GH secretion as predictors of change in height standard deviation score at the end of GH treatment in children with short stature.

PATIENTS AND METHODS

We retrospectively studied 116 children (67 boys and 49 girls) with subnormal growth rates and short stature, defined as a height of more than 2SD below the mean for age and sex. The patients were classified according to their pattern of findings on baseline pharmacological GH stimulation tests and a 12-h assay of nocturnal spontaneous GH secretion. Twenty-eight patients (24%) had normal hormone levels by both methods (group I); 14 (12%) had normal levels by stimulation tests but subnormal levels by the physiological assay (group II); 48 (41%) had subnormal levels on pharmacological stimulation, with normal physiologic levels (group III); and 26 (22%) had subnormal levels by both methods (group IV). All children in groups II and IV, and 27 in group III, designated IIIb, were treated with recombinant GH at 0.7 U (0.23 mg/kg) of body weight per week. GH secretory patterns were related to final height SD scores and other growth parameters, after the patients had attained their adult stature 6.7 +/- 2.2 years (SD) after GH evaluation.

RESULTS

The five groups were similar with respect to mean baseline height SD scores for chronological as well as bone age. Whether assessed as absolute or parentally adjusted (relative) values, mean gains in height SD scores were significantly greater in treated patients with physiological hormone deficiency (groups II and IV) than in those with normal hormone levels (group I, untreated controls). Relative height gains were 1.03 +/- 1.45 cm (6.6 +/- 9.28 cm) and 1.85 +/- 1.21 cm (SDS; 11.8 +/- 7.74 cm) in groups II and IV respectively, compared with only 0.11 +/- 0.42 cm (0.7 +/- 2.68 cm) in group I (P < 0.01 and P < 0.001). GH treatment failed to improve either the absolute or parentally adjusted final height of patients with GH deficiency by stimulation tests but normal levels by physiological assay.

CONCLUSION

Long-term administration of GH to short children with normal spontaneous GH secretion is not associated with an appreciable increase in adult height.

Can some growth hormone (GH)-deficient children benefit from combined therapy with gonadotropin-releasing hormone analogs and GH? Results of a retrospective study

Recombinant GH (rGH) treatment does not invariably correct height deficits in GH-deficient children once puberty has begun. The addition of GnRH analogs (GnRHa) to delay puberty has been advocated, but published results are few and sometimes conflicting. We retrospectively compared GH-deficient children treated with rGH and GnRHa for at least 1 yr after entering puberty and having attained their final height (n = 23) with a matched control group treated only with rGH. Overall, combined therapy did not significantly increase final height relative to rGH alone. However, the shortest girls at the onset of puberty (<25th percentile) benefited more than the tallest (>75th percentile) in both final height relative to predicted height and pubertal catch-up growth. In the control group, patients having experienced intrauterine growth retardation (IUGR) attained a lower mean final height than patients without IUGR (difference significant in boys, but not in girls). In the combined therapy group, IUGR did not affect the final height of either sex. Our results suggest that two populations might benefit most from combined GnRHa and rGH therapy: girls particularly short at the onset of puberty and patients who had experienced IUGR. Further prospective studies are required to confirm these preliminary hypothesis.

Growth hormone therapy

Since 1958 growth hormone (GH) has been used as substitution treatment for children with GH deficiency. At present, it is clear that a dose of 0.23 mg/kg/week can lead to a final height close to target height, but in view of the wide inter-individual variation, alternative regimens based on invidualizing the dosage with the help of prediction models are being investigated. The best strategy during puberty (increase the dosage, delay puberty) is still uncertain. The value of GH in idiopathic short stature is still heavily debated, although the average final height gain on 0.33 mg/kg/week is 5-7 cm. GH is efficacious in short stature due to chronic renal failure and Prader-Willi syndrome. In other conditions insufficient data are available. There are few side-effects.

Adult height after long term treatment with recombinant growth hormone for idiopathic isolated growth hormone deficiency: observational follow up study of the French population based registry

OBJECTIVE

To evaluate the efficacy of recombinant growth hormone for increasing adult height in children treated for idiopathic isolated growth hormone deficiency.

DESIGN

Observational follow up study.

SETTING

Population based registry.

PARTICIPANTS

All 2852 French children diagnosed as having isolated idiopathic growth hormone deficiency whose treatment started between 1987 and 1992 and ended before 1996.

MAIN OUTCOME MEASURES

Change in height between the start of treatment and adulthood; classification of patients according to whether treatment was completed as scheduled or stopped early.

RESULTS

Adult height was obtained for 2165 (76%) patients. The mean dose of growth hormone at start of treatment was 0.42 IU/kg/week. Height gain was 1.1 (SD 0.9) standard deviation (SD) scores, resulting in an adult height of -1.6 (0.9) SD score (girls, 154 (5) cm; boys, 167 (6) cm). Patients who completed the treatment gained 1.0 (0.7) SD score of height in 3.6 (1.4) years. Patients with treatments stopped early gained 0.6 (0.6) SD score in 2.7 (1.4) years while receiving treatment and a further 0.4 (0.9) SD score after the end of treatment. Most of the variation in height gain was explained by regression towards the mean, patients' characteristics, and delay in starting puberty. Severe growth hormone deficiency was associated with better outcome. Each year of treatment was associated with a gain of 0.2 SD score(1.3 cm).

CONCLUSION

The effect of growth hormone is unclear in many patients treated for so called idiopathic isolated growth hormone deficiency. Most of the patients have pubertal delay and a spontaneous growth potential, which must be taken into account when measuring the effect and cost effectiveness of treatments. Growth hormone deficiency should be clearly distinguished from pubertal delay, and criteria should restrict the definition to patients with severely and permanently altered growth hormone secretion as our results support the use of growth hormone in such patients. Long term trials are required for most patients currently treated.

Body composition, IGF-I and IGFBP-3 concentrations as outcome measures in severely GH-deficient (GHD) patients after childhood GH treatment: a comparison with adult onset GHD patients

If GH therapy of children with GH deficiency (GHD) has been adequate, body composition should be comparable to that of patients who have undergone normal childhood development and become hypopituitary thereafter. To assess this, body composition was determined in 92 patients with childhood onset (CO) GHD, aged 18-30 yr, who had been treated to final height with GH for 8.98 +/- 4.30 yr and had stopped treatment 1.57 +/- 1.20 yr previously, but who remained GHD (assessed by a GH stimulation test and IGF-I values). These were compared with 35 age-matched GH-naïve hypopituitary patients with adult onset (AO) GHD. Lean body mass, fat mass, and total bone mineral content were assessed by dual energy x-ray absorptiometry and corrected for actual height. CO patients were shorter (CO height, -1.18 +/- 1.16 SD score; AO height, -0.38 +/- 1.12 SD score; P < 0.001) and had lower body mass index (CO, 23.19 +/- 5.76 kg/m(2); AO, 28.9 +/- 6.27 kg/m(2); P < 0.001) than the AO group. Although there were gender differences, within genders CO patients had lower lean body mass, fat mass, and bone mineral content (P < 0.001 in all cases) compared with AO patients. Standard deviation scores for IGF-I (CO female, -9.2 +/- 3.1; AO female, -5.2 +/- 2.6; CO male, -6.4 +/- 2.7; AO male, -3.5 +/- 2.3; P < 0.001 within each gender) and IGFBP-3 (CO female, -3.5 +/- 2.5; AO female, -1.7 +/- 1.5; CO male, -2.8 +/- 2.0; AO male, -1.1 +/- 1.6; P < 0.001 within each gender) were significantly lower in the CO group. These results suggest that patients with CO GHD who were treated to final height suffer a significant maturational deficit despite GH replacement during childhood.

Growth and adult height in GH-treated children with nonacquired GH deficiency and idiopathic short stature: the influence of pituitary magnetic resonance imaging findings

We analyzed the final height of 146 short children with either nonacquired GH deficiency or idiopathic short stature. Our purpose was 1) to assess growth according to the pituitary magnetic resonance imaging findings in the 63 GH-treated children with GH deficiency and 2) to compare the growth of the GH-deficient patients with normal magnetic resonance imaging (n = 48) to that of 32 treated and 51 untreated children with idiopathic short stature (GH peak to provocative tests >10 microg/liter). The mean GH dose was 0.44 IU/kg.wk (0.15 mg/kg.wk), given for a mean duration of 4.6 yr. Among the GH-deficient children, 15 had hypothalamic-pituitary abnormalities (stalk agenesis), all with total GH deficiency (GH peak <5 microg/liter). They were significantly shorter and younger at the time of diagnosis than those with normal magnetic resonance imaging, had better catch-up growth (+2.7 +/- 0.9 vs. +1.3 +/- 0.8 SD score; P < 0.01), and reached greater final height (-1.1 +/- 1.0 vs. -1.7 +/- 1.0 SD score; P < 0.05). Among patients with normal magnetic resonance imaging, there was no difference in catch-up growth and final height between partial and total GH deficiencies. GH-deficient subjects with normal magnetic resonance imaging and treated and untreated patients with idiopathic short stature had comparable auxological characteristics, age at evaluation, and target height. Although they had different catch-up growth (+1.3 +/- 0.8, +0.9 +/- 0.6, and +0.7 +/- 0.9 SD score, respectively; P < 0.01, by ANOVA), these patients reached a similar final height (-1.7 +/- 1.0, -2.1 +/- 0.8, and -2.1 +/- 1.0 SD score, respectively; P = 0.13). Pituitary magnetic resonance imaging findings show the heterogeneity within the group of nonacquired GH deficiency and help to predict the response to GH treatment in these patients. The similarities in growth between the GH-deficient children with normal magnetic resonance imaging and those with idiopathic short stature suggest that the short stature in the former subjects is at least partly due to factors other than GH deficiency.

Optimizing gh therapy in adults and children

Until the advent of modern neuroradiological imaging techniques in 1989, a diagnosis of GH deficiency in adults carried little significance other than as a marker of hypothalamo-pituitary disease. The relatively recent recognition of a characteristic clinical syndrome associated with failure of spontaneous GH secretion and the potential reversal of many of its features with recombinant human GH has prompted a closer examination of the physiological role of GH after linear growth is complete. The safe clinical practice of GH replacement demands a method of judging overall GH status, but there is no biological marker in adults that is the equivalent of linear growth in a child by which to judge the efficacy of GH replacement. Assessment of optimal GH replacement is made difficult by the apparent diverse actions of GH in health, concern about the avoidance of iatrogenic acromegaly, and the growing realization that an individual's risk of developing certain cancers may, at least in part, be influenced by cumulative exposure to the chief mediator of GH action, IGF-I. As in all areas of clinical practice, strategies and protocols vary between centers, but most physicians experienced in the management of pituitary disease agree that GH is most appropriately begun at low doses, building up slowly to the final maintenance dose. This, in turn, is best determined by a combination of clinical response and measurement of serum IGF-I, avoiding supraphysiological levels of this GH-dependent peptide. Numerous studies have helped define the optimum management of GH replacement during childhood. The recent requirement to measure and monitor GH status in adult life has called into question the appropriateness of simplistic weight- and surface area-based dosing regimens for the management of GH deficiency in childhood, with reliance on linear growth as the sole marker of GH action. It is clear that the monitoring of parameters other than linear growth to help refine GH therapy should now be incorporated into childhood GH treatment protocols. Further research will be required to define the optimal management of the transition from pediatric to adult GH replacement; this transition will only be possible once the benefits of GH in mature adults are defined and accepted by pediatric and adult endocrinologists alike.

Long-term therapy with recombinant human growth hormone (Saizen) in children with idiopathic and organic growth hormone deficiency

In an open-label study, 69 children with organic or idiopathic growth hormone deficiency (GHD) were treated with recombinant human growth hormone (Saizen) for an average of 64.4 mo, with treatment periods as long as 140.9 mo. Auxologic measurements, including height velocity, height standard deviation score, and bone age, were made on a regular basis. The data suggest that long-term treatment with Saizen in children with GHD results in a positive catch-up growth response and proportionate changes in bone age vs height age during treatment. In addition, long-term Saizen therapy was well tolerated, with the majority of adverse events related to common childhood disorders or existing baseline medical conditions and not to study treatment. There were no significant changes in laboratory safety data or vital signs, and no positive antibody tests for Saizen.

Growth response, pubertal growth and final height in Greek children with growth hormone (GH) deficiency on long-term GH therapy and factors affecting outcome

The growth data of 156 children (100 boys, 56 girls) with growth hormone deficiency (GHD), treated with human growth hormone (GH) for 5.7+/-3.7 years, from 1970-1997, were retrospectively analyzed to assess the efficacy of GH treatment and the factors involved. 62.2% of the studied population had idiopathic GHD (IGHD) and 35.2% had organic GHD (OGHD). At initiation of treatment, chronological age (CA) was 10.1+/-4.0 years in children with IGHD and 9.7+/-4.0 years in those with OGHD, while bone age (BA) was 7.0+/-3.7 and 7.7+/-3.2 years, respectively. The SDS of the growth velocity during the first year of therapy (GV1) was negatively related to CA at start of therapy (r = -0.53, p = 0.01). 109 children have reached final height (FH): 67 boys (FH = 165.3+/-6.3 cm) and 42 girls (FH = 153.9+/-5.4 cm). FH SDS was not significantly different from target height (TH) SDS. In the total group, FH SDS was positively related to height SDS for CA and BA at start of therapy (p = 0.01, p = 0.001, respectively), to TH SDS (r = 0.40, p = 0.001), and to GV1 (r = 0.33, p = 0.001). TH SDS was not different between the IGHD and OGHD groups (-1.02+/-0.8 vs. -0.94+/-6.9). The height gain at puberty did not differ between the groups with induced or spontaneous puberty in boys (23.7+/-8.6 vs. 25.4+/-6.9, not significant), while in girls it was higher in the group with spontaneous puberty (12.7+/-7.3 vs. 20.0+/-9.0, p = 0.008). The age and height at start of puberty was higher in girls and boys with induced puberty. In the total group, the FH SDS of children with induced puberty was higher in comparison with those with spontaneous puberty (-1.0+/-0.8 vs. -1.7+/-0.9, p = 0.001) and it was positively related to the height at start of puberty. When the two sexes were analyzed separately, the difference reached significance only in boys. In conclusion, children with GHD on GH treatment achieved a final height which was comparable to their genetic potential. The FH of children with OGHD was not different from those with IGHD. The age and height at start of puberty were the most significant determining factors for FH. Hence, a better FH might be expected by delaying or arresting puberty.

Growth and endocrine disorders in multisystem Langerhans' cell histiocytosis

INTRODUCTION

Langerhans' cell histiocytosis is a rare disorder, with diabetes insipidus occurring in up to half of patients. Causes of growth failure include the illness itself, treatments used and growth hormone insufficiency.

PATIENTS AND METHODS

We identified all patients with an endocrinopathy secondary to Langerhans' cell histiocytosis (LCH). Growth data were analysed from all patients with multisystem involvement.

RESULTS

Of 144 patients with multisystem LCH, 50 had an endocrinopathy, 49 of whom had diabetes insipidus. Growth hormone insufficiency (GHI) was present in 21 patients, seven of whom had other anterior pituitary deficiencies as well (gonadotrophin deficiency + GHI n = 2, gonadotrophin deficiency + TSH deficiency + GHI n = 2, panhypopituitarism n = 3). GH insufficiency, the development of which appeared to be independent of pituitary radiation, occurred at a median age of 8.3 years (4.7-18 years) and at a median interval of 3.5 years (0-11.8 years) after diagnosis of LCH. The median height SDS at diagnosis of growth hormone insufficiency was -2.9. Thirteen of the patients with growth hormone insufficiency attained final height with a median height SDS of -1.2. The final height SDS of 15 patients without GH insufficiency was closer to target height SDS, but not statistically different from that of the GH insufficient group.

CONCLUSIONS

GH therapy significantly improves growth in GH insufficient patients with Langerhans' cell histiocytosis. Early institution of GH therapy may further improve height outcome. However, most children with Langerhans' cell histiocytosis regardless of endocrine function, failed to reach target height.

Is there a place for combined therapy with GnRH agonist plus growth hormone in improving final height in short statured children?

The availability of recombinant human growth hormone (GH) and the optimization of substitutive therapy have improved final growth in children with GH deficiency, but despite this some of them fail to grow to their genetic potential. In particular, this may occur in patients who started the substitutive therapy too late and/or in whom bone age progressed too fast during GH administration. In these patients, with unfavorable auxological characteristics, the administration of a GnRH agonist in combination with GH may slow down bone maturation and prolong prepubertal growth, mimicking, to some extent, the growth pattern of patients with GH + Gn deficiency who grow better than children with isolated GHD. A different condition in which such a combined therapy might be used is the short normal child. As they are short but normally-growing children, the onset of puberty is in general appropriate for their chronological age but precocious for their height age. Thus, slowing down pubertal maturation may increase the time available for growth. GH would sustain growth during both GnRHa administration and after its withdrawal, when puberty starts again. Our preliminary results suggest that the administration of GH + GnRHa in combination may have a positive effect on final height in selected children with isolated GHD and in short normal children.

[Catch-up growth in growth hormone deficit children treated with GH since the first year of life]

Long-term effects of growth hormone (GH) treatment were studied in 59 GH deficient (GHD) children, whose treatment was started before the age of 1 year, during the period 1978-1992, under the supervision of the France-Hypophyse Association. Mean duration of treatment was 8 +/- 3.6 years. At the last evaluation, 20 patients (34%) had a height above normal mean for age, and 50 (85%) had a height above the second lower standard deviation (SD) for age. Final height prediction performed in 29 patients was greater than target size (-0.35 +/- 1.4 SD vs -0.56 +/- 0.79 SD). These results show that early treatment of GHD infants allows normal statural growth in the majority of the cases; in addition, they underline the importance of early diagnosis of GH deficiency.

When and how to combine growth hormone with a luteinizing hormone-releasing hormone analogue

The effect of combined treatment with growth hormone (GH) and a luteinizing hormone-releasing hormone (LHRH) analogue, or GH alone, on pubertal height gain was assessed in an uncontrolled study in 15 boys and 10 girls with GH deficiency (GHD). Seven boys and six girls were treated with GH alone (group 1), and eight boys and four girls were treated with a combination of GH and an LHRH analogue during puberty (group 2). Mean ages (+/- SD) at the start of GH treatment and at the onset of puberty were significantly lower in group 2 (8.0 +/- 3.3 years and 11.2 +/- 0.8 years, respectively, in boys, and 6.3 +/- 1.6 years and 10.8 +/- 0.7 years in girls) than in group 1 (12.8 +/- 1.9 years and 13.7 +/- 1.4 years in boys, and 11.2 +/- 1.0 years and 12.5 +/- 1.2 years in girls). Height at the onset of puberty was less in group 2 than in group 1, but the difference was significant only for the boys. Combination treatment was started at a mean age of 11.7 +/- 1.2 years in boys and 11.5 +/- 1.0 years in girls. The duration of the combination treatment was 5.1 +/- 1.5 years in boys and 2.3 +/- 0.7 years in girls. The duration of the period between the onset of puberty and the end of GH treatment was significantly longer in group 2 (6.8 +/- 1.2 years in boys and 5.5 +/- 1.0 years in girls) than in group 1 (4.3 +/- 1.6 years in boys and 3.6 +/- 1.4 years in girls). The pubertal height gain was also significantly greater in group 2 (36.7 +/- 6.5 cm in boys and 29.0 +/- 8.3 cm in girls) than in group 1 (21.9 +/- 4.1 cm in boys and 18.6 +/- 4.1 cm in girls). Final height was significantly greater in group 2 than in group 1 in boys. Although there was no significant difference in final height between groups in the girls, the change in height SDS from the start of GH treatment until final height was significantly greater in group 2 (2.7 +/- 1.6 in boys and 4.5 +/- 0.5 SD in girls) than in group 1 (1.0 +/- 0.8 in boys and 1.8 +/- 0.9 SD in girls), in both boys and girls. In conclusion, it appears that combination of an LHRH analogue and GH may increase the pubertal height gain and the final height of children with GHD. The improvement is attributed to the prolongation of the treatment period, permitting slow bone maturation, and to the maintenance of height velocity. This combination treatment appears to be more effective in boys than girls. To fully assess this therapeutic approach, prospective controlled studies are needed.

Final height in idiopathic growth hormone deficiency: the KIGS experience. KIGS International Board

Final height was evaluated in 369 patients with idiopathic growth hormone deficiency (IGHD) enrolled in KIGS--the Pharmacia & Upjohn International Growth Database. At the start of growth hormone (GH) therapy, the patients were 9.8 years of age, their mid-parental height SDS was -0.8, and their height SDS was -3.1. Of the 369 patients, 50% had multiple hormone deficiencies, and puberty was induced in 31%. Patients were 18 years of age at completion of GH therapy, and had received GH at a dose of 0.49 IU/kg/week (0.16 mg/kg/week), with a mean of 5.2 injections/week for 8.1 years. Final height SDS was -1.5, final minus initial height SDS was 1.7 and final minus mid-parental height SDS was -0.5. A Swedish subgroup (n = 69) received conventional GH therapy throughout at 0.65 IU/kg/week (0.22 mg/kg/week), with seven injections/week for a mean of 9.4 years. These patients achieved their genetic potential (final minus mid-parental height SDS, 0.03), with a normal final height SDS of -0.3. For the total group, the following variables were associated with final height: mid-parental height SDS (r = 0.62), injection frequency (r = 0.37), duration of GH treatment (r = 0.28), peak stimulated GH concentration (r = -0.25), age (r = -0.19) (all p < 0.001) and height velocity SDS in the first year of treatment (r = 0.20, p = 0.004). In conclusion, genetic potential, expressed as the mid-parental height, is the variable with the greatest identified influence on final height during GH treatment in IGHD. Current GH regimens will lead to a normal height and attainment of mid-parental height. However, higher dose, individualized GH regimens are likely to be necessary for patients with IGHD who are disadvantaged at the time of commencing GH therapy, such as those with short parents, those whose treatment began in late childhood or adolescence and those with less severe GHD.

Shortcomings of the randomized controlled trial: a view from the boondocks

The randomized controlled trial (RCT), despite its well-known limitations, continues to be regarded as a gold standard in determining whether an intervention does more harm than good. Some recent evidence suggests that it tends to overvalue the modalities it tests. Moreover, the accuracy with which the disorder under consideration is diagnosed can be critical to the performance of a new intervention designed for it. When technological progress allows us to diagnose milder instances, some therapies, possibly useful in dire circumstances, will appear ineffective if most of a trial population is at low risk. Human individuality makes it impossible to duplicate a RCT. As a result, Popper's criterion of falsifiability may not be met and so the carrying out of a large-scale therapeutic experiment may not be a scientific activity. Finally, it is doubtful whether group probabilities derived from RCTs can be safely applied to individuals. These and other reservations concerning the applicability of the RCT to clinical practice are discussed.

Pharmacological testing for the diagnosis of growth hormone deficiency

Evaluation of growth hormone (GH) secretion using pharmacological GH stimulation tests (GHSTs) remains current practice, although the reliability of GHSTs has been questioned and many pitfalls have been pointed out. We have analysed all the 6,373 GHSTs which led to the initiation of GH therapy in 3,233 children treated in France from 1973 to 1989. Eleven different pharmacological tests were used, and 62 out of the 66 theoretical pairs of tests were used at least once. The most frequent combination of tests was used in 12.7% of patients. Reliability of GH peak measured by comparing the results of two tests in the same patient was poor, as measured by intraclass correlation coefficients (all under 0.8). Multivariate analysis identified several parameters positively or negatively associated with peak plasma GH. We believe that several of these factors (i.e. weight standard deviation score (SDS), genetic target height SDS and nature of the agent) identify biases in the diagnosis of GH deficiency (GHD). In addition, we re-evaluated GH secretion in 208 young adults formerly treated with GH for childhood onset GHD. Peak plasma was superior or equal to 10 ng/ml in 81% of patients with former idiopathic GHD. We conclude that the current use of GHSTs as well as the criteria for idiopathic childhood GHD should be questioned.