Priming with testosterone enhances stimulated growth hormone secretion in boys with delayed puberty

Beyond the bias! Sex distribution in paediatric growth hormone deficiency reexamined

OBJECTIVES

Various biases pertaining to stature account for a male sex predominance in growth hormone deficiency (GHD) cases diagnosed by endocrinology clinics. This manuscript will assess the sex distribution when biases are minimised.

METHODS

Retrospective chart review was conducted on patients diagnosed with GHD between 3 and 16 years of age. The sex distribution of cases was ascertained according to: (1) peak GH (pGH) by groups; based on growth hormone provocative testing, (2) pituitary gland imaging results, and (3) isolated GHD (IGHD) versus multiple pituitary hormone deficiencies (MPHD). The relative frequency of each sex was compared according to these subgroups with significance evaluated at α = .05 level.

RESULTS

Of the 5880 clinic referrals for short stature, there were 3709 boys (63%) and 2171 girls (37%). Of these, 20% of boys (n = 745) and 15.3% of girls (n = 332) underwent provocative testing for GHD. Of those tested, 39.2% of boys (n = 292) and 32.2% of girls (n = 107) were diagnosed with GHD, all p < .001. There was a male predominance in GHD cases based on pGH or GHD severity. Though not significant, girls were more likely than boys to have MPHD (p = .056), even across pGH groups (p = .06). Both boys and girls had a similar distribution of imaging abnormalities.

CONCLUSION

Stratifying by sex, we found similar percentages of pituitary imaging abnormalities (including tumours) and the number of pituitary hormone deficiencies in boys and girls as the cause of GHD. For these classifications, we did not find the historically reported male sex predominance.

Sex steroid priming for growth hormone stimulation testing in children and adolescents with short stature: A systematic review

OBJECTIVE

Growth hormone stimulation testing (GHST) is used to diagnose growth hormone deficiency (GHD) in children. As sex steroids impact on anterior pituitary function, there is concern around the efficacy of GHST in peripubertal children, where endogenous sex steroid levels are low. Sex steroid priming before GHST is thought to improve test efficacy in these children, however evidence to support its use in clinical practice is limited. In this systematic review, we addressed the following research questions: Does priming increase GH stimulation test efficacy in peripubertal children? Does priming identify those who would benefit most from treatment in terms of final height? Is there evidence for an optimal sex-steroid priming regimen?

DESIGN, PATIENTS, MEASUREMENTS

The study was registered with PROSPERO and conducted according to PRISMA guidelines. We searched Medline, Cochrane-Library, Scopus, EMBASE and Web-of-Science and included all studies that included GHST in both primed and unprimed children. A GH cut-off of 7 µg/L was used as a threshold for GHD. Study quality was assessed using the Risk-Of-Bias in Non- Randomized Studies (ROBINS-I) tool or the revised Cochrane risk-of-bias tool for Randomised trials.

RESULTS

Fifteen studies met our inclusion criteria, of which 4/15 (27%) were randomised control trials. The majority (9/15) of the studies indicated that priming increases growth hormone response upon GHST in peripubertal children, increasing test specificity. Two studies investigated final height after treatment based on the results of primed versus unprimed GHST. These results indicate that growth hormone treatment based on results of a primed GHST improve outcomes compared with treatment based on an unprimed test.

CONCLUSION

Sex-steroid priming increases the growth hormone response during GHST, resulting in fewer patients meeting the threshold required for a diagnosis of GHD. Unnecessary GH treatment may be avoided in some patients without a detrimental effect on final height. Numerous sex-steroid priming regimens have been used in clinical practice and the majority appear to be effective, but an optimal regimen has not been determined.

Macimorelin Acetate for the Diagnosis of Childhood-onset Growth Hormone Deficiency

Growth hormone provocation testing forms the cornerstone of the diagnosis of childhood growth hormone deficiency in clinical practice. Despite the widespread use of these tests, various criticisms have been levelled against them, such as the labour-intensive nature of the tests, their potential for serious adverse effects and their questionable reproducibility. Macimorelin acetate, a ghrelin mimetic approved for the diagnosis of adult growth hormone deficiency, could serve an unmet need in the diagnosis of childhood-onset growth hormone deficiency based on its good tolerability and benign side effect profile.

Growth Hormone Stimulation Testing: To Test or Not to Test? That Is One of the Questions

The evaluation of children with short stature includes monitoring over a prolonged period to establish a growth pattern as well as the exclusion of chronic medical conditions that affect growth. After a period of monitoring, evaluation, and screening, growth hormone stimulation testing is considered when the diagnosis of growth hormone deficiency (GHD) is entertained. Though flawed, growth hormone stimulation tests remain part of the comprehensive evaluation of growth and are essential for the diagnosis of growth hormone (GH) deficiency. Variables including testing length, growth hormone assay and diagnostic cut off affect results. Beyond the intrinsic issues of testing, results of GH stimulation testing can be influenced by patient characteristics. Various factors including age, gender, puberty, nutritional status and body weight modulate the secretion of GH.

Growth hormone deficiency and replacement in children

Growth hormone deficiency (GHD) is a rare but treatable cause of short stature. The diagnosis requires a careful evaluation of clinical history, physical examination and appropriate interpretation of longitudinal growth, with specific features for each period of life. Other clinical findings, in addition to growth failure, may be present and can be related to the etiology and to associated hormone deficiencies. Despite more than 50 years since the first reports of provocative tests of growth hormone (GH) secretion for the diagnosis of GHD, the interpretation of the results remains a matter of debate. When GHD is confirmed, GH treatment is recommended. Treatment is effective and safe, but requires daily injections during many years, which can affect adherence. At the end of longitudinal growth, during the transition phase, it might be necessary to re-evaluate GH secretion. This review summarizes and updates the recent information related to GHD in children, as well the recommendations for treatment.

When They're Done Growing, Don't Forget They May Still Need Growth Hormone

The effect of the growth hormone (GH) in promoting linear growth is well known; however, less recognized by practitioners especially pediatric, are its metabolic properties. This may be because the deleterious effects of improperly treated or untreated growth hormone deficiency (GHD) can present beyond the pediatric years. In addition, clinicians may lack familiarity with the potential issues that can arise due to inadequately treated GHD. Considering information from both the basic sciences research and clinical medicine, pediatric practitioners should be cognizant about the metabolic effects of GH. They should also be equipped to provide anticipatory guidance to patients regarding the importance of adherence to therapy in GHD and be prepared to transition patients with permanent GHD from pediatric GH supplementation to adult GH dosing. With a lack of proper transitioning, adverse outcomes may present beyond childhood.

Clinical benefits of sex steroids given as a priming prior to GH provocative test or as a growth-promoting therapy in peripubertal growth delays: Results of a retrospective study among ENDO-ERN centres

OBJECTIVES

Sex steroids, administered as a priming before GH stimulation tests (GHST) to differentiate between growth hormone deficiency (GHD) and constitutional delay of growth and puberty (CDGP) or as growth-promoting therapy using low-dose sex steroids (LDSS) in CDGP, are much debated. We aimed to compare auxological outcomes of CDGP or GHD children undergoing primed or unprimed GHST and to evaluate LDSS treatment in CDGP.

DESIGN

Retrospective study among three paediatric University Hospitals in Italy and UK.

METHODS

184 children (72 females) aged 12.4 ± 2.08 years underwent primed (/P⁺ ) or unprimed (/P^- ) GHST and were followed up until final height (FH). CDGP patients were untreated (CDG P^- ) or received LDSS (CDGP⁺ ). The cohort included 34 CDG P^- /P⁺ , 12 CDGP⁺ /P⁺ , 51 GHD/P⁺ , 29 CDG P^- /P^- , 2 CDGP⁺ /P^- and 56 GHD/P^- . FH standard deviation score (SDS), Δ SDS FH-target height (TH) and degree of success (-1 ≤ Δ SDS FH-SDS TH ≤ +1) were outcomes of interest.

RESULTS

GHD/P⁺ had better FH-SDS (-0.87 vs -1.49; P = .023) and ΔSDS FH-TH (-0.35 vs -0.77; P = .002) than CDGP^- /P⁺ . Overall, GHD/P⁺ showed the highest degree of success (90%, P = .006). Regardless of priming, both rhGH and LDSS improved degree of success compared to no treatment (89% and 86% vs 63%, P = .0009). GHD/P⁺ showed a trend towards a higher proportion of permanent GHD compared to GHD/P^- (30.43% vs 15.09%; P = .067).

CONCLUSION

In peripubertal children, priming before GHST improves diagnostic accuracy of GHST for idiopathic GHD. LDSS treatment improves auxological outcomes in CDGP.

Childhood growth hormone deficiency, a diagnosis in evolution: The intersection of growth hormone history and ethics

In 1958 the first recorded case of a patient treated with human growth hormone for growth hormone deficiency was published. Since that time, the source and availability of human growth hormone have changed. With the increased availability of growth hormone, there has been an uptrend in the level below which childhood growth hormone deficiency is diagnosed based on provocative GH stimulation testing. This increase is despite better specificity of growth hormone assays in addition to a lack of supportive evidence regarding appropriate normal values. With these trends the diagnosis of childhood growth hormone deficiency is evolving, and clinicians should be aware that this may have potential ethical implications.

Differential diagnosis between constitutional delay of growth and puberty, idiopathic growth hormone deficiency and congenital hypogonadotropic hypogonadism: a clinical challenge for the pediatric endocrinologist

INTRODUCTION

Differential diagnosis between constitutional delay of growth and puberty (CDGP), partial growth hormone deficiency (pGHD) and congenital hypogonadotropic hypogonadism (cHH) may be difficult. All these conditions usually present with poor growth in pre- or peri-pubertal age and they may recur within one familial setting, constituting a highly variable, but somehow common, spectrum of pubertal delay.

EVIDENCE ACQUISITION

Narrative review of the most relevant English papers published between 1981 and march 2020 using the following search terms "constitutional delay of growth and puberty," "central hypogonadism," "priming," "growth hormone deficiency," "pituitary," "pituitary magnetic resonance imaging," with a special regard to the latest scientific acquisitions.

EVIDENCE SYNTHESIS

CDGP is by far the most prevalent entity in boys and recurs within families. pGHD is a rare, often idiopathic and transient condition, where hypostaturism presents more severely. Specificity of pGHD diagnosis is increased by priming children before growth hormone stimulation test (GHST); pituitary MRI and genetic analysis are recommended to personalize future follow-up. Diagnosing cHH may be obvious when anosmia and eunuchoid proportions concomitate. However, cHH can either overlap with pGHD in forms of multiple pituitary hormone deficiencies (MPHD) or syndromic conditions either with CDGP in family pedigrees, so endocrine workup and genetic investigations are necessary. The use of growth charts, bone age, predictors of adult height, primed GHST and low dose sex steroids (LDSS) treatment are recommended.

CONCLUSIONS

Only a step-by-step diagnostic process based on appropriate endocrine and genetic markers together with LDSS treatment can help achieving the correct diagnosis and optimizing outcomes.

Needle-Free and Needle-Based Growth Hormone Therapy in Children: A Pooled Analysis of Three Long-Term Observational Studies

BACKGROUND

Treatment with growth hormone (GH) is standard clinical practice in children with GH deficiency (GHD) or Turner syndrome (TS). Hitherto, no long-term data on auxological outcome and safety of Zomacton® have been published. Data comparing needle-free administration (NF) and needle injection (NI) of GH are very sparse.

AIMS

To analyse longitudinal auxological outcome and safety data of GH treatment-naïve patients diagnosed with GHD or TS and to compare NF and NI in a real-life setting.

METHODS

Pooled auxological data and safety information from three consecutive prospective observational Zomacton® studies covering 22 years of treatment were analysed and NF was compared to NI.

RESULTS

The safety cohort comprised 1,595 patients who received at least one GH dose. The auxological outcome cohort comprised 856 treatment-naïve patients with follow-up data ≥12 months. Height-SDS and height velocity improved significantly during the first 3 years of treatment. Documented choice of device was available for 658 patients (NF 69.1%, NI 30.9%). NF administration was non-inferior to NI. No previously unknown safety signals occurred.

CONCLUSION

Real-life data show that treatment with Zomacton® improves auxological outcome parameters without new safety concerns. NF administration of GH represents a useful alternative to NI in children with growth disorders.

Evaluation of growth hormone stimulation testing in children

OBJECTIVE

To evaluate the use and interpretation of growth hormone (GH) stimulation tests used across the UK for diagnosing GH deficiency.

BACKGROUND

Previous studies show poor consensus on the use of GH stimulation tests. Sex steroid priming and retesting in the transition period are areas not previously surveyed.

DESIGN

Data were collected from tertiary paediatric endocrinologists, paediatricians with a specialist interest in endocrinology and biochemists across the UK over 6 months through distributing electronic surveys.

RESULTS

At least three different GH stimulation tests were used by 33% of departments. Glucagon and insulin doses varied most, and sampling frequency varied most using insulin. All laboratories use a recommended chemiluminescence immunoassay with an acceptable coefficient of variability. The GH peak for diagnosing GH deficiency varied from 6 to 8 μg/l. A wide range of clinical scenarios prompted retesting in the transition period, suggesting nonstandardized current practice. Seventy-five per cent of departments use sex steroid priming, but follow criteria variously combining bone age, chronological age and pubertal stage, together with variations in steroid type and dose.

CONCLUSIONS

Although a contentious diagnostic test, GH stimulation tests remain the gold standard for diagnosing GH deficiency. Our data suggest that together with variation in indication, protocol and interpretation, there is considerable variation in current practices pertaining to priming and retesting in transition. Given the current financial climate and the need for careful resource management, this study emphasizes the considerable need for consensus in the investigation, diagnosis and long-term follow-up of these children, at least nationally if not internationally.

Isolated growth hormone deficiency (GHD) in childhood and adolescence: recent advances

The diagnosis of GH deficiency (GHD) in childhood is a multistep process involving clinical history, examination with detailed auxology, biochemical testing, and pituitary imaging, with an increasing contribution from genetics in patients with congenital GHD. Our increasing understanding of the factors involved in the development of somatotropes and the dynamic function of the somatotrope network may explain, at least in part, the development and progression of childhood GHD in different age groups. With respect to the genetic etiology of isolated GHD (IGHD), mutations in known genes such as those encoding GH (GH1), GHRH receptor (GHRHR), or transcription factors involved in pituitary development, are identified in a relatively small percentage of patients suggesting the involvement of other, yet unidentified, factors. Genome-wide association studies point toward an increasing number of genes involved in the control of growth, but their role in the etiology of IGHD remains unknown. Despite the many years of research in the area of GHD, there are still controversies on the etiology, diagnosis, and management of IGHD in children. Recent data suggest that childhood IGHD may have a wider impact on the health and neurodevelopment of children, but it is yet unknown to what extent treatment with recombinant human GH can reverse this effect. Finally, the safety of recombinant human GH is currently the subject of much debate and research, and it is clear that long-term controlled studies are needed to clarify the consequences of childhood IGHD and the long-term safety of its treatment.

Pros of priming in the diagnosis of growth hormone deficiency

Priming with sex steroids in stimulation tests for the diagnosis of GHD is still under debate. Most of the data on utility of priming during GH stimulation so far seem to support its use in the diagnosis of GHD in childhood. There is a propensity to treat growth retarded children who test subnormally to stimulation tests with GH. However, some studies analyzing the final height or height gain during GH treatment in such children failed to show any improvement in height. This paper summarizes previous studies on priming to analyze the utility of priming as a valid method to better the diagnostic capacity of the test.

Is testosterone and estrogen priming prior to clonidine useful in the evaluation of the growth hormone status of short peripubertal children?

AIM

To determine the usefulness of priming with gonadal steroids prior to growth hormone (GH) stimulation with clonidine in the evaluation of the GH status of short peripubertal children.

CHILDREN AND METHODS

Thirty-nine children, eight females and 31 males, were studied, with a mean chronological age of 12.37 +/- 2.24 years (range 8-15 years), mean bone age 9.58 +/- 2.21 years, Tanner stage 1-2, with height 134.12 +/- 11.27 cm (Ht-SDS -2.24 +/- 0.95), growth velocity (GV) 4.2 cm/yr (GV SDS -2.12 +/- 1.32) and an inadequate response to an initial GH stimulation test with clonidine (peak GH <10 microg/l). A second stimulation test with clonidine was performed in the same patients after gonadal steroid priming: 100 mg i.m. testosterone enanthate 5-8 days prior to GH stimulation in the males, and 1 mg estradiol valerate daily for 3 days in the females. GH, IGF-I, and testosterone/estradiol were measured before and after priming.

RESULTS

Twenty-one of 39 children (53.8%) increased their GH response to a level of >10 microg/l following priming with gonadal steroids. Mean peak GH after priming was 12.32 +/- 8.7 microg/l compared to a peak GH level of 4.87 +/- 2.72 microg/l prior to gonadal steroid priming (peak GH 17.42 +/- 8.46 microg/l in the responders versus 5.95 +/- 2.76 microg/l in the non-responders). Although a significant increase in GH and IGF-I concentrations was noted following priming, we were unable to find a correlation between IGF-I concentrations and peak GH following priming. IGF-I levels were not different in the responders and non-responders to clonidine following priming. There was no correlation between pubertal staging and testosterone/estradiol concentrations before priming with the peak GH after priming.

CONCLUSIONS

Priming with gonadal steroids significantly improves GH secretion following GH stimulation with clonidine and diminishes the possibility of a false diagnosis of GH deficiency. Gonadal steroid priming should therefore be considered in the evaluation of the GH status of short children close to or during the early stages of puberty.

A boy with "transient" growth hormone deficiency in prepubertal stage despite normal growth hormone secretion in childhood and after puberty

Transient growth hormone deficiency (GHD) is occasionally found in prepubertal individuals, and this phenomenon has been variously interpreted. Sex steroids enhance GH secretion; however, the cut-off values of provocative GH tests are not modified according to the physiological changes. Physiological changes in sex steroid levels are thought to cause the image of transient GHD. In addition, the reproducibility of provocative GH tests makes the interpretation complicated. We experienced a case of a boy with short stature who had undergone provocative GH tests at three different times: childhood (5 and 7 years old), before puberty (12 years old), and in adolescence (15 years old). Although the responses of GH in his childhood and adolescence were within the normal range, his prepubertal GH response was extremely low, as if he had "complete" GHD (peak GH: insulin test, 0.60 ng/ml; clonidine test, 0.78 ng/ml). No morphological changes were observed in the pituitary gland or hypothalamus on MRI. The level of insulin-like growth factor 1 was in the normal range for his age at this time. Here, we report the clinical course and endocrinological data of this case, and suggest that transient GHD is caused not only by the physiological effects of sex steroids but also by certain mechanisms that actively reduce GH secretion.