Trends of correlations between serum levels of growth hormone and insulin-like growth factor-I in general practice

Serum levels of growth hormone (GH) and insulin-like growth factor (IGF)-I are crucial in the diagnosis and management of GH-related diseases. However, these levels are affected by nutritional and metabolic status. To elucidate the correlations between GH and IGF-I in various conditions, a retrospective analysis was performed for adult patients in which GH levels were examined by general practitioners during the period from January 2019 to December 2021. Of 642 patients, 33 patients were diagnosed with acromegaly, 21 were diagnosed with GH deficiency (GHD), and 588 were diagnosed with non-GH-related diseases (NGRD). In contrast to the positive correlations found between the levels of GH and IGF-I in patients with acromegaly (R=0.50; P<0.001) and patients with GHD (R=0.39; P=0.08), a negative correlation was found in the NGRD group (R=-0.23; P<0.001). In that group, the results of multivariable analysis showed that GH levels were predominantly influenced by gender and body mass index (BMI), whereas IGF-I levels were modulated by albumin in addition to age and GH. Of note, in the NGRD group, there was an enhanced negative correlation between GH and IGF-I under conditions of BMI < 22 and albumin < 4.0 g/dL (R=-0.45; P<0.001), and the negative correlation between GH and IGF-I was reinforced by excluding patients with other pituitary diseases and patients taking oral steroids (R=-0.51; P<0.001 and R=-0.59; P<0.001, respectively). Collectively, the results indicate that attention should be given to the presence of a negative correlation between serum levels of GH and IGF-I, especially in lean and low-nutritious conditions.

Pituitary Stalk Interruption Syndrome: Analysis of Response to Growth Hormone Therapy

OBJECTIVE

To analyse the clinical and radiological characteristics of pituitary stalk interruption syndrome (PSIS).

METHODS

A retrospective analysis of confirmed cases of PSIS was performed. The development of new pituitary hormonal deficiencies and response to recombinant human growth hormone (rhGH) therapy were assessed during follow-up.

RESULTS

This study included 14 children (10 boys) of PSIS with median (range) age of 12.15 years (2 months - 18 years). Short stature was the most common presentation (n = 13), and micropenis (n = 4), cleft lip (n = 1) and single central incisor (n = 1) were other midline defects. Growth hormone (GH) deficiency was present in 14 children and 7 of them also had multiple pituitary hormone deficiencies at baseline. Central hypothyroidism (n = 5), secondary adrenal deficiency (n = 4) and gonadotropin deficiencies (n = 2) were also seen. All children received rhGH. The mean height gain on follow-up was 12.78 cm in first year (n = 14), 6.5 cm in second year (n = 8) and 4.07 cm in third year (n = 7) of rhGH therapy. Four children developed additional pituitary hormone deficiency on follow-up.

CONCLUSION

Short stature with isolated GH deficiency was the most common presentation of PSIS that showed good response to rhGH therapy.

Beyond Growth Hormone: Association of Short Stature Types and Growth Hormones With Scoliosis

STUDY DESIGN

Cross-sectional and retrospective cohort study.

OBJECTIVE

We investigated the effect of 3 types of short stature [partial growth hormone deficiency (GHD), GHD, and idiopathic short stature (ISS)] and recombinant human growth hormone (rhGH) therapy on scoliosis.

SUMMARY OF BACKGROUND DATA

In short stature, rhGH is widely used and the concentration of growth hormone varies among types. The epidemiologic characteristics of scoliosis and the role of rhGH in scoliosis remain unclear.

PATIENTS AND METHODS

A cross-sectional study was conducted among 3896 patients with short stature (partial GHD, GHD, and ISS), and a 1:1 age and sex-matched control group with preexisting whole-spine radiographs. The cohort study included 2605 subjects who underwent radiography more than twice to assess scoliosis development, progression, and the need for bracing and surgery. Adjusted logistic regression was used to assess differences in the prevalence of scoliosis among patients with partial GHD, GHD, ISS, and controls. The Kaplan-Meier method was used to analyze the time course of scoliosis development and progression. Cox regression was applied to assess the independent factors related to scoliosis development and progression. Mendelian randomization analyses were also performed.

RESULTS

Compared with controls, patients with short stature had a higher incidence of scoliosis (34.47% in partial GHD, 31.85% in GHD, 32.94% in ISS vs . 8.83% in control, P < 0.001), a higher risk of scoliosis development [hazard ratio (HR) = 1.964 in partial GHD, P < 0.001; HR = 1.881 in GHD, P = 0.001; HR = 1.706 in ISS, P = 0.001), but not a higher risk of progression, brace, or surgery. Among the 3 types of short stature, there were no differences in the incidence, development, and progression of scoliosis or the need for bracing or surgery. RhGH treatment increased the risk of scoliosis development in each short-stature group (HR = 2.673 in partial GHD, P < 0.001; HR = 1.924 in GHD, P = 0.049; HR = 1.564 in ISS, P = 0.004). Vitamin D supplementation was protective against scoliosis development (HR = 0.456 in partial GHD, P = 0.003; HR = 0.42 in GHD, P = 0.013; HR = 0.838 in ISS, P = 0.257).

CONCLUSIONS

More attention should be paid to the spinal curve in patients with partial GHD, GHD, or ISS. For short stature treated with rhGH, the risk of scoliosis development was increased. Vitamin D supplementation may be beneficial for prevention.

LEVEL OF EVIDENCE

Level III.

Insights from an advisory board: Facilitating transition of care into adulthood in brain cancer survivors with acquired pediatric growth hormone deficiency

OBJECTIVE

Children with growth hormone deficiency (GHD) face multiple challenges that can negatively impact the transition from pediatric to adult endocrinology care. For children with GHD resulting from brain cancer or its treatment, the involvement of oncology care providers and possible disease-related comorbidities add further complexity to this transition.

DESIGN

An advisory board of pediatric and adult endocrinologists was convened to help better understand the unique challenges faced by childhood cancer survivors with GHD, and discuss recommendations to optimize continuity of care as these patients proceed to adulthood. Topics included the benefits and risks of growth hormone (GH) therapy in cancer survivors, the importance of initiating GH replacement therapy early in the patient's journey and continuing into adulthood, and the obstacles that can limit an effective transition to adult care for these patients.

RESULTS/CONCLUSIONS

Some identified obstacles included the need to prioritize cancer treatment over treatment for GHD, a lack of patient and oncologist knowledge about the full range of benefits provided by long-term GH administration, concerns about tumor recurrence risk in cancer survivors receiving GH treatment, and suboptimal communication and coordination (e.g., referrals) between care providers, all of which could potentially result in treatment gaps or even complete loss of follow-up during the care transition. Advisors provided recommendations for increasing education for patients and care providers and improving coordination between treatment team members, both of which are intended to help improve continuity of care to maximize the health benefits of GH administration during the critical period when childhood cancer survivors transition into adulthood.

Evaluation of growth hormone deficiency in women with unexplained infertility

PURPOSE

Growth hormone (GH) has been recognized to play a regulatory role in female reproduction. It has been reported that infertile GH deficient patients regained fertility after GH replacement. The frequency of GH deficiency is not established in patients diagnosed with unexplained infertility. Here, we aim to present the prevalence of GH deficieny in this patient group.

METHODS

We included patients diagnosed with unexplained infertility throughout 18 months. Insulin tolerance test (ITT) and glucagon stimulation tests (GST) were performed and insufficient response to both tests was required for the diagnosis of GH deficiency.

RESULTS

Twenty-five patients were included in the study, the mean age was 27.4 ± 4.5 years and the median duration of infertility was 60 months (min:14, max:120). Two patients were GH deficient according to GST and 14 to ITT. Two patients (8%) showed lack of response on both tests and were diagnosed with GH deficiency.

CONCLUSION

The rate of GH deficiency among women with unexplained infertility was 8% in this preliminary study. There is need for further studies with larger patient groups to verify the results.

Nonalcoholic fatty liver disease and adult growth hormone deficiency: An under-recognized association?

Growth hormone (GH) plays an essential role not only in promoting growth in children, but also in many important metabolic processes in adults. One of the major metabolic functions of GH is its stimulatory effects on the liver in generating approximately 80% of circulating insulin-like growth factor 1 (IGF-1). Adult growth hormone deficiency (GHD) is an established clinical entity defined as a defect in endogenous GH secretion that is frequently associated with central obesity, loss of muscle mass, decreased bone mass, and impaired quality of life. Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are conditions that are often under-recognized in adults with GHD, and accordingly some studies have shown that GH and IGF-1 levels are decreased in patients with NAFLD. Furthermore, it has been reported that it can progress to end-stage liver cirrhosis in some adults and children with GHD. Due to their underlying mechanisms of action, GH and IGF-1 can act on hepatocytes, macrophages, and hepatic stellate cells to mitigate progression to steatosis and fibrosis. It is, thus, important to recognize NAFLD/NASH as important complications in adult and childhood GHD. Therefore, careful and thorough evaluation of NAFLD/NASH in adults with GHD and the consideration for GH replacement therapy is crucial in these patients, together with management of other metabolic risk factors, such as obesity and dyslipidemia. This review will focus on recent reports on the role of GH and IGF-1 in the liver and its clinical significance in the regulation of hepatic function.

Mild traumatic brain injury as a cause of adult growth hormone deficiency: Diagnosis and treatment

In recent years, mild traumatic brain injury (mTBI) has been recognized as a cause of acquired growth hormone deficiency (AGHD) and is likely much more prevalent than previous estimates. There is great overlap between persistent symptoms following mTBI and those of AGHD and it is possible that these persistent symptoms of mTBI are, at least in part, due to or aggravated by AGHD. This article reviews the current literature of AGHD following mTBI, and proposes practice recommendations for the screening, diagnosis, and management of patients with AGHD following mTBI.

A Novel Heterozygous NF1 Variant in a Neurofibromatosis-Noonan Syndrome Patient with Growth Hormone Deficiency: A Case Report

Neurofibromatosis-Noonan syndrome (NFNS), a rare autosomal-dominant hereditary disease, is characterized by clinical manifestations of both neurofibromatosis type 1 (NF1) and NS. We present a case of NFNS with short stature caused by a heterozygous nonsense variant of the NF1 gene. A 12-year-old boy was admitted because of short stature, numerous café-au-lait spots, low-set and posteriorly rotated ears, sparse eyebrows, broad forehead, and inverted triangular face. Cranial and spinal magnetic resonance imaging showed abnormal nodular lesions. Molecular analysis revealed a novel heterozygous c.6189 C > G (p.(Tyr2063*)) variant in the NF1 gene. The patient was not prescribed recombinant growth hormone (GH) therapy because exogenous GH may have enlarged the abnormal skeletal lesions. During follow-up, Lisch nodules were found in the ophthalmologic examination. NFNS, a variant form of NF1, is caused by heterozygous mutations in the NF1 gene. The mechanism of GH deficiency caused by NF1 is still unclear. Whether NFNS patients should be treated with exogenous GH remains controversial.

A Novel Pathogenic IGSF1 Variant in a Patient with GH and TSH Deficiency Diagnosed by High IGF-I Values at Transition to Adult Care

IGSF1 deficiency is a rare X-linked condition characterized by central hypothyroidism and a wide variety of other clinical features with variable prevalence, including a delayed pubertal testosterone rise and growth spurt in the context of normal or accelerated testicular growth, and adult macroorchidism with relatively low serum testosterone concentrations. Other features include increased waist circumference, attention deficit, prolactin deficiency and transient partial growth hormone (GH) deficiency in childhood, contrasting with an increased GH secretion in adulthood. Patients with this disorder are not detected shortly after birth if neonatal screening programs are based on thyroid-stimulating hormone (TSH) concentrations. A 13.2-year-old male patient was referred to pediatric endocrinology for evaluation of short stature. He was born large for gestational age into a nonconsanguineous family. During work-up for short stature, deficiencies of TSH, prolactin and GH were detected, leading to treatment with levothyroxine and GH. At 16.9 years, GH treatment was stopped and during transition to adult care, his insulin-like growth factor 1 level was above the normal range. This prompted an analysis of IGSF1, in which a novel hemizygous variant causing a stop codon at c.3559C>T (p.Q1187*) was found, confirming the diagnosis of IGSF1 deficiency syndrome. In this report, we describe his clinical and hormonal characteristics at presentation and during long-term follow-up.

GHRH + arginine test and body mass index: do we need to review diagnostic criteria for GH deficiency?

INTRODUCTION

The proportion of patients with low GH response to provocative tests increases with the number of other pituitary hormone deficiencies, reason why in panhypopituitary patients GH stimulation tests may be unnecessary to diagnose GH deficiency (GHD) PURPOSE: To re-evaluate the diagnostic cut-offs of GH response to GHRH + arginine (ARG) test related to BMI, considering the patients' pituitary function as the gold standard for the diagnosis of GHD.

METHODS

The GH responses to GHRH + ARG were studied in 358 patients with history of hypothalamic-pituitary disease. GHD was defined by the presence of at least 3 other pituitary deficits (n = 223), while a preserved somatotropic function was defined by the lack of other pituitary deficits and an IGF-I SDS ≥ 0 (n = 135). The cut-off with the best sensitivity (SE) and specificity (SP), was identified for each BMI category using the ROC curve analysis. To avoid over-diagnosis of GHD we subsequently searched for the cut-offs with a SP ≥ 95%.

RESULTS

The best GH cut-off was 8.0 μg/l (SE 95%, SP 100%) in lean, 7.0 μg/l (SE 97.3%, SP 82.8%) in overweight, and 2.8 μg/l (SE 84.3%, SP 91.7%) in obese subjects. The cut-off with a SP ≥ 95% was 2.6 μg/l (SE 68.5%, SP 96.6%) in overweight and 1.75 μg/l (SE 70.0%, SP 97.2%) in obese subjects.

CONCLUSIONS

This is the first study that evaluates the diagnostic cut-offs of GH response to GHRH + ARG related to BMI using a clinical definition of GHD as gold standard. Our results suggest that with this new approach, the GHRH + ARG cut-offs should be revised to avoid GHD over-diagnosis.

Recombinant growth hormone improves growth and adult height in patients with maternal inactivating GNAS mutations

BACKGROUND

Maternal inactivating GNAS mutations lead to pseudohypoparathyroidism 1A (PHP1A), newly classified as inactivating parathyroid hormone (PTH)/PTHrP-signaling disorder type 2 of maternal inheritance (iPPSD2). Patients present with resistance to PTH and other hormones, subcutaneous ossifications, brachydactyly, short stature, and early-onset obesity. They can be born small for gestational age (SGA) and may present with growth hormone (GH) deficiency. The use of recombinant human GH (rhGH) therapy has been sporadically reported, yet we lack data on the long-term efficacy and safety of rhGH, as well as on adult height.

OBJECTIVE

Our multicenter, retrospective, observational study describes growth in patients treated with rhGH in comparison with untreated iPPSD2/PHP1A controls.

METHODS

We included 190 patients, of whom 26 received rhGH. Height, weight, body mass index at various time points, and adult height were documented. We analyzed the effect of rhGH on adult height by using linear mixed models.

RESULTS

Adult height was available for 11/26 rhGH-treated individuals and for 69/164 controls. Patients treated with rhGH showed a gain in height of 0.7 standard deviation scores (SDS) after 1 year (CI +0.5 to +0.8, P < .001) and of 1.5 SDS after 3 years (CI +1.0 to +2.0, P < .001). Additionally, there was a clear beneficial impact of rhGH on adult height when compared with untreated controls, with a difference of 1.9 SDS (CI +1.1 to +2.7, P < .001). Body mass index SDS did not vary significantly upon rhGH therapy.

CONCLUSION

Recombinant human growth hormone treatment of iPPSD2/PHP1A patients with short stature improves growth and adult height. More studies are needed to confirm long-term efficacy and safety.

Vascular Function and Intima-Media Thickness in Children and Adolescents with Growth Hormone Deficiency: Results from a Prospective Case-Control Study

INTRODUCTION

Growth hormone deficiency (GHD) may be associated with subtle cardiovascular abnormalities, reversible upon starting GH treatment. Data on vascular morphology and function in GHD children are scanty and inconclusive. The aim of our study was to evaluate the effects of GHD and GH treatment on endothelial function and intima-media thickness (IMT) in children and adolescents.

METHODS

We enrolled 24 children with GHD (10.85 ± 2.71 years) and 24 age-, sex-, and BMI-matched controls. We evaluated anthropometry, lipid profile, asymmetric dimethylarginine (ADMA), brachial flow-mediated dilatation (FMD), and IMT of common (cIMT) and internal (iIMT) carotid artery at study entry in all subjects and after 12 months of treatment in GHD children.

RESULTS

At baseline GHD, children had higher total cholesterol (163.17 ± 18.66 vs. 149.83 ± 20.68 mg/dL, p = 0.03), LDL cholesterol (91.18 ± 20.41 vs. 77.08 ± 19.73 mg/dL, p = 0.019), atherogenic index (AI) (2.94 ± 0.71 vs. 2.56 ± 0.4, p = 0.028), and ADMA (215.87 ± 109.15 vs. 164.10 ± 49.15 ng/mL, p < 0.001), compared to controls. GHD patients also exhibited increased higher waist-to-height ratio (WHtR) compared to controls (0.48 ± 0.05 vs. 0.45 ± 0.02 cm, p = 0.03). GH therapy resulted in a decrease in WHtR (0.44 ± 0.03 cm, p = 0.001), total (151.60 ± 15.23 mg/dL, p = 0.001) and LDL cholesterol (69.94 ± 14.40 mg/dL, p < 0.0001), AI (2.28 ± 0.35, p = 0.001), and ADMA (148.47 ± 102.43 ng/mL, p < 0.0001). GHD showed lower baseline FMD than controls (8.75 ± 2.44 vs. 11.85 ± 5.98%, p = 0.001), which improved after 1-year GH treatment (10.60 ± 1.69%, p = 0.001). Baseline cIMT and iIMT were comparable between the two groups, but slightly reduced in GHD patients after treatment.

CONCLUSION

GHD children may exhibit endothelial dysfunction in addition to other early atherosclerotic markers like visceral adiposity, and altered lipids, which can be restored by GH treatment.

Evaluating the TUITEK® patient support program in supporting caregivers of children diagnosed with growth hormone deficiency in Argentina

Introduction

The appropriate use of recombinant human growth hormone (r-hGH) treatment provides an opportunity to improve growth outcomes among pediatric patients with growth hormone deficiency (GHD). However, a major challenge in clinical practice is to adequately recognize and address factors that negatively affect treatment adherence. TUITEK® patient support program (PSP) was designed to help caregivers of children diagnosed with GHD to personalize the care pathway, improve adherence, and achieve better outcomes. Effectiveness of TUITEK® PSP has been demonstrated previously in a smaller sample (n = 31) in Taiwanese population. Here, we present the results from Argentina.

Methods

TUITEK® PSP was piloted among 76 caregivers of children with GHD administering r-hGH using easypod™ (Merck KGaA, Darmstadt, Germany) auto-injector device in Argentina. Based on TUITEK® personalization questionnaire, caregivers were assigned to high- and low-risk groups across four categories that may influence adherence, including disease and treatment coherence (DTC), self-administration (SA), treatment-related anxiety (TRA), and emotional burden (EB). The caregivers who were included in atleast one high-risk group had the provision of telephone calls with a nurse practitioner every 2 weeks for 3 months. The Wilcoxon signed-rank test was employed to assess changes in questionnaire-based scoring patterns between baseline and follow-up evaluations.

Results

Statistically significant changes (p &lt; 0.05) in questionnaire scores between baseline and follow-up evaluations were observed across the four categories. The mean/median DTC (n = 11) and SA (n = 23) scores changed from 2.45/3 and 2.17/2, respectively, to 4/4, with all the caregivers moving to low-risk group following program completion (100%) for both categories. The mean/median TRA score (n = 40) changed from 3.58/3 to 2.5/2 and 67.5% of patients (27/40) moved to low-risk group. The mean/median EB score (n = 32) changed from 3.69/3 to 3.13/3 however, none of the caregivers moved to low-risk group (0%).

Conclusion

TUITEK® PSP is a simple, practical, and time-efficient interventional tool that can be used to address key adherence-related issues among caregivers of children with GHD and provide personalized adherence support. Our findings demonstrate that TUITEK® PSP has the potential to improve treatment adherence and self-management, thereby improving growth outcomes in Argentina.

Serum IGF-1 to IGFBP-3 Molar Ratio: A Promising Diagnostic Tool for Growth Hormone Deficiency in Children

BACKGROUND

The serum insulin-like growth factor-1 (IGF-1)/insulin-like growth factor binding protein-3 (IGFBP-3) ratio has various potential applications in growth hormone-related disorders. This study aimed to investigate the performance of the IGF-1/IGFBP-3 ratio, independently and in combination with serum IGF-1 and IGFBP-3, in the diagnosis of growth hormone deficiency (GHD) in children with short stature (SS).

METHODS

A 7-year cross-sectional observational study was conducted on 235 children with SS. Participants with known disorders that may affect IGF-1 other than GHD were excluded. Participants were classified into GHD (n = 64) and non-GHD (n = 171) groups. GHD was defined as a slow growth rate (<25th percentile over 1 year) and suboptimal growth hormone (GH) response to 2 GH stimulation tests (peak GH < 6.25 ng/mL using the DiaSorin Liaison assay). The sensitivity and specificity of serum IGF-1, IGFBP-3, and IGF-1/IGFBP-3 molar ratio, independently and in various combinations, were determined.

RESULTS

GHD was diagnosed in 27.2% of participants. Among all studied variables, a low serum IGF-1/IGFBP-3 ratio demonstrated the greatest sensitivity for GHD (87.5%), with a comparable specificity (83.0%). The combination of low serum IGF-1, IGFBP-3, and IGF-1/IGFBP-3 ratio demonstrated the greatest specificity for GHD (97.7%), whereas the combination of normal serum IGF-1, IGFBP-3, and IGF-1/IGFBP-3 ratio demonstrated the greatest specificity for a non-GHD cause of SS (100.0%).

CONCLUSION

Our data suggest that the serum IGF-1/IGFBP-3 ratio is a useful marker for the diagnosis of GHD in children who do not have other disorders that may affect serum IGF-1 levels. Further large studies are needed to confirm the diagnostic utility of the serum IGF-1/IGFBP-3 ratio.

Preliminary study of longitudinal changes in the pituitary and brain of children on growth hormone therapy

BACKGROUND

In subjects with isolated growth hormone deficiency (IGHD), recombinant human growth hormone (rhGH) is an approved method to achieve potential mid-parental height. However, data reporting rhGH treatment response in terms of brain structure volumes were scarce. We report the volumetric changes of the pituitary gland, basal ganglia, corpus callosum, thalamus, hippocampus and amygdala in these subjects post rhGH treatment.

MATERIALS AND METHODS

This was a longitudinal study of eight IGHD subjects (2 males, 6 females) with a mean age of 11.1 ± 0.8 years and age-matched control groups. The pituitary gland, basal ganglia and limbic structures volumes were obtained using 3T MRI voxel-based morphology. The left-hand bone age was assessed using the Tanner-Whitehouse method. Follow-up imaging was performed after an average of 1.8 ± 0.4 years on rhGH.

RESULTS

Subjects with IGHD had a smaller mean volume of the pituitary gland, right thalamus, hippocampus, and amygdala than the controls. After rhGH therapy, these volumes normalized to the age-matched controls. Corpus callosum of IGHD subjects had a larger mean volume than the controls and did not show much volume changes in response to rhGH therapy. There were changes towards normalization of bone age deficit of IGHD in response to rhGH therapy.

CONCLUSION

The pituitary gland, hippocampus, and amygdala volumes in IGHD subjects were smaller than age-matched controls and showed the most response to rhGH therapy. Semi-automated volumetric assessment of pituitary gland, hippocampus, and amygdala using MRI may provide an objective assessment of response to rhGH therapy.

Relationship Between the Serum FGF21 Level and Growth in Children of Short Stature

BACKGROUND

This study investigated the relationship between fibroblast growth factor 21 (FGF21) levels and growth in children with growth hormone deficiency (GHD) and idiopathic short stature (ISS), and the effects of the FGF21 level on response to growth hormone (GH) treatment.

METHODS

We included 171 pre-pubertal children with a GHD (n = 54), ISS (n = 46), and normal height (n = 71). Fasting FGF21 levels were measured at baseline and every 6 months during GH treatment. Factors associated with growth velocity (GV) after GH therapy were investigated.

RESULTS

The FGF21 level was higher in short children than in the controls without significant difference between the GHD and ISS groups. In the GHD group, the FGF21 level was inversely associated with the free fatty acid (FFA) level at baseline (r = -0.28, P = 0.039), however, was positively correlated with the FFA level at 12 months (r = 0.62, P = 0.016). The GV over 12 months of GH therapy was positively associated with the delta insulin-like growth factor 1 level (β = 0.003, P = 0.020). The baseline log-transformed FGF21 level was inversely associated with GV with marginal significance (β = -0.64, P = 0.070).

CONCLUSION

The FGF21 level was higher in children of short stature, both those with GHD and the ISS, than in children with normal growth. The pretreatment FGF21 level negatively affected the GV of children with GH-treated GHD. These results suggest the existence of a GH/FFA/FGF21 axis in children.

Short stature in PRMT7 Mutations: first evidence of response to growth hormone treatment

Protein arginine methyltransferase 7 (PRMT7) pathogenetic variants have been associated with the human disorder of Short Stature, Brachydactyly, Intellectual Developmental Disability and Seizures syndrome (SBIDDS). Only 15 cases have been described in the literature. Here we report two female dizygotic twins with novel compound heterozygous deleterious variants of PRMT7 and describe the associated endocrine manifestations and short-term response to recombinant growth hormone (rGH) treatment. They were born at 36 + 3 weeks from a dichorionic diamniotic twin pregnancy. Twin A was appropriate for gestational age while Twin B was small for gestational age. Whole exome sequencing analyses showed the same novel compound heterozygous genetic defects in the PRMT7 gene (c.1220 G > A of maternal origin; c.1323 + 2 T > G of paternal origin, Fig. 1). Due to severe short stature and growth impairment, at six years of age, endocrine investigations were performed to rule out growth hormone (GH) deficiency, and revealed GH deficiency (GHD) in Twin A and an appropriate GH response in Twin B. Therefore, both started rGH, albeit at different dosages according to the underlying diagnosis. Both showed a satisfactory short-term response to treatment with height gain (∆HT) of +0.52 SDS (Twin A) and +0.88 SDS (Twin B) during the first year. In conclusion, our findings expand the knowledge about the endocrine manifestations associated with PRMT7 pathogenetic variants, including GH deficiency and rGH response. Further studies are needed to investigate long-term outcomes and establish whether PRMT7 genetic defects can be included among syndromic short stature treatable with rGH.

Caregiving burden and special needs of parents in the care of their short-statured children - a qualitative approach

PURPOSE

To explore caregiving burden, health-related quality of life (HRQOL), stress, and individual resources of parents in the care of children with isolated growth hormone deficiency (IGHD) or idiopathic short stature (ISS).

METHODS

Focused interview analysis of previously, within the Quality of Life in Short Stature Youth (QoLISSY) project, conducted structured focus group discussions (n=7) with parents (n=33) of children with IGHD/ISS aged 4 to 18 years were performed.

RESULTS

26 out of the 33 parents reported mental stress due to their child's growth disorder. Social pressure and stigmatization were also mentioned as being demanding. Some parents reported having trouble with human growth hormone (hGH) treatment. Several parents wished for parent support groups with other like-minded parents of short-statured children.

CONCLUSION

For physicians, it is essential to understand the parents' caregiving burden, stress, and individual resources in caring for IGHD/ISS children. If an impaired HRQOL is detected, psychological intervention for these parents may be scheduled, and coping mechanisms may be discussed. Furthermore, it seems essential for parents to be educated by their healthcare provider about the possible side effects of hGH treatment or to know where to find evidence-based information about it.

The influence of growth hormone on pediatric body composition: A systematic review

BACKGROUND

Growth hormone (GH) affects metabolism and regulates growth in childhood. The most prominent feature of GH deficiency (GHD) in children is diminished height velocity that eventually leads to short stature. In adult-onset GHD, lean body mass (LBM) is reduced, and visceral fat mass (FM) increased. Beneficial effects of GH treatment on body composition in adults with GHD, including an increase in muscle mass and a decrease in FM, are well established. Relatively few studies have investigated the effects of GH treatment on the body composition of pediatric patients with idiopathic or hypothalamic-pituitary disease-associated GH deficiency. This systematic review aimed to summarize available evidence relating to the effects of GH treatment on body composition in children with GHD.

METHODS

The PubMed, Science Direct, Cochrane Trials, and Embase databases, were searched with keywords including "GH", "body composition", "children", and "growth hormone" for English-language articles, published between January 1999 and March 2021. Two reviewers independently evaluated the search results and identified studies for inclusion based on the following criteria: participants had a confirmed diagnosis of GHD (as defined in each study); participants were pediatric patients who were receiving GH or had stopped GH treatment, regardless of whether they were pre- or post-pubertal; the intervention was recombinant human GH (rhGH; somatropin); and outcomes included changes in body composition during or after stopping GH therapy. Data extracted from each study included study quality, study sample characteristics, study interventions, and body composition. Data on fat-free mass and LBM were combined into a single category of LBM.

RESULTS

Sixteen studies reporting changes in body composition (i.e., FM and LBM) associated with GH treatment in children with GHD were identified and included in the review. Collectively, these studies demonstrated that FM decreased, and LBM increased in response to GH replacement therapy.

CONCLUSION

Despite study limitations (i.e., potential effects of diet and physical activity were not considered), we concluded that a periodic body composition assessment is required to ensure that a satisfactory body composition is achieved during GH replacement therapy in children with GHD.

Safety and Efficacy of Pediatric Growth Hormone Therapy: Results From the Full KIGS Cohort

CONTEXT

The Kabi/Pfizer International Growth Database (KIGS) is a large, international database (1987-2012) of children treated with recombinant human growth hormone (rhGH) in real-world settings.

OBJECTIVE

This work aimed to evaluate the safety and efficacy of rhGH from the full KIGS cohort.

METHODS

Data were collected by investigators from children with growth disorders treated with rhGH (Genotropin [somatropin]; Pfizer). Safety was evaluated in all treated patients, and efficacy in those treated for 1 year or more. A subgroup included patients treated for 5 years or more (≥ 2 years prepubertal) who had reached near-adult height (NAH). Main outcomes included adverse events (AEs), serious AEs (SAEs), and height growth.

RESULTS

The full KIGS cohort (N = 83 803 [58% male]) was treated for idiopathic GH deficiency (IGHD; 46.9%), organic GHD (10.0%), small for gestational age (SGA; 9.5%), Turner syndrome (TS; 9.2%), idiopathic short stature (ISS; 8.2%), and others (16.2%). Median rhGH treatment duration was 2.7 years and observation 3.1 years. SAEs occurred in 3.7% of patients and death in 0.4%. The most common SAEs were recurrence of craniopharyngioma (n = 151), neoplasm (n = 99), and cancer (n = 91); and scoliosis (n = 91). Median first-year delta height-SD score (SDS) (Prader) in prepubertal patients was 0.66 (IGHD), 0.55 (ISS), 0.58 (TS), and 0.71 (SGA). Median gains in NAH-SDS were 1.79 (IGHD), 1.37 (ISS), and 1.34 (SGA) for boys, and 2.07 (IGHD), 1.62 (ISS), 1.07 (TS), and 1.57 (SGA) for girls.

CONCLUSION

Data from KIGS, the largest and longest running international database of rhGH-treated children, show that rhGH is safe and increases short-term height gain and adult height across GHD and non-GHD conditions.

COMPARISON OF BONE MATURATION RESPONSE TO TREATMENT WITH SHORT AND LONG-TERM GROWTH HORMONE THERAPY IN SHORT-STATURE PEDIATRIC PATIENTS

Growth hormone deficiency is one of the major causes of short stature in children. It has been noted that hormonal treatment can be vindicated in short-stature children unless there are contraindications. This study aimed to investigate the impact of rhGH therapy duration on the increase of subjects' height at the end of therapy. Materials and methods: A retrospective longitudinal study of children diagnosed with short stature was followed. Participants aged between 5 and 15 years old who had their GH stimulation test done were included in the study. Collected data were patients' age, gender, rhGH therapy duration and height (cm) at presentation and the end of therapy. GH stimulation test readings and bone age were also gathered. Results: 129 children aged between 5-15 years of both gender were included in the study. They were grouped into three groups according to the duration of the received GH therapy: an 8-month group (n=25), a 14-month group (n=59) and 22-month group (n=45). No significant difference between males and females in regards to bone age, but the readings significantly increased with the increase in therapy duration (p<0.05). Growth hormone assay results were conversely reduced with the increase in GH therapy duration, with no significant difference between the two genders. Interestingly, an increase in the participant's height in the three treatment groups both males and females were reported. Overall, the increase in height was 7.08 cm, 12.58 cm and 20.84 cm in 8, 14 and 22-month groups (± 1.6, 3.3 and 4.3), respectively, a significant statistical difference between the three groups (p-value <0.05). This study provides evidence of the effect of long-term 22-month rhGH therapy on bone age and body height both in male and female children. Further prospective studies are required to assess the effect of the GH stimulation test on GH therapy.

Decreased lifespan in female "Munchkin" actors from the cast of the 1939 film version of The Wizard of Oz does not support the hypothesis linking hypopituitary dwarfism to longevity

In laboratory mice, pituitary dwarfism caused by genetic reduction or elimination of the activity of growth hormone (GH) significantly extends lifespan. The effects of congenital pituitary dwarfism on human longevity are not well documented. To analyse the effects of untreated pituitary dwarfism on human lifespan, the longevity of a diverse group of widely known little people, the 124 adults who played "Munchkins" in the 1939 movie The Wizard of Oz was investigated. Survival of "Munchkin" actors with those of controls defined as cast members of The Wizard of Oz and those of other contemporary Academy Award winning Hollywood movies was compared. According to the Kaplan-Meier survival curves, survival of female and male "Munchkin" actors was shorter than cast controls and Hollywood controls of respective sexes. Cox regression analyses showed that female "Munchkin" actors had significantly higher risk ratios compared to both female cast controls (RR, 1.70; 95% CI, 1.05 to 2.77) and female Hollywood controls (RR, 1.52; 95% CI, 1.03 to 2.24). Similar trends were also discernible for men, albeit point estimates were not significant. The lack of lifespan extension in "Munchkin" actors does not support the hypothesis that hereditary GH deficiency regulates longevity in humans.

A consensus on optimization of care in patients with growth hormone deficiency and mild traumatic brain injury

OBJECTIVE/DESIGN

Approximately 2.9 million children and adults in the US experience traumatic brain injuries (TBIs) annually, most of which are considered mild. TBI can induce varying consequences on pituitary function, with growth hormone deficiency (GHD) among the more commonly reported conditions. Panels of pediatric and adult endocrinologists, neurologists, physical medicine and rehabilitation specialists, and neuropsychologists convened in February and October 2020 to discuss ongoing challenges and provide strategies for detection and optimal management of patients with mild TBI and GHD.

RESULTS

Difficulties include a low rate of seeking medical attention in the population, suboptimal screening tools, cost and complexity of GHD testing, and a lack of consensus regarding when to test or retest for GHD. Additionally, referrals to endocrinologists from other specialists are uncommon. Recommendations from the panels for managing such patients included multidisciplinary guidelines on the diagnosis and management of post-TBI GHD and additional education on long-term metabolic and probable cognitive benefits of GH replacement therapy.

CONCLUSION

As patients of all ages with mild TBI may develop GHD and/or other pituitary deficiencies, a multidisciplinary approach to provide education to endocrinologists, neurologists, neurosurgeons, traumatologists, and other providers and guidelines for the early identification and management of persistent mild TBI-related GHD are urgently needed.

Pituitary function and the response to GH therapy in patients with Langerhans cell histiocytosis: analysis of the KIMS database

OBJECTIVE

To analyze the effectiveness and safety of growth hormone (GH) replacement treatment in adult patients with Langerhans cell histiocytosis (LCH) and GH deficiency (GHD) enrolled in KIMS (Pfizer International Metabolic Database).

PATIENTS AND METHODS

Patients with LCH and GHD were studied at baseline and some of them after 1 year of GH treatment. The effectiveness of GH is presented as change after 1 year of treatment (mean, 95% CI). The LCH population was compared to two other groups of patients enrolled in KIMS, granulomatous and lymphocytic hypophysitis.

RESULTS

At baseline, 81 adults with LCH (27 with childhood onset, 56% females), mean age at GHD onset of 29 (15) years were studied. Diabetes insipidus was diagnosed in 86% of patients. Analysis of 1 year of GH treatment was possible in 37 patients. One-year cross-sectional values for the GH dose were 0.39 (s.d.± 0.21) mg and -0.5 (-1.2 to 0.2) for insulin-like growth factor-1 s.d. Total cholesterol decreased 0.9 (-1.5 to -0.3 (mmol/L); P < 0.05); AGHDA-QoL-score (n = 20) was improved by 2.8 points (-5.6 to 0.0; P < 0.05), while mean BMI increased 0.6 ± 3 kg/m2 (95% CI: -0.2 to 1.4). All these effects did not differ from the two other groups after adjusting for age, gender, and baseline values. In 20 of 77 patients included in the safety analysis, 36 serious adverse events were reported during 435 patient-years (82.8/1000); no new safety signals were reported.

CONCLUSION

After 1 year of GH treatment in patients with LCH, metabolic variables and quality of life improved, with no new safety signals.

A Radiomics-Based Model with the Potential to Differentiate Growth Hormone Deficiency and Idiopathic Short Stature on Sella MRI

PURPOSE

We hypothesized that a radiomics approach could be employed to classify children with growth hormone deficiency (GHD) and idiopathic short stature (ISS) on sella magnetic resonance imaging (MRI). Accordingly, we aimed to develop a radiomics prediction model for differentiating GHD from ISS and to evaluate the diagnostic performance thereof.

MATERIALS AND METHODS

Short stature pediatric patients diagnosed with GHD or ISS from March 2011 to July 2020 at our institution were recruited. We enrolled 312 patients (GHD 210, ISS 102) with normal sella MRI and temporally split them into training and test sets (7:3). Pituitary glands were semi-automatically segmented, and 110 radiomic features were extracted from the coronal T2-weighted images. Feature selection and model development were conducted by applying mutual information (MI) and a light gradient boosting machine, respectively. After training, the model's performance was validated in the test set. We calculated mean absolute Shapley values for each of the selected input features using the Shapley additive explanations (SHAP) algorithm. Volumetric comparison was performed for GHD and ISS groups.

RESULTS

Ten radiomic features were selected by MI. The receiver operating characteristics curve of the developed model in the test set was 0.705, with an accuracy of 70.6%. When analyzing SHAP plots, root mean squared values had the highest impact in the model, followed by various texture features. In volumetric analysis, sagittal height showed a significant difference between GHD and ISS groups.

CONCLUSION

Radiomic analysis of sella MRI may be able to differentiate between GHD and ISS in clinical practice for short-statured children.

Demographic characteristics of children with growth hormone deficiency from 1996 to 2015 in Japan: 20 years of data from the foundation for growth science in Japan

Growth hormone (GH) deficiency (GHD) in children is a heterogeneous condition that includes several entities of various severities. GH treatment has been affected by various factors. Because comprehensive analyses for Japanese children with GHD over time are scarce, we investigated the baseline characteristics of patients with GHD at the start of GH treatment between 1996 and 2015 using data from the Foundation for Growth Science in Japan. During the registration period, 19,717 subjects were determined to be eligible for GH treatment as GHD. Overall analyses revealed that there were twice the number of male patients as female patients, and the etiology was idiopathic in 91.1%, central nervous system (CNS) tumor at the hypothalamus-pituitary area in 1.7%, CNS tumor distant from the hypothalamus-pituitary area in 0.68%, other tumors in 0.91%, congenital CNS malformations in 0.83%, and other diseases in 1.1% with their specific characteristics. The latest average age, height standard deviation score (SDS), insulin-like growth factor-1 SDS, and proportion of severe GHD at GH treatment initiation were 8.8 years, -2.76, -1.42, and 19.5%, respectively. The proportions of breech delivery and asphyxia gradually decreased, whereas that of caesarean section gradually increased during the registration period with the latest values of 2.2%, 4.9%, and 14.0%, respectively (all analyses: p < 0.0001). In contrast, the proportion of idiopathic GHD with breech delivery seemed to reach the lowest level among those with a birth year before 2000. This study identified the characteristics and changes of patients with GHD over 20 years.

Can GH Therapy Worsen a Clinically Silent Chiari Malformation? A Case Report and Systematic Literature Review

BACKGROUND

The link between the effects of recombinant human growth hormone (rhGH) therapy in patients with growth hormone deficiency (GHD) and Chiari malformation type I (CM-1) is controversial.

SUMMARY

We report the case of a patient with an unusual association of GHD due to ectopic posterior pituitary and CM-1. Our patient developed a headache and worsening of CM-1 after the initiation of rhGH therapy. Following an atlo-occipital decompression surgery, the patient was able to resume therapy with a marked growth improvement. Based on this observation, we provide a systematic review of the current literature about these two pathologies.

KEY MESSAGES

A careful follow-up of all patients with CM-1 treated with GH is mandatory, paying particular attention to the appearance of any neurological signs and symptoms.

The pharmacokinetic and pharmacodynamic properties and short-term outcome of a novel once-weekly PEGylated recombinant human growth hormone for children with growth hormone deficiency

Objectives

To investigate the pharmacokinetics (PK) and pharmacodynamics (PD) of Y-shape branched PEGylated recombinant human growth hormone (YPEG-rhGH) and evaluate its short-term efficacy and safety in children with growth hormone deficiency (GHD).

Methods

A total of 43 children with GHD from 12 sites in China were enrolled in this randomized, multicenter, active-controlled, double-blind (YPEG-rhGH doses) trial. Patients were randomized 1:1:1:1 to 100, 120, and 140 μg/kg/week of YPEG-rhGH groups and daily rhGH 35 μg/kg/day groups. The treatment lasted 12 weeks. The primary outcome was the area under the curve of the change of insulin-like growth factor-1 (IGF-1). The secondary outcome was the height velocity (HV) increment at week 12.

Results

A dose-dependent response of maximum plasma concentration (Cmax) and area under the concentration-time curves from 0 to 168 hours (AUC0-168h) were observed for YPEG-rhGH. The ratio of Cmax and the ratio of AUC0-168h from the first to the last dosing were 1.09~1.11 and 1.22~1.26 respectively. A YPEG-rhGH dose-dependent increase in area under effect curve (AUEC) of IGF-1 fold change was observed. Model-derived mean IGF-1 SDS was in the normal range for all three YPEG-rhGH doses. At week 12, HV was 7.07, 10.39, 12.27 cm/year, and 11.58 cm/year for YPEG-rhGH 100, 120, and 140 μg/kg/week and daily rhGH respectively. Adherence and safety were consistent with the profile of daily rhGH. No related serious adverse events were reported.

Conclusion

The PK/PD suggests that YPEG-rhGH is suitable for the once-weekly treatment of pediatric GHD. YPEG-rhGH 120 ~ 140 μg/kg/week provides the closest HV increment with similar safety and tolerability compared to daily rhGH 35 μg/kg/day in children with GHD.

Clinical Trial Registration

ClinicalTrials.gov, identifier [NCT04513171].

Growth of teeth and bones in adult subjects with congenital untreated isolated growth hormone deficiency

OBJECTIVE

To understand the growth of teeth and mandibular and maxillary bones in subjects with isolated growth hormone deficiency (IGHD).

MATERIAL AND METHODS

Mesiodistal tooth width of 28 maxillary and mandibular dental models of 14 adult IGHD subjects (9 men) were digitalized and compared to 40 models of 20 normal-statured controls (11 men). The mean SDS of the maxillary and mandibular teeth were compared with height, cephalic perimeter, total anterior facial height, total maxillary and mandibular length, and maxillary and mandibular arches.

RESULTS

All average mesiodistal dimensions in absolute values of the 14 dental pairs were reduced in the IGHD group. Eight of 28 (28.6%) mesiodistal dimensions in IGHD subjects of both sexes had an average SDS below -2, thirteen of them (46.4%) had mean SDS between -1 and - 2, and seven of them (25.0%) had SDS above -1. The highest SDS values were the upper lateral incisor (-0.32 in women), and the upper canine (-0.91 in men). The lowest SDS values were the 2nd upper molar (-3.51 in men), and the 2nd upper premolar (-2.64 in women). The ascending order of the mean SDS was height, total maxillary length, total mandibular length, total anterior height of the face, cephalic perimeter, the maxillary arches width, the mesiodistal width of the mandibular teeth, the mesiodistal width of the maxillary teeth and the mandibular arches width.

CONCLUSIONS

Reduction in mesiodistal width is present in untreated IGHD adults with magnitude of tooth size reduction being lower than height, cephalic perimeter, total anterior facial height, and most jaw measurements. IGHD abolishes the sexual dimorphism in mesiodistal dental measures.

Safety and Efficacy of Lonapegsomatropin in Children With Growth Hormone Deficiency: enliGHten Trial 2-Year Results

PURPOSE

The objectives of the ongoing, Phase 3, open-label extension trial enliGHten are to assess the long-term safety and efficacy of weekly administered long-acting growth hormone lonapegsomatropin in children with growth hormone deficiency.

METHODS

Eligible subjects completing a prior Phase 3 lonapegsomatropin parent trial (heiGHt or fliGHt) were invited to participate. All subjects were treated with lonapegsomatropin. Subjects in the United States switched to the TransCon hGH Auto-Injector when available. Endpoints were long-term safety, annualized height velocity, pharmacodynamics [insulin-like growth factor-1 SD score (SDS) values], and patient- and caregiver-reported assessments of convenience and tolerability.

RESULTS

Lonapegsomatropin treatment during enliGHten was associated with continued improvements in height SDS through week 104 in treatment-naïve subjects from the heiGHt trial (-2.89 to -1.37 for the lonapegsomatropin group; -3.0 to -1.52 for the daily somatropin group). Height SDS also continued to improve among switch subjects from the fliGHt trial (-1.42 at fliGHt baseline to -0.69 at week 78). After 104 weeks, the average bone age/chronological age ratio for each treatment group was 0.8 (0.1), showing only minimal advancement of bone age relative to chronological age with continued lonapegsomatropin treatment among heiGHt subjects. Fewer local tolerability reactions were reported with the TransCon hGH Auto-Injector compared with syringe/needle.

CONCLUSIONS

Treatment with lonapegsomatropin continued to be safe and well-tolerated, with no new safety signals identified. Children treated with once-weekly lonapegsomatropin showed continued improvement of height SDS through the second year of therapy without excess advancement of bone age.

Skeletal disorders associated with the growth hormone-insulin-like growth factor 1 axis

Growth hormone (GH) and insulin-like growth factor 1 (IGF1) are important regulators of bone remodelling and metabolism and have an essential role in the achievement and maintenance of bone mass throughout life. Evidence from animal models and human diseases shows that both GH deficiency (GHD) and excess are associated with changes in bone remodelling and cause profound alterations in bone microstructure. The consequence is an increased risk of fractures in individuals with GHD or acromegaly, a condition of GH excess. In addition, functional perturbations of the GH-IGF1 axis, encountered in individuals with anorexia nervosa and during ageing, result in skeletal fragility and osteoporosis. The effect of interventions used to treat GHD and acromegaly on the skeleton is variable and dependent on the duration of the disease, the pre-existing skeletal state, coexistent hormone alterations (such as those occurring in hypogonadism) and length of therapy. This variability could also reflect the irreversibility of the skeletal structural defect occurring during alterations of the GH-IGF1 axis. Moreover, the effects of the treatment of GHD and acromegaly on locally produced IGF1 and IGF binding proteins are uncertain and in need of further study. This Review highlights the pathophysiological, clinical and therapeutic aspects of skeletal fragility associated with perturbations in the GH-IGF1 axis.

Effects of adult growth hormone deficiency and replacement therapy on the cardiometabolic risk profile

Adult growth hormone deficiency (AGHD) is considered a rare endocrine disorder involving patients with childhood-onset and adult-onset growth hormone deficiency (AoGHD) and characterized by adverse cardiometabolic risk profile. Besides traditional cardiovascular risk factors, endothelial dysfunction, low-grade inflammation, impaired adipokine profile, oxidative stress and hypovitaminosis D may also contribute to the development of premature atherosclerosis and higher cardiovascular risk in patients with AGHD. Growth hormone replacement has been proved to exert beneficial effects on several cardiovascular risk factors, but it is also apparent that hormone substitution in itself does not eliminate all cardiometabolic abnormalities associated with the disease. Novel biomarkers and diagnostic techniques discussed in this review may help to evaluate individual cardiovascular risk and identify patients with adverse cardiometabolic risk profile. In the absence of disease-specific guidelines detailing how to assess the cardiovascular status of these patients, we generally recommend close follow-up of the cardiovascular status as well as low threshold for a more detailed evaluation.

Adult height after treatment of neurosecretory dysfunction and comparison to idiopathic GHD

OBJECTIVE

Neurosecretory dysfunction (NSD) causes growth hormone deficiency (GHD). Data on adult height after recombinant human growth hormone (rhGH) treatment are lacking.

DESIGN AND PATIENTS

We collected treatment data of all patients with NSD seen between 1990 and 2017 at our outpatient department (tertiary centre) and measured adult height. For comparison, patients with idiopathic GHD were used. Diagnoses were based on short stature (<-2 standard deviation score [SDS]), continuously low height velocity (<25th percentile), delayed bone age (by >1 SD) and low serum IGF-1 concentration (<-2 SDS). NSD was defined by normal GH challenge results, but subnormal spontaneous GH secretion. Exclusion criteria were no information on adult height, underweight and other short stature disorders.

RESULTS

Out of 67 patients diagnosed with NSD, six were still growing, 31 had test results exceeding validated GH cut-offs and three had other disorders causing short stature. Out of the 25 eligible patients with NSD, 21 could be recruited. These patients reached an adult height of -0.85 SDS (mean); 0.34 SDS below midparental height. Height gain during treatment was 2.01 SDS. This outcome was not different to 32 patients with idiopathic GHD.

CONCLUSIONS

Long-term results suggest the viability of the diagnosis of NSD and the efficacy of rhGH treatment.

Treatment Adherence to Injectable Treatments in Pediatric Growth Hormone Deficiency Compared With Injectable Treatments in Other Chronic Pediatric Conditions: A Systematic Literature Review

BACKGROUND

Pediatric patients with growth hormone deficiency (GHD) are currently treated with daily injections of recombinant human growth hormone (rhGH) to promote linear growth and enable attainment of normal adult height. One of the main reasons for suboptimal growth during rhGH therapy is non-adherence to treatment. The objective of this systematic literature review was to examine the recent literature on pediatric adherence to injectable treatments for chronic conditions (focusing on rhGH) to characterize levels of adherence and identify the factors/barriers associated with adherence.

METHODS

The Embase and MEDLINE databases (January 2015-October 2020) were searched to identify publications describing studies of pediatric patients (aged ≤17 years) with GHD and other chronic conditions requiring daily or weekly injectable treatments; a similar targeted search of Chinese literature was also performed. Adherence data were extracted from the included studies and summarized. Risk of bias was determined using the Cochrane Risk of Bias tool 2 or the Newcastle-Ottawa Scale.

RESULTS

A total of 23 publications were included, with all publications except for one (multiple sclerosis) focused on pediatric GHD studies: there were two clinical trials, 18 observational studies and three survey studies. Study sample sizes ranged from 30 to 13,553 patients (median: 95 patients). The definition of adherence varied between studies and included mean adherence rate, median adherence rate, and the percentage of patients within pre-specified adherence categories. Of the publications assessing adherence to daily rhGH, 11 studies reported 12-month mean adherence rate (range: 73.3%- 95.3%) and eight studies reported median adherence (range: 91%- 99.2%). The barriers to treatment adherence identified included self-administration, increased administration frequency, age (adolescence), longer treatment duration, device design, and insufficient family education, awareness, and/or engagement. Recommendations for increasing adherence included using adherence reminder tools, increasing patient engagement/education, and improving injection device design and drug product.

CONCLUSIONS

Adherence to rhGH treatment was high (>80%) for many studies, though comparability between studies was limited given the substantial heterogeneity in the way adherence was defined, measured, and reported. To address this heterogeneity, we recommend standardizing how adherence is defined and reported and encourage the use of standardized study designs and outcome measures.

Curve matching to predict growth in patients receiving growth hormone therapy: An interpretable & explainable method

Curve matching may be used to predict growth outcomes using data of patients whose growth curves resemble those of a new patient with growth hormone deficiency (GHD) and those born small for gestational age (SGA). We aimed to investigate the validity of curve matching to predict growth in patients with GHD and those born SGA receiving recombinant human growth hormone (r-hGH). Height data collected between 0-48 months of treatment were extracted from the easypod™ connect ecosystem and the easypod™ connect observational study. Selected patients with height standard deviation scores (HSDS) [-4, <-1] and age [3, <16y] at start were included. The 'Matching Database' consisted of patients' monthly HSDS obtained by the broken stick method and imputation. Standard deviation (SD) was obtained from the observed minus the predicted HSDS (error) based on matched patients within the 'Matching Database'. Data were available for 3,213 patients in the 'Matching Database', and 2,472 patients with 16,624 HSDS measurements in the observed database. When ≥2 HSDS measurements were available, the error SD for a one-year prediction was approximately 0.2, which corresponds to 1.1 cm, 1.3 cm, and 1.5 cm at 7, 11, and 15 years of age, respectively. Indication and age at treatment start (<11 vs ≥11 years) had a small impact on the error SD, with patients born SGA and patients aged <11 years at treatment start generally having slightly lower values. We conclude that curve matching is a simple and valid technique for predicting growth in patients with GHD and those born SGA.

Expert Opinion on the Management of Growth Hormone Deficiency in Brain Tumor Survivors: Results From an Italian Survey

BACKGROUND

Growth hormone deficiency (GHD) is the first and most common endocrine complication in pediatric brain tumor survivors (BTS). GHD can occur due to the presence of the tumor itself, surgery, or cranial radiotherapy (CRT).

AIMS

This study aimed to evaluate management and adherence to current guidelines of the Italian centers engaged in the diagnosis and follow-up of GHD patients with BTS.

METHODS

A multidisciplinary scientific board of pediatric endocrinologists, oncologists and radiologists with neuroimaging expertise discussed and reviewed the main issues relating to the management of GHD in pediatric BTS and developed a survey. The survey included questions relating to organizational aspects, risk factors, diagnosis, definition of stable disease, and treatment. The online survey was sent to an expanded panel of specialists dedicated to the care of pediatric BTS, distributed among the three specialty areas and throughout the country (23 Italian cities and 37 Centers).

RESULTS

The online questionnaire was completed by 86.5% (32 out of 37) of the Centers involved. Most had experience in treating these patients, reporting that they follow more than 50 BTS patients per year. Responses were analyzed descriptively and aggregated by physician specialty. Overall, the results of the survey showed some important controversies in real life adherence to the current guidelines, with discrepancies between endocrinologists and oncologists in the definition of risk factors, diagnostic work-up, decision-making processes and safety. Furthermore, there was no agreement on the neuroimaging definition of stable oncological disease and how to manage growth hormone therapy in patients with residual tumor and GHD.

CONCLUSIONS

The results of the first Italian national survey on the management of GHD in BTS highlighted the difference in management on some important issues. The time to start and stop rhGH treatment represent areas of major uncertainty. The definition of stable disease remains critical and represents a gap in knowledge that must be addressed within the international guidelines in order to increase height and to improve metabolic and quality of life outcomes in cancer survivors with GHD.

Somatotropic Axis, Pace of Life and Aging

Mice with genetic growth hormone (GH) deficiency or GH resistance live much longer than their normal siblings maintained under identical conditions with unlimited access to food. Extended longevity of these mutants is associated with extension of their healthspan (period of life free of disability and disease) and with delayed and/or slower aging. Importantly, GH and GH-related traits have been linked to the regulation of aging and longevity also in mice that have not been genetically altered and in other mammalian species including humans. Avai+lable evidence indicates that the impact of suppressed GH signaling on aging is mediated by multiple interacting mechanisms and involves trade-offs among growth, reproduction, and longevity. Life history traits of long-lived GH-related mutants include slow postnatal growth, delayed sexual maturation, and reduced fecundity (smaller litter size and increased intervals between the litters). These traits are consistent with a slower pace-of-life, a well-documented characteristic of species of wild animals that are long-lived in their natural environment. Apparently, slower pace-of-life (or at least some of its features) is associated with extended longevity both within and between species. This association is unexpected and may appear counterintuitive, because the relationships between adult body size (a GH-dependent trait) and longevity within and between species are opposite rather than similar. Studies of energy metabolism and nutrient-dependent signaling pathways at different stages of the life course will be needed to elucidate mechanisms of these relationships.

Inside the Noonan "universe": Literature review on growth, GH/IGF axis and rhGH treatment: Facts and concerns

Noonan syndrome (NS) is a disorder characterized by a typical facial gestalt, congenital heart defects, variable cognitive deficits, skeletal defects, and short stature. NS is caused by germline pathogenic variants in genes coding proteins with a role in the RAS/mitogen-activated protein kinase signaling pathway, and it is typically associated with substantial genetic and clinical complexity and variability. Short stature is a cardinal feature in NS, with evidence indicating that growth hormone (GH) deficiency, partial GH insensitivity, and altered response to insulin-like growth factor I (IGF-1) are contributing events for growth failure in these patients. Decreased IGF-I, together with low/normal responses to GH pharmacological provocation tests, indicating a variable presence of GH deficiency/resistance, in particular in subjects with pathogenic PTPN11 variants, are frequently reported. Nonetheless, short- and long-term studies have demonstrated a consistent and significant increase in height velocity (HV) in NS children and adolescents treated with recombinant human GH (rhGH). While the overall experience with rhGH treatment in NS patients with short stature is reassuring, it is difficult to systematically compare published data due to heterogeneous protocols, potential enrolment bias, the small size of cohorts in many studies, different cohort selection criteria and varying durations of therapy. Furthermore, in most studies, the genetic information is lacking. NS is associated with a higher risk of benign and malignant proliferative disorders and hypertrophic cardiomyopathy, and rhGH treatment may further increase risk in these patients, especially as dosages vary widely. Herein we provide an updated review of aspects related to growth, altered function of the GH/IGF axis and cell response to GH/IGF stimulation, rhGH treatment and its possible adverse events. Given the clinical variability and genetic heterogeneity of NS, treatment with rhGH should be personalized and a conservative approach with judicious surveillance is recommended. Depending on the genotype, an individualized follow-up and close monitoring during rhGH treatments, also focusing on screening for neoplasms, should be considered.

PEGylated Recombinant Human Growth Hormone Jintrolong® Exhibits Good Long-Term Safety in Cynomolgus Monkeys and Human Pediatric Growth Hormone Deficiency Patients

Jintrolong^® is a long-acting PEGylated recombinant human growth hormone (PEG-rhGH) developed for weekly injection in patients with pediatric growth hormone deficiency (PGHD). Although PEG modification of therapeutic proteins is generally considered safe, concerns persist about the potential for adverse vacuolation in tissues with long-term exposure to PEG-included therapies, particularly in children. We assessed the safety of Jintrolong^® in cynomolgus monkeys with an examination of vacuolation in the brain choroid plexus (CP) and reported long-term clinical safety data obtained from children with PGHD. The toxicity of Jintrolong^® was assessed following the 52-week administration with doses at 0.3, 1, or 3 mg/kg/week. The levels of vacuolation of CP in animals were dose-dependent and at least partially reversible after a 104- or 157-week recovery period. Vacuolation in the CP epithelium did not lead to obvious subcellular structural or cell functional abnormalities. Compared with the clinical dose of 0.2 mg/kg/week Jintrolong^® in PGHD patients, exposure in monkeys under NOAEL 3 mg/kg/week exhibited safety margins greater than 120.5, the predicted minimum dose to induce vacuolation in monkeys is equivalent to 1.29 mg/kg/week in humans, which is 6.45-fold higher than the clinical dose. The safety data acquired in clinical trials for Jintrolong^® were also analyzed, which included phase III (360 patients), phase IV (3,000 patients) of 26-week treatment, and a follow-up study with treatment lasting for 3 years. There was no statistically significant difference in the incidence of adverse reactions between the Jintrolong^® group and the daily rhGH control group (no PEG), and no new adverse effects (AE) were observed in the Jintrolong^® group at the clinical therapeutic dose of 0.2 mg/kg/week.

Non-GH Agents and Novel Therapeutics in the Management of Short Stature

Short stature is one of the most common reasons for referral to pediatric endocrinologists. The vast majority of short children do not have growth hormone (GH) deficiency or another pathologic process that is interfering with normal growth. While GH has been approved in the US for several etiologies of non-GH deficient short stature, its high cost and need for daily injections represent barriers for many families. Alternative agents for the management of short stature include the use of gonadotropin releasing hormone analogs (GnRHas) to delay puberty, and aromatase inhibitors (AIs) in boys to postpone epiphyseal fusion. The results of studies employing GnRHas as either monotherapy or combined with GH are mixed, and there is a dearth of rigorously designed clinical trials that have followed patients to adult height. While AIs have been found to result in modest increases in adult height in some studies, important questions about their long-term safety exist. The C-type natriuretic peptide analog vosoritide is an experimental agent that is emerging as a potential treatment for a few specific conditions including achondroplasia, although its efficacy in attenuating disproportionality is as yet unproven. While each of these therapeutic strategies holds promise, none are currently considered standard of care and several important questions remain. These include the impact of these interventions on quality of life as well as long-term outcomes.

Bone and body composition analyses by DXA in adults with GH deficiency: effects of long-term replacement therapy

PURPOSE

The effects of growth hormone (GH) replacement on bone mass and body composition in adult with GH deficiency (AGHD) are still debated with regard to their persistence in the long term. Moreover, the impact of the gender on the response to GH is controversial. Aim of this study was to evaluate the long-term effects of rhGH replacement on bone mass and body composition in a monocentric cohort of patients with AGHD.

METHODS

Data from 118 patients with AGHD (34.8 ± 14.4 years, 43 women and 75 men) treated with rhGH for a period of at least 3 years up to a maximum of 10 were retrospectively collected. Bone mineral density (BMD) at the lumbar spine, femur, and 1/3 radius, and total and truncular body composition were evaluated by dual-energy X-ray absorption (DXA) before and during treatment. Clinical and laboratory evaluations were performed before and during the treatment period on an annual basis.

RESULTS

Lumbar spine BMD consistently increased in males, while it decreased in females after a transient improvement observed during the first 4 years of therapy. There were no significant changes in femoral and 1/3 radial BMD in either sexes. Lean mass significantly increased in both sexes, while fat mass only decreased in males.

CONCLUSIONS

In AGHD patients long-term rhGH replacement therapy induces a positive effect with regard to bone mass and body composition. A sexual dimorphism in the response to treatment is evident, with males displaying a more favorable outcome.

Growth hormone deficit. Does the first year of treatment influence adult height?

INTRODUCTION

Short stature is the most frequent reason for Pediatric Endocrinology consultations and sometimes requires treatment with growth hormone.

OBJECTIVE

The possible correlation of a good response to any early response factor with a better final response was studied, and also whether there was a difference in response to treatment according to the type of deficit.

PATIENTS AND METHODS

This was a longitudinal, retrospective and observational study of 139 patients treated for idiopathic growth hormone deficiency up to adult height. There were good response criteria in the first year of treatment: a) an increase in growth rate ≥3 cm/year, b) a growth rate ≥1 standard deviation (SD), c) an increase in height ≥0.5 SD, d) an increase in height ≥0.3 SD. Study of the Index of Responsiveness to treatment in the first and second year. Final response variables: adult height with respect to target height, adult height with respect to initial growth prediction and adult height with respect to initial height at the start of treatment. The possible correlation of a good response to any of the early response factors with a better final response to treatment was studied, and also whether there was a difference in the response to treatment according to the type of deficit.

RESULTS

The treatment produced a gain in adult height with respect to genetic height of 0.06 ± 0.7 SD. Patients considered good responders in the first year of treatment presented a better final response (growth rate ≥3 cm: p = 0.000, growth rate ≥1 SD: p = 0.008, height gain ≥0.5 SD: p = 0.007, height gain ≥0.3 SD: p = 0.006), as well as patients with a severe deficit (p = 0.04). The index of responsiveness to treatment during the first year was associated with a better final response (r = 0.249, p = 0.003), with this correlation being maintained in the second year (r = 0.294, p = 0.01).

CONCLUSIONS

Growth hormone treatment increased height in the genetic target. The percentage of good responders varied depending on the criteria used. The response in the first year of treatment and a severe deficit were determining factors for achieving a good long-term response.

Safety of growth hormone (GH) treatment in GH deficient children and adults treated for cancer and non-malignant intracranial tumors-a review of research and clinical practice

Individuals surviving cancer and brain tumors may experience growth hormone (GH) deficiency as a result of tumor growth, surgical resection and/or radiotherapy involving the hypothalamic-pituitary region. Given the pro-mitogenic and anti-apoptotic properties of GH and insulin-like growth factor-I, the safety of GH replacement in this population has raised hypothetical safety concerns that have been debated for decades. Data from multicenter studies with extended follow-up have generally not found significant associations between GH replacement and cancer recurrence or mortality from cancer among childhood cancer survivors. Potential associations with secondary neoplasms, especially solid tumors, have been reported, although this risk appears to decline with longer follow-up. Data from survivors of pediatric or adult cancers who are treated with GH during adulthood are scarce, and the risk versus benefit profile of GH replacement of this population remains unclear. Studies pertaining to the safety of GH replacement in individuals treated for nonmalignant brain tumors, including craniopharyngioma and non-functioning pituitary adenoma, have generally been reassuring with regards to the risk of tumor recurrence. The present review offers a summary of the most current medical literature regarding GH treatment of patients who have survived cancer and brain tumors, with the emphasis on areas where active research is required and where consensus on clinical practice is lacking.

Safety and effectiveness of replacement with biosimilar growth hormone in adults with growth hormone deficiency: results from an international, post-marketing surveillance study (PATRO Adults)

PURPOSE

To evaluate safety and effectiveness of biosimilar recombinant human growth hormone (rhGH; Omnitrope®) in adults with growth hormone deficiency (GHD), using data from the PATRO Adults study.

METHODS

PATRO Adults was a post-marketing surveillance study conducted in hospitals and specialized endocrinology units across Europe. The primary objective was to assess the safety of rhGH in adults treated in routine clinical practice. All adverse events (AEs) were monitored and recorded for the complete duration of Omnitrope® treatment. Effectiveness was evaluated as a secondary objective.

RESULTS

As of January 2020, 1447 patients (50.9% male) had been enrolled from 82 centers in 9 European countries. Most patients had adult-onset GHD (n = 1179; 81.5%); 721 (49.8%) were rhGH-naïve at study entry. Overall, 1056 patients (73.0%) reported adverse events (AEs; n = 5397 events); the majority were mild-to-moderate in intensity. Treatment-related AEs were reported in 117 patients (8.1%; n = 189 events); the most commonly reported (MedDRA preferred terms) were arthralgia (n = 19), myalgia (n = 16), headache (n = 14), and edema peripheral (n = 10). In total, 495 patients (34.2%) had serious AEs (SAEs; n = 1131 events); these were considered treatment-related in 28 patients (1.9%; n = 35 events). Mean (standard deviation) IGF-I SDS increased from - 2.34 (1.47) at baseline to - 0.23 (1.65) at 12 months, and remained relatively stable thereafter (up to 3 years). Body mass index remained stable between baseline and 3 years.

CONCLUSION

Data from PATRO Adults indicate biosimilar rhGH (Omnitrope^®) is not associated with any unexpected safety signals, and is effective in adults with GHD treated in real-world clinical practice.

Pregnancy outcomes in women receiving growth hormone replacement therapy enrolled in the NordiNet® International Outcome Study (IOS) and the American Norditropin® Studies: Web-Enabled Research (ANSWER) Program

PURPOSE

Data on the safety of growth hormone (GH) replacement therapy during pregnancy are limited. We report a combined analysis of data from pregnant women treated with GH while enrolled in two non-interventional, multicenter studies: NordiNet® International Outcome Study (IOS) and the American Norditropin® Studies: Web-Enabled Research (ANSWER) Program.

METHODS

Pregnancy data were pooled from NordiNet® IOS and the ANSWER Program. Data were collected during routine clinic visits by participating physicians using a web-based system. Patients exposed to GH replacement therapy during pregnancy were included in the analysis.

RESULTS

The study population included 40 female patients with typical causes of adult GH deficiency (GHD). Overall, there were 54 pregnancies. Of these, 47 were exposed to GH between conception and delivery. In 48.9% of pregnancies exposed to GH, the dose was > 0.6 mg/day. GH was continued past conception and then stopped during the first, second, and third trimester, in 27.7%, 17.0%, and 2.1% of pregnancies, respectively. In 29.8%, GH was continued throughout pregnancy, with an unchanged dose in most cases. Of the 47 GH-exposed pregnancies, 37 (78.7%) progressed to normal delivery. There were three adverse events reported in two pregnancies.

CONCLUSION

These real-world data suggest that there were no new safety signals related to GH exposure in women with GHD during pregnancy. These results are consistent with findings from previous studies reporting data in pregnancies exposed to GH at conception or throughout pregnancy. This observational study in additional pregnancies provides further evidence that GH exposure does not adversely affect pregnancy outcome.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT00960128 (date of registration: August 13, 2009) and NCT01009905 (date of registration: November 5, 2009).

Reducing adverse events associated with the glucagon stimulation test for the assessment of growth hormone deficiency in adults with a high prevalence of pituitary hormone deficiencies

DESIGN

A retrospective review of the adverse events (AEs) in 78 patients during the glucagon stimulation test (GST) for the assessment of growth hormone deficiency (GHD) before and after protocol amendments which aimed to reduce AEs in a group of patients with a high prevalence of pituitary hormone deficiencies.

PATIENTS

Based on our observations of frequent AEs during the standard GST protocol in an initial 25 patients (cohort 1), a modified protocol was introduced to include the routine administration of 20 mg of hydrocortisone pre-GST in a subsequent 53 patients (cohort 2). Post hoc analysis of the effect of glucocorticoid dosing pre-GST on AEs was examined in those receiving <20 mg hydrocortisone (group A, n = 19) vs ≥20 mg hydrocortisone (group B, n = 59).

MEASUREMENTS

AEs including hypotension, hypoglycaemia and nausea/vomiting.

RESULTS

Of the 78 patients undergoing the GST, 79% had ≥2 hormone deficiencies. Rates of AEs were 41% vs 30% for hypotension, 60% vs 28% for hypoglycaemia (p < .05) and 20% vs 13% for nausea/vomiting in cohort 1 compared with cohort 2, respectively. Post hoc analysis revealed lower rates of AEs in those receiving ≥20 mg hydrocortisone (group B) compared to those receiving <20 mg due to a reduction in hypoglycaemic events (82% vs 26%, p < .001) and hypotension (50% vs 27%, p = .05). Similar numbers of patients in group A and group B met criteria for GHD.

CONCLUSIONS

In patients with a high prevalence of pituitary deficiencies, a modified GST protocol of additional stress dose glucocorticoid attenuated the frequency of AEs without appearing to compromise the performance of the GST.

Reduced fibroblast growth factor 21 and β-Klotho secretion in untreated congenital isolated GH deficiency

PURPOSES

Increasing evidence suggests that the FGF-Klotho endocrine system and the somatotropic system (pituitary and extra-pituitary GH) may have important metabolic and immune relationships, thus contributing to the pathophysiology of aging-related disorders, including diabetes, atherosclerosis, and cancer. The status of these interactions in isolated GH deficiency (IGHD) is unknown. The objective of this study was to assess the response of both FGF21 and β-Klotho levels to a standard meal in a homogeneous group of adults with congenital untreated IGHD due to a homozygous mutation in the GHRH receptor gene.

METHODS

In a cross-sectional study, we measured the levels of FGF21 and β-Klotho, before and 30, 60, 120, and 180 min after a standardized test meal in 20 (11 males) IGHD and 20 (11 males) age-matched controls. Areas under the curves (AUC) of FGF21 and β-Klotho were calculated.

RESULTS

Baseline levels of FGF21 were similar, but baseline levels of β-Klotho were lower in IGHD subjects. The IGHD individuals exhibited lower AUC for FGF21 and β-Klotho levels than control subjects. There was a positive correlation between IGF1 and β-Klotho levels in the pooled groups. No correlation was found between IGF1 and FGF21 levels.

CONCLUSIONS

Subjects with lifetime, untreated IGHD exhibit reduced FGF21 and β-Klotho levels response to a mixed meal. This difference may have consequences on metabolism and aging.

Congenital growth hormone deficiency associated with hip dysplasia and Legg-Calve-Perthes disease

OBJECTIVE

Growth hormone deficiency (GHD) is usually treated with recombinant human GH (rhGH), and this has been rarely associated with hip disorders. We analysed the clinical data of patients with congenital GHD receiving rhGH who had associated hip dysplasia or Legg-Calve-Perthes disease (LCPD), with a view to determining whether the hip dysplasia was associated with the underlying disease or with rhGH treatment.

DESIGN

We performed a retrospective analysis of paediatric and adolescent patients seen between 1992-2018 with congenital GHD and hip disorders. Data were collected through a review of the patients' medical records and included demographics, clinical and imaging data, and the time frame between the onset of the symptoms related to the hip disorders and the onset of GH treatment.

RESULTS

Of the 13 patients with hip disorders, hip dysplasia was present in ten patients and LCPD in three. Hip dysplasia was diagnosed before rhGH was initiated in 50% of cases. These patients had bilateral hip dysplasia and isolated GHD. LCPD was diagnosed in one patient before rhGH was commenced and did not progress. In two patients, LCPD was diagnosed after rhGH was started and did temporarily progress in one of them, but rhGH was not discontinued because LCPD did not seem to be related to rhGH treatment.

CONCLUSIONS

This study suggests that hip dysplasia could be a manifestation of an underlying GHD. Additionally, rhGH treatment may not necessarily be causative of LCPD.