Impact of BMI on peak growth hormone responses to provocative tests and therapeutic outcome in children with growth hormone deficiency

Clinical and laboratory characteristics but not response to treatment can distinguish children with definite growth hormone deficiency from short stature unresponsive to stimulation tests

Introduction

It has been proposed that not all children with short stature displaying an inadequate response to tests for growth hormone (GH) secretion truly suffer from GH deficiency (GHD). Only children with a monogenic cause of GHD or an identifiable combined hormonal deficiency or anatomical anomaly in the hypothalamic-pituitary axis should be considered definite GHD (dGHD). The remaining patients can be defined as a separate group of patients, "short stature unresponsive to stimulation tests" (SUS). The aim of this proof-of-concept study, was to assess whether SUS patients treated with rhGH exhibit any differences compared to GHD patients undergoing the same treatment.

Methods

Retrospective analysis on 153 consecutive patients with short stature and pathological response to two GH stimulation tests. Patients with dGHD were defined as those with a clear genetic or anatomical hypothalamic-pituitary anomaly, as well as those with combined pituitary hormone deficiencies and those with a known insult to the hypothalamic-pituitary axis (i.e. total brain irradiation) (n=38, 25%); those without any of the previous anomalies were defined as SUS (n=115, 75%).

Results

At diagnosis, dGHD and SUS populations did not differ significantly in sex (F 32% vs 28%, p=0.68), age (11.9 vs 12.1, p=0.45), height SDS at diagnosis (-2.2 vs. -2.0, p=0.35) and prevalence of short stature (height <-2 SDS) (56% vs 51%, p=0.45). IGF-1 SDS were significantly lower in dGHD (-2.0 vs -1.3, p<0.01). After 1 year of treatment, the prevalence of short stature was significantly reduced in both groups (31% in dGHD vs. 21% in SUS, p<0.01) without any significant differences between groups (p=0.19), while the increase in IGF-1 SDS for bone age was greater in the dGHD category (+1.9 vs. +1.5, p<0.01), with no further difference in IGF-1 SDS between groups. At the last available follow-up, 59 patients had reached the near adult height (NAH) and underwent retesting for GHD. No differences in NAH were found (-0.3 vs. -0.4 SDS, 0% vs. 4% of short stature). The prevalence of pathological retesting was higher in dGHD (60% vs. 10%, p<0.01) as well as of overweight and obesity (67% vs. 26%).

Conclusion

Stimulation tests and the equivalent benefit from rhGH therapy, cannot distinguish between dGHD and SUS populations. In addition, lower IGF-1 concentrations at baseline and their higher increase during treatment in dGHD patients, and the lack of pathological retesting upon reaching NAH in SUS patients, are facts that suggest that deficient GH secretion may not be the cause of short stature in the SUS studied population.

Clinical Features of Transient Growth Hormone Deficiency

Background: Most patients with idiopathic growth hormone deficiency (iGHD) in childhood have normal GH stimulation test results in adulthood. The present study aimed to investigate the characteristics and possible etiology of transient iGHD. Methods: Patients with childhood-onset iGHD who completed their GH treatment between March 2010 and March 2021 were retrospectively studied. Patients with a clear history of child abuse or constitutional delay of growth and puberty were excluded. Ten patients with a diagnosis of iGHD based on a decreased growth rate and growth hormone stimulation test findings at the time of onset were included. Retesting demonstrated that these patients had a normal GH level. Results: Five patients had insufficient weight gain (BMI SD score < −1.0 at the start of treatment or a decrease in BMI SD score > 1.0 from one year before treatment to the start of treatment). The other five patients had no remarkable clinical features. One patient had decreased height velocity at the same time as their sibling. Conclusion: Insufficient pre-treatment weight gain or a familial cluster of cases may be related to low GH peaks of GHST, leading to a diagnosis of transient GHD.

Effects of lifestyle intervention on IGF-1, IGFBP-3, and insulin resistance in children with obesity with or without metabolic-associated fatty liver disease

Obesity is a strong predictor for metabolic associated fatty liver disease (MAFLD), which has been associated with decreased insulin like growth factor 1 (IGF-1). In obesity, weight loss increases growth hormone secretion, but this is not unequivocally associated with increases in serum IGF-1 and IGF binding protein-3 (IGFBP-3). We studied the changes in the IGF axis in relation to weight loss and improvement in insulin resistance in children with or without MALFD after 10 weeks of lifestyle intervention at a weight loss camp (WLC). We investigated 113 (66 females) Caucasian children with obesity, median age 12.4 (range 7.3-14.6) years, before and after 10 weeks of lifestyle intervention at a WLC. We investigated children who was either MAFLD positive (n = 54) or negative (n = 59) before and after WLC. Children with MAFLD had lower baseline IGF-1 (249 ± 112 vs 278 ± 107 µg/l, P = 0.048), whereas the IGF-1/IGFBP-3 molar ratio was similar to children without MAFLD (19.4 ± 6.6 vs. 21.8 ± 6.6%, P = 0.108). When all children were considered as one group, WLC decreased SDS-BMI and HOMA-IR (P < 0.001, both) and increased IGF-1 (264 ± 110 vs 285 ± 108 µg/l, P < 0.001) and the IGF/IGFBP-3 molar ratio (20.7 ± 6.7 vs 22.4 ± 6.1%, P < 0.001). When categorized according to liver status, IGF-1 increased significantly in children with MAFLD (P = 0.008) and tended to increase in children without MAFLD (P = 0.052).   Conclusions: Ten weeks of lifestyle intervention decreased insulin resistance and improved the IGF axis. We observed slight differences in the IGF axis in relation to MAFLD status. This suggests that the IGF axis is primarily influenced by insulin resistance rather than MAFLD status. What is New: • Weight loss decreases insulin resistance and subsequently increases the IGF axis in children with obesity. • Children with MAFLD had an aberration in the IGF axis compared to their MAFLD negative counter parts and the IGF axis was primarily influenced by the decreased BMI-SDS and insulin resistance, rather than MAFLD status. What is Known: • NAFLD has previously been associated with reduced serum IGF-1 concentrations. • Data on the impact of MAFLD and aberrations in the growth hormone and IGF axis and the effects of lifestyle interventions in children are limited.

Growth hormone responses during arginine and clonidine stimulation test: Correlations with patients' auxological and metabolic parameters in a single centre study

BACKGROUND

Children with auxological parameters defining a 'short stature' is routinely subjected to various blood tests and, if necessary, to growth hormone stimulation test (GHST) for differentiating GH deficiency (GHD) and other causes of stunted growth.

AIM

This retrospective monocentric study aimed to evaluate any correlations between GH peaks during GHST in children assessed for short stature and their auxological/metabolic parameters, highlighting differences between GHD and idiopathic short stature.

PATIENTS AND METHODS

We reviewed the medical records of 74 children with short stature (height lower than the third percentile according to standardized growth curves for the Italian population) managed at the Pediatric Day Hospital of our Department of Life Sciences and Public Health in Università Cattolica Sacro Cuore, Rome, who performed at least two GHSTs, using arginine and clonidine as stimulants, for assessment of GH secretion. The results of a total number of 161 GHSTs, performed in 42 children diagnosed with GHD and in 32 children with other causes of short stature, were analyzed.

RESULTS

We found significantly lower serum levels of insulin growth factor-1 (IGF-1) and increased levels of thyroid-stimulating hormone (TSH) in children with GHD, without other metabolic differences in comparison to children with other causes of short stature. There was also a correlation between triglycerides and GH peak during arginine test, while fT4 and LDL concentrations correlated with GH peak during the third test, if performed. Pre-test BMI (rho -0.274, p = 0.01) and weight (rho -0.251, p = 0.03) have influenced GH peak during clonidine stimulation test. Metabolic and auxological parameters could influence GH peak during clonidine and arginine stimulation tests and must be taken into account when interpreting GHST results.

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.

Effects of Metformin on Bone Mineral Density and Adiposity-Associated Pathways in Animal Models with Type 2 Diabetes Mellitus: A Systematic Review

Recently, there have been investigations on metformin (Met) as a potential treatment for bone diseases such as osteoporosis, as researchers have outlined that type 2 diabetes mellitus (T2DM) poses an increased risk of fractures. Hence, this systematic review was conducted according to the 2020 PRISMA guidelines to evaluate the evidence that supports the bone-protective effects of metformin on male animal models with T2DM. Five databases—Google Scholar, PubMed, Wiley Online Library, SCOPUS, and ScienceDirect—were used to search for original randomized controlled trials published in English with relevant keywords. The search identified 18 articles that matched the inclusion criteria and illustrated the effects of Met on bone. This study demonstrates that Met improved bone density and reduced the effects of T2DM on adiposity formation in the animal models. Further research is needed to pinpoint the optimal dosage of Met required to exhibit these therapeutic effects.

Visceral adiposity is associated with metabolic profiles predictive of type 2 diabetes and myocardial infarction

Background

Visceral fat (VF) increases risk for cardiometabolic disease (CMD), the leading cause of morbidity and mortality. Variations in the circulating metabolome predict the risk for CMD but whether or not this is related to VF is unknown. Further, CMD is now also present in adolescents, and the relationships between VF, circulating metabolome, and CMD may vary between adolescents and adults.

Methods

With an aim to add understanding to the metabolic variations in visceral obesity, we tested associations between VF, measured directly with magnetic resonance imaging, and 228 fasting serum metabolomic measures, quantified with nuclear magnetic resonance spectroscopy, in 507 adults (36–65 years) and 938 adolescents (12–18 years). We further utilized data from published studies to estimate similarities between VF and CMD-associated metabolic profiles.

Results

Here we show that VF, independently of body mass index (BMI) or subcutaneous fat, is associated with triglyceride-rich lipoproteins, fatty acids, and inflammation in both adults and adolescents, whereas the associations with amino acids, glucose, and intermediary metabolites are significant in adults only. BMI-adjusted metabolomic profile of VF resembles those predicting type 2 diabetes in adults (R² = 0.88) and adolescents (R² = 0.70), and myocardial infarction in adults (R² = 0.59) and adolescents (R² = 0.40); this is not the case for ischemic stroke (adults: R² = 0.05, adolescents: R² = 0.08).

Conclusions

Visceral adiposity is associated with metabolomic profiles predictive of type 2 diabetes and myocardial infarction even in normal-weight individuals and already in adolescence. Targeting factors contributing to the emergence and maintenance of these profiles might ameliorate their cumulative effects on cardiometabolic health.

Obesity increases risk for multiple diseases, likely due to changes in how the body breaks down carbohydrates and fats and due to the molecules that circulate in the blood as a result. In obesity, the accumulation of fat around the internal organs of the abdomen (visceral fat) may be more detrimental than fat accumulation elsewhere in the body. Here, we show that visceral fat is associated with variations in the levels of various molecules in the blood, and these variations are similar to those that can predict type 2 diabetes and heart disease, not only in adults but also in adolescents. This suggests that visceral fat accumulation may be closely related to development of these diseases from a young age.

Raheem, Sliz et al. study the serum metabolome and an imaging-based measure of visceral fat in adults and adolescents. The authors find that, independently of BMI, visceral fat quantity is associated with a metabolomic profile similar to those predictive of type 2 diabetes and myocardial infarction.

Association between overweight and growth hormone secretion in patients with non-functioning pituitary tumors

Introduction

Growth hormone (GH) deficiency (GHD) is often complicated by non-functioning pituitary tumors (NFPTs); however, its prevalence remains unclear because preoperative screening for GHD with provocative tests is not recommended. Accordingly, we attempted to clarify the characteristics of GHD in unoperated patients with NFPT.

Materials and methods

We retrospectively reviewed adult patients with non-functioning pituitary adenoma (NFPA) and Rathke’s cyst who underwent preoperative GH-releasing peptide-2 (GHRP-2) tests from January 2013 to December 2016. We investigated the association between peak GH response to GHRP-2 and background characteristics.

Results

Among 104 patients (85 NFPA and 19 Rathke’s cysts), 45 (43%) presented severe GHD, as diagnosed using GHRP-2 tests. Body mass index (β = -0.210, P = 0.007), free thyroxine (β = 0.440, P < 0.001), and tumor height (β = -0.254, P < 0.001) were significant variables for determining the peak GH response to GHRP-2 in multiple regression analyses. Overweight (odds ratio, 3.86; 95% confidence interval, 1.02–14.66) was significantly associated with severe GHD after adjustment for age, sex, creatinine, free thyroxine, tumor height and clinical diagnosis. The regression slopes between tumor height and peak GH response to GHRP-2 significantly differed between overweight patients and non-overweight individuals, as determined by analysis of covariance (P = 0.040). In the 48 patients who underwent postoperative GHRP-2 tests, severe postoperative GHD was significantly more common in overweight patients than non-overweight individuals (100% vs. 48%, P < 0.001).

Conclusion

We observed a negative synergistic effect between overweight and tumor size on GH secretion in patients with NFPTs, indicating that GH provocation tests for diagnosing underestimated GHD could be considered in overweight unoperated patients with large NFPTs.

Inclusion and Withdrawal Criteria for Growth Hormone (GH) Therapy in Children with Idiopathic GH Deficiency—Towards Following the Evidence but Still with Unresolved Problems

According to current guidelines, growth hormone (GH) therapy is strongly recommended in children and adolescents with GH deficiency (GHD) in order to accelerate growth rate and attain normal adult height. The diagnosis of GHD requires demonstration of decreased GH secretion in stimulation tests, below the established threshold value. Currently, GHD in children is classified as secondary insulin-like growth factor-1 (IGF-1) deficiency. Most children diagnosed with isolated GHD present with normal GH secretion at the attainment of near-final height or even in mid-puberty. The most important clinical problems, related to the diagnosis of isolated GHD in children and to optimal duration of rhGH therapy include: arbitrary definition of subnormal GH peak in stimulation tests, disregarding factors influencing GH secretion, insufficient diagnostic accuracy and poor reproducibility of GH stimulation tests, discrepancies between spontaneous and stimulated GH secretion, clinical entity of neurosecretory dysfunction, discrepancies between IGF-1 concentrations and results of GH stimulation tests, significance of IGF-1 deficiency for the diagnosis of GHD, and a need for validation IGF-1 reference ranges. Many of these issues have remained unresolved for 25 years or even longer. It seems that finding solutions to them should optimize diagnostics and therapy of children with short stature.

Differential Diagnosis of the Short IGF-I-Deficient Child with Apparently Normal Growth Hormone Secretion

The current differential diagnosis for a short child with low insulin-like growth factor I (IGF-I) and a normal growth hormone (GH) peak in a GH stimulation test (GHST), after exclusion of acquired causes, includes the following disorders: (1) a decreased spontaneous GH secretion in contrast to a normal stimulated GH peak ("GH neurosecretory dysfunction," GHND) and (2) genetic conditions with a normal GH sensitivity (e.g., pathogenic variants of GH1 or GHSR) and (3) GH insensitivity (GHI). We present a critical appraisal of the concept of GHND and the role of 12- or 24-h GH profiles in the selection of children for GH treatment. The mean 24-h GH concentration in healthy children overlaps with that in those with GH deficiency, indicating that the previously proposed cutoff limit (3.0-3.2 μg/L) is too high. The main advantage of performing a GH profile is that it prevents about 20% of false-positive test results of the GHST, while it also detects a low spontaneous GH secretion in children who would be considered GH sufficient based on a stimulation test. However, due to a considerable burden for patients and the health budget, GH profiles are only used in few centres. Regarding genetic causes, there is good evidence of the existence of Kowarski syndrome (due to GH1 variants) but less on the role of GHSR variants. Several genetic causes of (partial) GHI are known (GHR, STAT5B, STAT3, IGF1, IGFALS defects, and Noonan and 3M syndromes), some responding positively to GH therapy. In the final section, we speculate on hypothetical causes.

The correlation of serum/plasma IGF-1 concentrations with obstructive sleep apnea hypopnea syndrome: A meta-analysis and meta-regression

BACKGROUND

Obstructive sleep apnea hypopnea syndrome (OSAHS) is a common disease that has serious cardiovascular and metabolic effects. Insulin-like growth factor 1 (IGF-1) levels are reportedly reduced in patients with OSAHS; however, this is still a matter of debate. Therefore, we investigated the association between serum/plasma IGF-1 levels and OSAHS in this meta-analysis.

METHODS

Wan Fang, Excerpta Medica dataBASE, Web of Science, China National Knowledge Infrastructure, VIP, PubMed, and other databases were searched for materials published in any language before April 2, 2022. Two researchers analyzed the studies for quality according to the Newcastle-Ottawa Scale. The acquired data were analyzed using Stata 11.0 and R 3.6.1 software. The effect size was estimated and calculated using standard mean differences and correlation coefficients. Moreover, a combined analysis was conducted using either a random- or fixed-effects model.

RESULTS

Ultimately, 34 studies met our inclusion criteria. Our findings revealed that the plasma/serum IGF-1 concentrations in patients with OSAHS was significantly reduced compared with those in healthy subjects. Subgroup analyses were performed according to OSAHS severity, ethnicity, age, body mass index, specimen testing method, and study design. The outcomes suggested that nearly all subgroups of patients with OSAHS had reduced serum IGF-1 levels. Disease severity and differences in ethnicity were identified as possible influencing factors of serum IGF-1 levels in patients with OSAHS in the meta-regression analysis, and no other factors were found to alter plasma/serum IGF-1 concentrations. Moreover, plasma/serum IGF-1 concentrations were negatively correlated with apnea-hypopnea index and oxygen desaturation index scores and positively associated with minimum oxygen saturation.

CONCLUSION

Serum/plasma IGF-1 concentrations in patients with OSAHS were greatly reduced compared with those of patients in the control group, and were negatively correlated with apnea-hypopnea index and oxygen desaturation index scores and positively correlated with minimum oxygen saturation.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022322738.

Evaluation of growth hormone deficiency in children with cystic fibrosis

Background:

Due to chronic respiratory and gastrointestinal problems, growth failure is a common issue in patients with cystic fibrosis (CF). The present study aimed to investigate the prevalence of growth hormone deficiency (GHD) in CF children with stable gastrointestinal and respiratory conditions.

Materials and Methods:

In this study, the growth indicators of all 4–16-year-old children referred to two CF clinics were monitored over 3 years. Children without severe gastrointestinal or pulmonary symptoms with weight <3% percentile or whose height increase were two standard deviations below their expected height growth over 6 months were selected for the growth hormone (GH) stimulation test by clonidine and L-dopa test. Some of the children without CF, who were also referred for height growth disorders and matched the CF group, were considered the control group. They underwent the GH stimulation test, and the results were compared.

Results:

From 150 patients with CF, growth failure was observed in 24 patients with stable gastrointestinal and respiratory conditions; in 10 of them, the GH stimulation test was deficient. The prevalence of GHD was 6.6% in CF patients. In the control group of 30 children without CF, but with growth failure, the GH was deficient in nine cases, implying no significant difference with the case group (P = 0.37).

Conclusion:

In our study, the prevalence of GHD was 6.6% in CF patients, whereas the prevalence GHD in the normal population of childhood is <1%. Therefore, further studies should be designed to investigate the cause of GHD in CF patients.

Effect of body mass index on peak growth hormone level after growth hormone stimulation test in children with short stature

PURPOSE

The aim of this study is to evaluate the effect of body mass index (BMI) on peak serum growth hormone (GH) level after GH stimulation test in children with short stature.

METHODS

Data were obtained from retrospective medical record reviews of those who visited the pediatric endocrine clinic at St. Vincent's Hospital of Catholic University for short stature from January 2010 to June 2019. A total of 115 children (66 boys and 49 girls) whose height was less than the third percentile according to age and sex underwent GH stimulation testing.

RESULTS

Of the 115 subjects, 47 were diagnosed with GH deficiency (GHD) and 68 were diagnosed with idiopathic short stature (ISS). In patients with GHD, weight standard deviation score (SDS) (P&lt;0.001) and BMI SDS (P≤0.001) were higher, and free thyroxine (T4) level (P=0.012) was lower than those in the ISS group. In total subjects, peak serum GH level after GH stimulation test showed negative correlations with weight SDS (r=-0.465, P&lt;0.001), BMI SDS (r=-0.398, P&lt;0.001), and thyroid stimulating hormone (r=-0.248, P=0.008) and a positive correlation with free T4 (r=0.326, P&lt;0.001). In multiple regression analysis, BMI SDS (P=0.003) was negatively associated with peak serum GH level in GH stimulation testing after adjusting for age, sex, pubertal status, and type of pharmacological stimulus.

CONCLUSION

The BMI SDS influences peak serum GH level after GH stimulation testing. We should consider BMI factors when interpreting the results of GH stimulation testing.

Impact of body mass index on growth hormone stimulation tests in children and adolescents: a systematic review and meta-analysis

Peak stimulated growth hormone (GH) levels are known to decrease with increasing body mass index (BMI), possibly leading to overdiagnosis of GH deficiency (GHD) in children with overweight and obesity. However, current guidelines do not guide how to interpret the peak GH values of these children. This systematic review and meta-analysis aimed to study the effect of the BMI standard deviation score (SDS) on stimulated peak GH values in children, to identify potential moderators of this association, and to quantify the extent to which peak GH values in children with obesity are decreased. This systematic review was performed by the PRISMA guidelines. Medline, Embase, Cochrane, Web of Science, and Google Scholar databases were searched for studies reporting the impact of weight status on peak GH in children. Where possible, individual participant data was extracted and/or obtained from authors. Quality and risk of bias were evaluated using the Scottish Intercollegiate Guidelines Network (SIGN) checklists. The primary outcome was the association between peak GH values and BMI SDS. The pooled correlation coefficient r, 95% confidence interval (CI), and heterogeneity statistic I² were calculated under a multilevel, random-effects model. In addition, exploratory moderator analyses and meta-regressions were performed to investigate the effects of sex, pubertal status, presence of syndromic obesity, mean age and mean BMI SDS on the study level. For the individual participant dataset, linear mixed-models regression analysis was performed with BMI SDS as the predictor and ln(peak GH) as the outcome, accounting for the different studies and GH stimulation agents used. In total, 58 studies were included, providing data on n = 5135 children (576 with individual participant data). Thirty-six (62%) studies had high, 19 (33%) medium, and 3 (5%) low risks of bias. Across all studies, a pooled r of -0.32 (95% CI -0.41 to -0.23, n = 2434 patients from k = 29 subcohorts, I² = 75.2%) was found. In meta-regressions, larger proportions of males included were associated with weaker negative correlations (p = 0.04). Pubertal status, presence of syndromic obesity, mean age, and mean BMI SDS did not moderate the pooled r (all p > 0.05). Individual participant data analysis revealed a beta of -0.123 (95% CI -0.160 to -0.086, p < 0.0001), i.e. per one-point increase in BMI SDS, peak GH decreases by 11.6% (95% CI 8.3-14.8%). To our knowledge, this is the first systematic review and meta-analysis to investigate the impact of BMI SDS on peak GH values in children. It showed a significant negative relationship. Importantly, this relationship was already present in the normal range of BMI SDS and could lead to overdiagnosis of GHD in children with overweight and obesity. With the ever-rising prevalence of pediatric obesity, there is a need for BMI (SDS)-specific cutoff values for GH stimulation tests in children. Based on the evidence from this meta-analysis, we suggest the following weight status-adjusted cutoffs for GH stimulation tests that have cutoffs for children with normal weight of 5, 7, 10, and 20 µg/L: for overweight children: 4.6, 6.5, 9.3, and 18.6 µg/L; and for children with obesity: 4.3, 6.0, 8.6, and 17.3 µg/L.

Provocative growth hormone testing in children: how did we get here and where do we go now?

OBJECTIVES

Provocative growth hormone (GH) tests are widely used for diagnosing pediatric GH deficiency (GHD). A thorough understanding of the evidence behind commonly used interpretations and the limitations of these tests is important for improving clinical practice.

CONTENT

To place current practice into a historical context, the supporting evidence behind the use of provocative GH tests is presented. By reviewing GH measurement techniques and examining the early data supporting the most common tests and later studies that compared provocative agents to establish reference ranges, the low sensitivity and specificity of these tests become readily apparent. Studies that assess the effects of patient factors, such as obesity and sex steroids, on GH testing further bring the appropriateness of commonly used cutoffs for diagnosing GHD into question.

SUMMARY AND OUTLOOK

Despite the widely recognized poor performance of provocative GH tests in distinguishing GH sufficiency from deficiency, limited progress has been made in improving them. New diagnostic modalities are needed, but until they become available, clinicians can improve the clinical application of provocative GH tests by taking into account the multiple factors that influence their results.

Microdeletion in the IGF-1 receptor gene of a patient with short stature and obesity: a case report

OBJECTIVES

Defects in the IGF-1 receptor gene (IGF1R) induce IGF-1 resistance, characterized by intrauterine and postnatal growth retardation, normal or elevated serum IGF-1 levels, and feeding problems. Obesity, idiopathic growth hormone deficiency (IGHD), bone age advancement, and serum IGF-1 level in the lower half of the reference range are very rare clinical features in patients with IGF1R defects.

CASE PRESENTATION

In this study, we report the atypical clinical manifestations of IGF1R defects. Short stature girl born small for gestational age were initially diagnosed with IGHD. No catch-up growth was achieved despite sufficiently elevated IGF-1 levels after recombinant human growth hormone (rhGH) treatment. Single nucleotide polymorphism microarray analysis finally confirmed terminal deletion of 15q26.2q26.3 in the subject.

CONCLUSION

Intrauterine growth retardation, postnatal growth failure, and IGF-1 resistance during rhGH treatment are homologous features exhibited by affected patients, and may be predictive of IGF1R defects.

Association between triglyceride glucose index and peak growth hormone in children with short stature

Growth hormone (GH) secretion is related to many factors, such as weight and puberty, and the reproducibility of GH provocation tests is very poor. This study aimed to evaluate whether the triglyceride (TyG) index was associated with peak GH in children with short stature. This study included 1095 children with short stature divided into two groups based on peak GH level in GH provocation tests [GH deficiency (GHD) group = 733 children; non-GHD group = 362 children]. We found that the TyG index was significantly higher in the GHD group than in the non-GHD group (P < 0.001). A nonlinear relationship was detected between the TyG index and peak GH, whose point was 7.8. A significant negative association between the TyG index and peak GH was observed when the TyG index was greater than 7.8 (β − 2.61, 95% CI − 3.98, − 1.24; P < 0.001), whereas, the relationship between the TyG index and peak GH was not significant when the TyG index was lower than 7.8 (β 0.25, 95% CI − 1.68, 2.17; P = 0.799). There is a nonlinear relationship between the TyG index and peak GH, and a higher TyG index is associated with decreased peak GH in children with short stature.

Dexamethasone Stimulation Test in the Diagnostic Work-Up of Growth Hormone Deficiency in Childhood: Clinical Value and Comparison With Insulin-Induced Hypoglycemia

CONTEXT

dexamethasone has been demonstrated to elicit GH secretion in adults, but few data are available about its effectiveness as a provocative stimulus in the diagnostic work-up of GH deficiency (GHD) in childhood.

OBJECTIVE

to assess the clinical value of dexamethasone stimulation test (DST) as a diagnostic tool for pediatric GHD.

DESIGN AND SETTING

retrospective single-center analysis. The study population included 166 patients with a pathological response to arginine stimulation test (AST, first-line test) and subsequently tested with either insulin tolerance test (ITT) or DST as a second-line investigation between 2008 and 2019.

MAIN OUTCOME MEASURES

comparison between GH peaks and secretory curves induced by ITT and DST; degree of agreement between DST and AST versus ITT and AST.

RESULTS

the pathological response to AST (GH peak < 8 ng/mL) was confirmed by an ITT in 80.2% (89/111) of patients and by a DST in 76.4% (42/55), with no statistical difference between the two groups (p value 0.69). Mean GH peaks achieved after ITT and DST were entirely comparable (6.59 ± 3.59 versus 6.50 ± 4.09 ng/ml, respectively, p 0.97) and statistically higher than those elicited by arginine (p < 0.01 for both), irrespectively of the average GH peaks recorded for each patient (Bland-Altman method). Dexamethasone elicited a longer lasting and later secretory response than AST and ITT. No side effects were recorded after DST.

CONCLUSIONS

DST and ITT confirmed GHD in a superimposable percentage of patients with a pathological first-line test. DST and ITT share a similar secretagogue potency, overall greater than AST.