Influence of body mass index on growth hormone responses to classic provocative tests in children with short stature

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.

The landscape of retesting in childhood-onset idiopathic growth hormone deficiency and its reversibility: a systematic review and meta-analysis

OBJECTIVE

Children diagnosed with idiopathic isolated growth hormone deficiency (IGHD) are frequently observed to no longer be GH-deficient at a later stage of growth as a result of 'GHD reversal'. Reevaluation of GH status by stimulation test is currently incorporated into management guidelines at attainment of final height (FH). Over the past three decades, numerous studies have evaluated reversal rates using different methodologies including crucial parameters like GHD aetiology, GH cut-off and retesting time point, with heterogeneous results. We aimed to systematically analyse the reversibility of childhood-onset IGHD dependent on retesting GH cut-offs and retesting time points.

METHODS

PubMed, Cochrane Library, TRIP database and NHS Evidence were searched for publications investigating the reversibility of IGHD from database initiation to 30 June 2020 following PRISMA recommendations. Study cohorts were pooled according to retesting GH cut-off and time point. Reversal rates were calculated using random-effects models.

RESULTS

Of the 29 studies initially identified, 25 provided sufficient detail for IGHD analysis, resulting in 2030 IGHD patient data. Reversal rates decreased significantly as the retesting GH cut-off increased (P = 0.0013). Pooled (95% CI) reversal rates were 80% (59-92%, n = 227), 73% (62-81%, n = 516) and 55% (41-68%, n = 1287) for cohorts using retesting GH cut-offs of 3-4 ng/mL, 5-6 ng/mL and 7.7-10 ng/mL, respectively. Individuals retested at FH (n = 674) showed a pooled reversal rate of 74% (64-82%) compared to 48% (25-71%) when retested before FH (n = 653).

CONCLUSION

Provided evidence supports reevaluation of current IGHD management guidelines. The high reversal rates should instigate consideration of early retesting.

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

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

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<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<0.001), BMI SDS (r=-0.398, P<0.001), and thyroid stimulating hormone (r=-0.248, P=0.008) and a positive correlation with free T4 (r=0.326, P<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.

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

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

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

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

Association between Insulin-Like Growth Factor-1 and Relative Skeletal Maturation: A Retrospective Cohort Study of Short Children and Adolescents

Objective

Delays in skeletal maturity are related to bone mass and fracture risk in children, but the factors that determine it are unknown. We aimed to identify the association between insulin-like growth factor-1 (IGF-1) and skeletal maturation before and after growth hormone (GH) treatment.

Methods

In this retrospective cohort study, we observed 783 short children and adolescents, 229 of whom received GH therapy. Skeletal maturation was assessed based on the difference between bone age (BA) and chronological age (CA) (noted as BA-CA). Anthropometric data and laboratory values were measured, and BA was evaluated using the Greulich and Pyle method.

Results

The delayed BA group was defined as BA‐CA < −2 SD (n = 457), and the occurrence rate of BA delay was 58.37%. A nonlinear relationship was observed between the IGF-1 standard deviation score (IGF-1 SDS) and BA-CA before and after GH therapy. Before GH therapy, there was a significant positive association between the IGF-1 SDS and BA-CA when the IGF-1 level was greater than -2 SDS (β 0.17, 95% CI 0.08, 027; P < 0.001). However, we did not observe a significant relationship between the IGF-1 SDS and BA-CA when the IGF-1 level was lower than -2 SDS (β 0.07, 95% CI -0.12, 0.26; P = 0.454). After GH therapy, there was a significant positive association between the IGF-1 SDS and BA-CA when the IGF-1 level was lower than 2 SDS (β 0.20, 95% CI 0.12, 028; P < 0.001). However, we did not observe a significant relationship between the IGF-1 SDS and BA-CA when the IGF-1 level was greater than 2 SDS (β -0.03, 95% CI -0.33, 0.27; P = 0.866).

Conclusion

BA is more delayed in short children and adolescents. There is a nonlinear relationship between IGF-1 and BA maturation in short children before and after GH treatment. These findings suggest that a low level of IGF-1 may contribute to BA delay in short children and adolescents.

Peak Growth Hormone Response to Combined Stimulation Test in 315 Children and Correlations with Metabolic Parameters

BACKGROUND/AIMS

Studies are lacking regarding the timing of peak growth hormone (PGH) response. We aim to elucidate the timing of PGH response to arginine and levodopa (A-LD) and evaluate the influence of body mass index (BMI) and other metabolic parameters on PGH.

METHODS

During growth hormone (GH) stimulation testing (ST) with A-LD, serum GH was measured at baseline and every 30 min up to 180 min. The PGH cut-off was defined as &amp;#x3c;10 ng/mL. IGF-1, IGF BP3, BMI, and metabolic parameters were obtained in a fasting state at baseline.

RESULTS

In the 315 tested children, stimulated PGH levels occurred at or before 120 min in 97.8% and at 180 min in 2.2%. GH area under the curve (AUC) positively correlated with PGH in all patients and with IGF-1 in pubertal males and females. BMI negatively correlated with PGH in all subjects. GH AUC negatively correlated with HOMA-IR and total cholesterol.

CONCLUSION

We propose termination of the GH ST with A-LD at 120 min since omission of GH measurement at 180 min did not alter the diagnosis of GH deficiency based on a cut-off of &amp;#x3c; 10 ng/mL. BMI should be considered in the interpretation of GH ST with A-LD. The relationships between GH AUC and metabolic parameters need further study.

Serum Metabolic Profiling Reveals the Antidepressive Effects of the Total Iridoids of Valeriana jatamansi Jones on Chronic Unpredictable Mild Stress Mice

Background

Depression is a long-term complex psychiatric disorder, and its etiology remains largely unknown. Valeriana jatamansi Jones ex Roxb (V. jatamansi) is used in the clinic for the treatment of depression, but there are insufficient reports of its antidepressive mechanisms and a poor understanding of its endogenous substance-related metabolism. The objective of this study was to identify biomarkers related to depression in serum samples and evaluate the antidepressive effects of the iridoid-rich fraction of V. jatamansi (IRFV) in a chronic unpredictable mild stress (CUMS) mouse model.

Methods

Here, CUMS was used to establish a mouse model of depression. Behavioral and biochemical indicators were investigated to evaluate the pharmacodynamic effects. A comprehensive serum metabolomics study by nuclear magnetic resonance (NMR) approach was applied to investigate the pharmacological mechanism of IRFV in CUMS mouse. Subsequently, we used multivariate statistical analysis to identify metabolic markers, such as principal component analysis (PCA) and orthogonal projection to latent structure with discriminant analysis (OPLS-DA), to distinguish between the CUMS mouse and the control group.

Results

After IRFV treatment, the immobility time, sucrose preference, and monoamine neurotransmitter were improved. PCA scores showed clear differences in metabolism between the CUMS group and control group. The PLS-DA or OPLS-DA model exhibited 26 metabolites as biomarkers to distinguish between the CUMS mice and the control mouse. Moreover, IRFV could significantly return 21 metabolites to normal levels.

Conclusion

The results confirmed that IRFV exerted an antidepressive effect by regulating multiple metabolic pathways, including the tricarboxylic acid cycle, the synthesis of neurotransmitters, and amino acid metabolism. These findings provide insights into the antidepressive mechanisms of IRFV.

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

This study investigated the relationship between peak stimulated growth hormone (GH) and body mass index (BMI), as well as the impact of BMI on therapeutic response in patients with GH deficiency (GHD). A total of 460 patients were enrolled in the study. The patients were divided into four groups as per the etiology and peak GH values: idiopathic (n = 439), organic (n = 21), complete (n = 114), and partial (n = 325) GHD groups. Subsequently, they were classified as normal, overweight, or obese based on their BMI. There was no difference in BMI between complete and partial GHD. A significant negative relationship between peak GH and BMI were found. Moreover, obese GHD children had a considerably better therapeutic response in height increase and BMI decrease during 2 years of GH treatment compared to non-obese children with GHD. There was no difference between peak GH and type of GH stimulation test (GHST), except the clonidine test, which showed a much lower peak GH in obese GHD children. In conclusion, BMI had a negative impact on peak GH response, and therapeutic outcome was more favorable in the obese group. Despite no difference in GH response by type of GHST, the degree of obesity differentially affected the results.

Challenges in the Diagnosis and Management of Growth Hormone Deficiency in India

In clinical practice, every year approximately 150,000 children are referred with short stature (SS) based on a cut-off of fifth percentile. The most important endocrine and treatable cause of SS is growth hormone deficiency (GHD). The lack of reliable data on the prevalence of GHD in India limits estimation of the magnitude of this problem. The diagnosis and treatment of GHD are hurdled with various challenges, restricting the availability of growth hormone (GH) therapy to only a very limited segment of the children in India. This review will firstly summarize the gaps and challenges in diagnosis and treatment of GHD based on literature analysis. Subsequently, it presents suggestions from the members at advisory board meetings to overcome these challenges. The advisory board suggested that early initiation of the therapy could better the chances of achieving final adult height within the normal range for the population. Education and awareness about growth disorders among parents, regular training for physicians, and more emphasis on using the Indian growth charts for growth monitoring would help improve the diagnosis and treatment of children with GHD. Availability of an easy-to-use therapy delivery system could also be beneficial in improving adherence and achieving satisfactory outcomes.

Revaluation of the clinical and metabolic behavior of children with isolated growth hormone deficiency during GH treatment according to newly proposed note 39 of the Italian Medicines Agency (AIFA)

PURPOSE

This study aimed at evaluating the clinical and metabolic behavior of children with isolated growth hormone (GH)-deficiency (GHD), grouped according to the new AIFA criteria for the appropriateness of use and reimbursement of GH treatment in children.

METHODS

The clinical and metabolic data of 310 prepubertal children (220 M, 90 F; mean age 10.8 years) grouped, according to new AIFA note 39, into Group A (No. 181 with a peak of GH <8 µg/l), Group B (No. 103 with a peak of GH ≥8 and <10 µg/l) and Group C (No. 26 with a peak of GH >10 µg/l) were retrospectively analyzed. Group A and B, diagnosed as having GHD, were treated with GH for at least 24 months, while Group C was analyzed only at baseline.

RESULTS

At baseline, Group A showed higher waist circumference than B (p = 0.031) and C (p = 0.041), while no difference in metabolic parameters was found between the three groups. After 12 and 24 months of treatment, Group B showed lower height velocity (p < 0.001 and p = 0.049, respectively) than Group A. As regards the metabolic parameters, both after 12 and 24 months of treatment, in Group B we found higher fasting glucose (p < 0.001 and p = 0.020), insulin (p = 0.002 and p = 0.011), Homa-β (p = 0.020 and p = 0.015) and Homa-IR (both p = 0.001) than Group A, with concomitant lower QUICKI (both p < 0.001) and HDL cholesterol (p = 0.020 and p = 0.011), without difference in other lipid parameters. The HbA1c levels, although always within the normal range, were found higher in Group B than Group A after 12 months (p = 0.015).

CONCLUSIONS

According to the new AIFA criteria, the reduction of GH cut-off for GHD diagnosis can be supported by auxological and metabolic data. The real benefits from GH therapy in children with higher stimulated GH levels at diagnosis remains to be better understand.

Hormone replacement therapy in children: The use of growth hormone and IGF-I

Recombinant human GH (rhGH) has been available since 1985. This article gives an overview, what has been achieved over the past 30 years in respect to optimization of rhGH treatment for the individual child with GH deficiency and what are the safety issues concerned with this treatment. In the last twenty years significant scientific progress has been made in the diagnosis of GH deficiency, the genetic disorders that are associated with pituitary GH deficiency and the genetics that influence growth in general. On the other hand rhGH is not only used in states of GH deficiency but also various conditions without a proven GH deficiency by classical standards. Clinical studies that investigated both the genetics of growth and the individual responses to rhGH therapy in these patient populations were able to refine our concept about the physiology of normal growth. In most patients under rhGH treatment there is a considerable short-term effect, however the overall gain in growth obtained by a long-term treatment until final height still remains a matter of debate in some of the conditions treated. Also first studies on the long-term safety risks of rhGH treatment have raised the question whether this treatment is similarly safe for all the patient groups eligible for such a treatment. Therefore even in the face of a longstanding safety record of this drug replacement therapy the discussion about the right cost and risk to benefit ratio is continuing. Consequently there is still a need for carefully conducted long-term studies that use modern anthropometric, genetic, and laboratory techniques in order to provide the necessary information for clinicians to select the patients that will benefit best from this valuable treatment without any long term risk.

Growth hormone responses to provocative tests in children with short stature

Growth hormone deficiency (GHD) is defined as a serum peak GH concentration <10 ng/mL with provocation as tested by a combination of at least two separate tests. The aim of this study was to compare two standard tests, insulin and levodopa (L-dopa), with a primary focus on specificity and accuracy. Clinical data were collected retrospectively from a review of 120 children who visited the pediatric endocrine clinic at Chonnam National University Hospital for the evaluation of short stature between January 2006 and April 2014. Subjects underwent GH provocation tests with insulin and L-dopa. Blood samples were obtained at 0, 15, 30, 45, 60, 90, and 120 min after administration, and GH levels were measured. In the insulin test, serial glucose levels were also checked, closely monitoring hypoglycemia. A total of 83 children (69.2%) were diagnosed with GHD and 37 children (30.8%) were diagnosed with idiopathic short stature (ISS). Peak GH levels were achieved an average of 45 min after the administration of insulin and L-dopa for both groups. The specificity and accuracy were 78.4% and 93.6% for the insulin test and 29.7% and 79.2% for L-dopa test, respectively. In the ISS group, the cumulative frequency of a GH cutoff value of >10 ng/mL at 120 min was 75.6% after insulin stimulation compared with 35.1% after L-dopa stimulation. Considering these results, we recommend performing the insulin test first to exclude ISS and then the L-dopa test for the diagnosis of GHD. This way, ISS patients are diagnosed after a single test, thus reducing hospital days and the burden of undergoing two serial tests.

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

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

Influence of body mass index on the growth hormone response to provocative testing in short children without growth hormone deficiency

Obesity and its related factors are known to suppress the secretion of growth hormone (GH). We aimed to evaluate the influence of body mass index (BMI) on the peak GH response to provocative testing in short children without GH deficiency. We conducted a retrospective review of medical records of 88 children (2-15 yr old) whose height was less than 3 percentile for one's age and sex, with normal results (peak GH level > 10 ng/mL) of GH provocative testing with clonidine and dopamine. Peak stimulated GH level, height, weight, pubertal status and serum IGF-1 level were measured. Univariate analysis showed that the BMI standard deviation score (SDS) correlated negatively with the natural log (ln) of the peak stimulated GH level (ln peak GH). BMI SDS did not correlate significantly with sex, age, pubertal status, or ln IGF-1 level. BMI SDS correlated negatively with ln peak GH level induced by clonidine but not by dopamine. In stepwise multivariate regression analysis, BMI SDS was the only significant predictor of ln peak GH level in the combination of tests and the clonidine test, but not in the dopamine test. In children without GH deficiency, BMI SDS correlates negatively with the peak GH level. BMI SDS should be included in the analysis of the results of GH provocation tests, especially tests with clonidine.

Diagnosis of growth hormone deficiency in childhood

PURPOSE OF REVIEW

The diagnosis of growth hormone deficiency (GHD) in childhood is challenging, in large part because of the lack of a true gold standard and the relatively poor performance of available diagnostic testing. This review discusses the recent literature on this topic.

RECENT FINDINGS

Auxology and clinical judgment remain the foundation for the diagnosis of GHD. Provocative growth hormone testing is poorly reproducible, dependent on factors such as body composition and pubertal status, and further limited by significant variability among commercially available growth hormone assays. Measurement of insulin-like growth factor I and insulin-like growth factor-binding protein 3 is not diagnostically useful in isolation but is helpful in combination with other diagnostic measures. Neuroimaging is also useful to inform diagnosis, as pituitary abnormalities suggest a higher likelihood of GHD persisting into adulthood. Although genetic testing is not routinely performed in the diagnosis of GHD at the present time, multiple recent reports raise the possibility that it may play a more important role in diagnosing GHD in the future.

SUMMARY

Beyond physicians' integrated assessment of auxology, clinical presentation, and bone age, current tools to diagnose GHD are suboptimal. Recent literature emphasizes the need to reappraise our current practice and to consider new tools for diagnosis.