Continuation of growth hormone (GH) therapy in GH-deficient patients during transition from childhood to adulthood: impact on insulin sensitivity and substrate metabolism

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.

Important Hormones Regulating Lipid Metabolism

There is a wide variety of kinds of lipids, and complex structures which determine the diversity and complexity of their functions. With the basic characteristic of water insolubility, lipid molecules are independent of the genetic information composed by genes to proteins, which determine the particularity of lipids in the human body, with water as the basic environment and genes to proteins as the genetic system. In this review, we have summarized the current landscape on hormone regulation of lipid metabolism. After the well-studied PI3K-AKT pathway, insulin affects fat synthesis by controlling the activity and production of various transcription factors. New mechanisms of thyroid hormone regulation are discussed, receptor α and β may mediate different procedures, the effect of thyroid hormone on mitochondria provides a new insight for hormones regulating lipid metabolism. Physiological concentration of adrenaline induces the expression of extrapituitary prolactin in adipose tissue macrophages, which promotes fat weight loss. Manipulation of hormonal action has the potential to offer a new therapeutic horizon for the global burden of obesity and its associated complications such as morbidity and mortality.

Approach to the Patient: Management of Pituitary Hormone Replacement Through Transition

Hypopituitarism in childhood is a rare, complex disorder that can present with highly variable phenotypes, which may continue into adult life. Pituitary deficits can evolve over time, with unpredictable patterns resulting in significant morbidity and mortality. Hypopituitarism and hypothalamic dysfunction may be associated with challenging comorbidities such as obesity, learning difficulties, behavioral issues, sleep disturbance, and visual impairment. Transition is the purposeful planned movement of adolescents and young adults with chronic conditions from child-centered to adult-oriented health care systems with a shift from parent- to patient-focused care. To achieve effective transition within a health care setting, the inherent challenges involved in the evolution from a dependent child to an independent adult must be recognized. Transition is a critical time medically for patients with hypopituitarism. Complex issues with respect to puberty, attainment of optimal stature, adherence to treatment, and acceptance of the need for life-sustaining medications need to be addressed. For health care professionals, transition is an opportunity for reassessment of the pituitary deficits and the need for lifelong replacement therapies, often against a background of complex psychological issues. We present 4 illustrative cases of hypopituitarism of differing etiologies with diverse clinical presentations. Diagnostic and management processes from clinical presentation to young adulthood are discussed, with a particular focus on needs and outcomes through transition.

Role of growth hormone in hepatic and intestinal triglyceride-rich lipoprotein metabolism

BACKGROUND

Elevated plasma concentrations of hepatic- and intestinally-derived triglyceride-rich lipoproteins (TRL) are implicated in the pathogenesis of atherosclerotic cardiovascular disease and all-cause mortality. Excess of TRL is the driving cause of atherogenic dyslipidemia commonly occurring in insulin-resistant individuals such as patients with obesity, type 2 diabetes and metabolic syndrome. Interestingly, growth hormone (GH)-deficient individuals display similar atherogenic dyslipidemia, suggesting an important role of GH and GH deficiency in the regulation of TRL metabolism.

OBJECTIVE

We aimed to examine the direct and/or indirect role of GH on TRL metabolism.

METHODS

We investigated the effect on fasting and postprandial hepatic-TRL and intestinal-TRL metabolism of short-term (one month) withdrawal of GH in 10 GH-deficient adults.

RESULTS

After GH withdrawal, we found a reduction in fasting plasma TRL concentration (significant decrease in TRL-TG, TRL-cholesterol, TRL-apoB-100, TRL-apoC-III and TRL-apoC-II) but not in postprandial TRL response. This reduction was due to fewer fasting TRL particles without a change in TG per particle and was not accompanied by a change in postprandial TRL-apoB-48 response. Individual reductions in TRL correlated strongly with increases in insulin sensitivity and decreases in TRL-apoC-III.

CONCLUSION

In this relatively short term 'loss of function' human experimental model, we have shown an unanticipated reduction of hepatic-TRL particles despite increase in total body fat mass and reduction in lean mass. These findings contrast with the atherogenic dyslipidemia previously described in chronic GH deficient states, providing a new perspective for the role of GH in lipoprotein metabolism.

Adult growth hormone deficiency: Optimizing transition of care from pediatric to adult services

OBJECTIVE

Most patients with childhood-onset growth hormone deficiency (CO-GHD) receive treatment with exogenous growth hormone (GH) to facilitate the attainment of their full potential adult height. Recent evidence suggests that continuing GH administration during the transition period between the end of linear growth and full adult maturity is necessary for proper body composition and bone and muscle health, and may also have beneficial effects on metabolic parameters, bone mineral density, and quality of life. The timing of this transition period coincides with the transfer of care from a pediatric to an adult endocrinologist, creating the potential for a care gap as a consequence of losing the patient to follow-up.

DESIGN

An advisory board comprising both pediatric and adult endocrinologists was assembled to address current clinical unmet needs and to collaborate on a structured transitional plan for optimal management of patients with CO-GHD.

INSIGHTS/CONCLUSION

The advisors suggest collaborative, multidisciplinary approaches to ensure continuity of care; ongoing testing and monitoring of GHD status into adulthood; and a clearly structured protocol that includes practical guidance for clinicians to establish best practices for transitioning older adolescents with persistent CO-GHD to adult care.

Effect of long-term growth hormone replacement on glucose metabolism in adults with growth hormone deficiency: a systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis was performed to summarize the long-term (more than 6 months) effect of growth hormone (GH) replacement therapy (GHRT) on glucose metabolism among adults growth hormone deficiency (AGHD) patients.

METHODS

We searched MEDLINE, EMBASE and the Cochrane Library databases from inception till March 2020 for relevant studies evaluating the effect of GHRT on glucose metabolism in AGHD patients. Results were stratified into two periods (6-12 months and more than12 months) according to the length of follow-up.

RESULTS

Thirty-three studies including 11 randomized controlled trials (RCTs) and 22 prospective open-label studies (POLs) were included in the meta-analysis. The findings of this meta-analysis showed that GH supplementation with a duration of 6-12 months among adults with growth hormone deficiency (GHD) significantly increased fasting plasma glucose (FPG) (SMD 0.37; 95% CI 0.25 to 0.49; I² = 0%; P < 0.00001), fasting insulin (FI) (SMD 0.2; 95% CI 0.08 to 0.33; I² = 9%; P = 0.001), glycated hemoglobin (HbA1c) (SMD 0.31; 95% CI 0.17 to 0.46; I² = 10%; P < 0.0001) and homeostasis model of assessment-insulin resistance (HOMA-IR) (SMD 0.28; 95% CI 0.08 to 0.47; I² = 13%; P = 0.006). Notably, GH intervention with a duration of more than 12 months showed no significant effect on FI (SMD 0.14; 95% CI - 0.09 to 0.37; I² = 0%; P = 0.24), HbA1c (SMD - 0.02; 95% CI - 0.3 to 0.26; I² = 72%; P = 0.89) and HOMA-IR levels (SMD 0.04; 95% CI - 0.24 to 0.31; I² = 0%; P = 0.80) in adults with GHD. However, FPG levels in AGHD were still significantly increased with more than one year intervention period (SMD 0.41; 95% CI 0.29 to 0.53; I² = 0%; P < 0.00001).

CONCLUSION

Overall, the current meta-analysis demonstrated that GHRT with a shorter duration (6-12 months) led to a deterioration in glucose metabolism including FPG, FI, HbA1c and HOMA-IR in AGHD patients. However, the negative effects of GH therapy on these glucose homeostasis parameters were not seen in longer duration of GHRT, except for FPG.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY GUIDELINES FOR MANAGEMENT OF GROWTH HORMONE DEFICIENCY IN ADULTS AND PATIENTS TRANSITIONING FROM PEDIATRIC TO ADULT CARE

Objective: The development of these guidelines is sponsored by the American Association of Clinical Endocrinologists (AACE) Board of Directors and American College of Endocrinology (ACE) Board of Trustees and adheres with published AACE protocols for the standardized production of clinical practice guidelines (CPG). Methods: Recommendations are based on diligent reviews of clinical evidence with transparent incorporation of subjective factors, according to established AACE/ACE guidelines for guidelines protocols. Results: The Executive Summary of this 2019 updated guideline contains 58 numbered recommendations: 12 are Grade A (21%), 19 are Grade B (33%), 21 are Grade C (36%), and 6 are Grade D (10%). These detailed, evidence-based recommendations allow for nuance-based clinical decision-making that addresses multiple aspects of real-world care of patients. The evidence base presented in the subsequent Appendix provides relevant supporting information for the Executive Summary recommendations. This update contains 357 citations of which 51 (14%) are evidence level (EL) 1 (strong), 168 (47%) are EL 2 (intermediate), 61 (17%) are EL 3 (weak), and 77 (22%) are EL 4 (no clinical evidence). Conclusion: This CPG is a practical tool that practicing endocrinologists and regulatory bodies can refer to regarding the identification, diagnosis, and treatment of adults and patients transitioning from pediatric to adult-care services with growth hormone deficiency (GHD). It provides guidelines on assessment, screening, diagnostic testing, and treatment recommendations for a range of individuals with various causes of adult GHD. The recommendations emphasize the importance of considering testing patients with a reasonable level of clinical suspicion of GHD using appropriate growth hormone (GH) cut-points for various GH-stimulation tests to accurately diagnose adult GHD, and to exercise caution interpreting serum GH and insulin-like growth factor-1 (IGF-1) levels, as various GH and IGF-1 assays are used to support treatment decisions. The intention to treat often requires sound clinical judgment and careful assessment of the benefits and risks specific to each individual patient. Unapproved uses of GH, long-term safety, and the current status of long-acting GH preparations are also discussed in this document. LAY ABSTRACT This updated guideline provides evidence-based recommendations regarding the identification, screening, assessment, diagnosis, and treatment for a range of individuals with various causes of adult growth-hormone deficiency (GHD) and patients with childhood-onset GHD transitioning to adult care. The update summarizes the most current knowledge about the accuracy of available GH-stimulation tests, safety of recombinant human GH (rhGH) replacement, unapproved uses of rhGH related to sports and aging, and new developments such as long-acting GH preparations that use a variety of technologies to prolong GH action. Recommendations offer a framework for physicians to manage patients with GHD effectively during transition to adult care and adulthood. Establishing a correct diagnosis is essential before consideration of replacement therapy with rhGH. Since the diagnosis of GHD in adults can be challenging, GH-stimulation tests are recommended based on individual patient circumstances and use of appropriate GH cut-points. Available GH-stimulation tests are discussed regarding variability, accuracy, reproducibility, safety, and contraindications, among other factors. The regimen for starting and maintaining rhGH treatment now uses individualized dose adjustments, which has improved effectiveness and reduced reported side effects, dependent on age, gender, body mass index, and various other individual characteristics. With careful dosing of rhGH replacement, many features of adult GHD are reversible and side effects of therapy can be minimized. Scientific studies have consistently shown rhGH therapy to be beneficial for adults with GHD, including improvements in body composition and quality of life, and have demonstrated the safety of short- and long-term rhGH replacement. Abbreviations: AACE = American Association of Clinical Endocrinologists; ACE = American College of Endocrinology; AHSG = alpha-2-HS-glycoprotein; AO-GHD = adult-onset growth hormone deficiency; ARG = arginine; BEL = best evidence level; BMD = bone mineral density; BMI = body mass index; CI = confidence interval; CO-GHD = childhood-onset growth hormone deficiency; CPG = clinical practice guideline; CRP = C-reactive protein; DM = diabetes mellitus; DXA = dual-energy X-ray absorptiometry; EL = evidence level; FDA = Food and Drug Administration; FD-GST = fixed-dose glucagon stimulation test; GeNeSIS = Genetics and Neuroendocrinology of Short Stature International Study; GH = growth hormone; GHD = growth hormone deficiency; GHRH = growth hormone-releasing hormone; GST = glucagon stimulation test; HDL = high-density lipoprotein; HypoCCS = Hypopituitary Control and Complications Study; IGF-1 = insulin-like growth factor-1; IGFBP = insulin-like growth factor-binding protein; IGHD = isolated growth hormone deficiency; ITT = insulin tolerance test; KIMS = Kabi International Metabolic Surveillance; LAGH = long-acting growth hormone; LDL = low-density lipoprotein; LIF = leukemia inhibitory factor; MPHD = multiple pituitary hormone deficiencies; MRI = magnetic resonance imaging; P-III-NP = procollagen type-III amino-terminal pro-peptide; PHD = pituitary hormone deficiencies; QoL = quality of life; rhGH = recombinant human growth hormone; ROC = receiver operating characteristic; RR = relative risk; SAH = subarachnoid hemorrhage; SDS = standard deviation score; SIR = standardized incidence ratio; SN = secondary neoplasms; T3 = triiodothyronine; TBI = traumatic brain injury; VDBP = vitamin D-binding protein; WADA = World Anti-Doping Agency; WB-GST = weight-based glucagon stimulation test.

Growth Hormone (GH) Therapy During the Transition Period: Should We Think About Early Retesting in Patients with Idiopathic and Isolated GH Deficiency?

To investigate growth hormone (GH) secretion at the transition age, retesting of all subjects who have undergone GH replacement therapy is recommended when linear growth and pubertal development are complete to distinguish between transitional and persistent GH deficiency (GHD). Early retesting of children with idiopathic and isolated GHD (i.e., before the achievement of final height and/or the adult pubertal stage) can avoid possible over-treatment. Here, we report data from our population with idiopathic and isolated GHD to encourage changes in the management and timing of retesting. We recruited 31 patients (19 males) with idiopathic GHD who received recombinant GH (rGH) for at least 2 years. All of the patients were retested at the transition age at least 3 months after rGH discontinuation. Permanent GHD was defined as a GH peak of <19 ng/mL after administration of growth hormone–releasing hormone (GHRH) + arginine as a provocative test. Permanent GHD was confirmed in only five of 31 patients (16.13%). None of these patients presented low serum insulin-like growth factor (IGF)-1 levels (<−2 standard deviation score (SDS)). Only one male patient with an IGF-1 serum level lower than −2 SDS showed a normal GH stimulation response, with a GH peak of 44.99 ng/mL. Few patients with idiopathic and isolated GHD demonstrated persistence of the deficit when retested at the transition age, suggesting that the timing of retesting should be anticipated to avoid overtreatment.

Childhood-onset growth hormone deficiency and the transition to adulthood: current perspective

Childhood-onset growth hormone deficiency (CO-GHD) is an endocrine condition associated with a broad range of health issues from childhood through to adulthood, which requires particular attention during the transition period from adolescence to young adulthood. There is uncertainty in the clinical practice of the management of CO-GHD during transition regarding the clinical assessment and management of individual patients during and after transition to obtain optimal follow-up and improved health outcomes. Despite the availability of clinical guidelines providing the framework for transition of young adults with CO-GHD, there remains substantial variation in approaching transitional care among pediatric and adult services. A well-structured and coordinated transitional plan with clear communication and direct collaboration between pediatric and adult health care to ensure optimal management of adolescents with CO-GHD during transition is needed.

THERAPY OF ENDOCRINE DISEASE: Growth hormone replacement therapy in adults: 30 years of personal clinical experience

The acute metabolic actions of purified human growth hormone (GH) were first documented in adult hypopituitary patients more than 50 years ago, and placebo-controlled long-term GH trials in GH-deficient adults (GHDA) surfaced in 1989 with the availability of biosynthetic human GH. Untreated GHDA is associated with excess morbidity and mortality from cardiovascular disease and the phenotype includes fatigue, reduced aerobic exercise capacity, abdominal obesity, reduced lean body mass, osteopenia and elevated levels of circulating cardiovascular biomarkers. Several of these features reverse and normalize with GH replacement. It remains controversial whether quality of life, assessed by questionnaires, improves. The known side effects are fluid retention and insulin resistance, which are reversible and dose dependent. The dose requirement declines markedly with age and is higher in women. Continuation of GH replacement into adulthood in patients with childhood-onset disease is indicated, if the diagnosis is reconfirmed. GH treatment of frail elderly subjects without documented pituitary disease remains unwarranted. Observational data show that mortality in GH-replaced patients is reduced compared to untreated patients. Even though this reduced mortality could be due to selection bias, GH replacement in GHDA has proven beneficial and safe.

Comparison between euglycemic hyperinsulinemic clamp and surrogate indices of insulin sensitivity in children with growth hormone deficiency

OBJECTIVE

Data about the impact of growth hormone treatment (GHT) on insulin sensitivity in children are quite controversial, due to the different surrogate indices that have been used.

DESIGN

We evaluated insulin sensitivity through the euglycemic hyperinsulinemic clamp, considered the gold standard technique, in 23 children affected by growth hormone deficiency (GHD) at baseline and after 12months of GHT and in 12 controls with short stature at baseline, and we compared the clamp-derived index (M-value) with the most commonly used surrogate index of insulin sensitivity, as ISI Matsuda, and with circulating plasma markers of insulin sensitivity, as adiponectin and resistin levels.

RESULTS

At baseline, no significant difference in all metabolic parameters between GHD children and control subjects was found. After 12months of GHT, GHD children showed a significant increase in fasting insulin (p<0.001) and resistin (p=0.028) and a decrease in ISI Matsuda (p<0.001) and M-value (p<0.001), without significant change in fasting glucose, HbA1c and adiponectin. In GHD children, M-value showed a significant but weak correlation with ISI Matsuda (rho 0.418, p=0.047) at baseline, while no correlation with other parameters was found. After 12months of GHT, M-value did not show any significant correlation with any other metabolic parameter analyzed.

CONCLUSIONS

This study highlights the limit of the evaluation of insulin sensitivity performed through surrogate indices or circulating markers, which may lead to controversial data and do not correlate with the gold standard technique to evaluate insulin sensitivity.

Glucose Metabolism in Children With Growth Hormone Deficiency

BACKGROUND

The growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis has a fundamental impact on glucose metabolism. Therefore, both untreated GH deficiency (GHD) and GH treatment (GHT) may be associated with some metabolic alterations, although the abnormalities of glucose metabolism have been investigated by relatively few studies as main outcomes.

AIM

The present review summarizes the available data on glucose metabolism in children with GHD, providing an overview of the current state of the art in order to better clarify the real metabolic impact of GHD and GHT.

METHODS

Among all the existing studies, we evaluated all original studies that fulfilled our criteria for analysis reporting parameters of glucose metabolism as the primary or secondary objective.

RESULTS

The reported impact of GHD per se on glucose metabolism is quite homogeneous, with the majority of studies reporting no significant difference in metabolic parameters between GHD children and controls. Conversely, GHT proves to be more frequently associated with a subtle form of insulin resistance, while both fasting glucose and HbA1c levels remain almost always within the normal range.

CONCLUSION

The different methods to study glucose metabolism, the heterogeneity of the populations evaluated, the different doses of GH used together with the variable duration of follow-up may be responsible for discrepancy in the results. Long-term longitudinal studies having glucose homeostasis as their primary outcome are still needed in order better to clarify the real metabolic impact of GHD and GHT in children.

Incidence of diabetes mellitus and neoplasia in Japanese short-statured children treated with growth hormone in the Genetics and Neuroendocrinology of Short Stature International Study (GeNeSIS)

The primary goal of the Genetics and Neuroendocrinology of Short Stature International Study (GeNeSIS) was to assess the safety and effectiveness of Humatrope^®, a GH preparation, in the treatment of pediatric patients with short stature. We report our findings in the GH-treated Japanese pediatric population focusing on the incidence of type 2 diabetes (T2D) and occurrence of neoplasms. A total of 2,345 Japanese patients were assessed for safety. During a mean observation period of 3.2 yr, T2D occurred in 3 patients (0.13%) and slowly progressive insulin-dependent diabetes mellitus (SPIDDM) related to underlying mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) in 1 patient (0.04%). Neoplasms were reported in 13 patients (0.56%), including 1 patient with brain tumor (germinoma) and 5 with craniopharyngiomas (4 recurrences); the remainder were benign, typically dermatological, neoplasms. The incidence of diabetes mellitus determined in the study did not differ from previous reports in GH-treated pediatric patients, and there was no apparent increase in the risk of new neoplastic lesions or malignant tumors.

Impact of discontinuation of growth hormone treatment on lipids and weight status in adolescents

BACKGROUND

While the main role of growth hormone (GH) replacement therapy in children is to promote linear growth, GH has also an effect on lipids and body composition. There is an ongoing discussion whether discontinuation of GH treatment is associated with deterioration of lipids.

METHODS

We analyzed weight status [as body mass index-standard deviation score (BMI-SDS)], insulin like growth factor (IGF)-1, triglycerides, total, low-density liporptoein (LDL)- and high-density lipoprotein (HDL)-cholesterol at the end of GH treatment and in mean 6 months later in 90 adolescents (53 with GH deficiency, 16 with Turner syndrome [TS] and 21 born small-for-gestational age [SGA]).

RESULTS

After stopping GH treatment, total cholesterol (+10±24 mg/dL vs. -4±13 mg/dL) and LDL-cholesterol (+15±20 mg/dL vs. -6±12 mg/dL) increased significantly higher in severe (defined by GH peak in stimulation test <3 ng/mL) compared to moderate GHD. In patients with TS, total cholesterol (+19±9 mg/dL), LDL-cholesterol (+9±12 mg/dL) and HDL-cholesterol (+4.3±3.5 mg/dL) increased significantly. In adolescents born SGA, triglycerides increased (+34±51 mg/dL) and HDL-cholesterol decreased significantly (-3.8±7.1 mg/dL). In multiple linear regression analyses, changes of total and LDL-cholesterol were significantly negatively related to peak GH in stimulation tests, but not to gender, age at GH start, duration of GH treatment, observation time, changes of BMI-SDS or IGF-1 after the end of GH treatment. The BMI-SDS did not change after the end of GH treatment.

CONCLUSIONS

Discontinuation of GH treatment leads to a deterioration of lipids in TS, SGA and severe but not moderate GHD.

Growth hormone deficiency during young adulthood and the benefits of growth hormone replacement

Until quite recently, the management of children with growth hormone deficiency (GHD) had focussed on the use of recombinant human GH (rhGH) therapy to normalise final adult height. However, research over the past two decades that has demonstrated deficits in bone health and cardiac function, as well as impaired quality of life in adults with childhood-onset GHD (CO-GHD), has questioned this practice. Some of these studies suggested that there may be short-term benefits of rhGH in certain group of adolescents with GHD during transition, although the impact of GHD and replacement during the transition period has not been adequately investigated and its long-term benefits remain unclear. GH therapy remains expensive and well-designed long-term studies are needed to determine the cost effectiveness and clinical benefit of ongoing rhGH during transition and further into adulthood. In the absence of compelling data to justify widespread continuation of rhGH into adult life, there are several questions related to its use that remain unanswered. This paper reviews the effects of growth hormone deficiency on bone health, cardiovascular function, metabolic profile and quality of life during transition and young adulthood.

Stories of experiences of care for growth hormone deficiency: the CRESCERE project

AIMS

Growth hormone deficiency therapy is demanding for patients and caregivers. Teams engaged in the clinical management of growth hormone deficiency therapy need to know how families live with this condition, to provide an adequate support and prevent the risk of withdrawal from therapy.

METHODS

Using Narrative Medicine, testimonies from patients, their parents and providers of care were collected from 11 Italian centers. Narrations were analyzed throughout an elaboration of recurring words and expressions.

RESULTS

Although care management and outcomes were considered satisfying in the 182 collected narratives, recurring signals of intolerance among adolescents and the worry of not being well informed about side effects among parents are open issues.

CONCLUSION

Narratives found that communication issues could decrease adherence and influence the physicians' clinical practice.

Effects of growth hormone (GH) therapy withdrawal on glucose metabolism in not confirmed GH deficient adolescents at final height

CONTEXT OBJECTIVE

Growth hormone deficiency (GHD) is associated with insulin resistance and diabetes, in particular after treatment in children and adults with pre-existing metabolic risk factors. Our aims were. i) to evaluate the effect on glucose metabolism of rhGH treatment and withdrawal in not confirmed GHD adolescents at the achievement of adult height; ii) to investigate the impact of GH receptor gene genomic deletion of exon 3 (d3GHR).

DESIGN SETTING

We performed a longitudinal study (1 year) in a tertiary care center.

METHODS

23 GHD adolescent were followed in the last year of rhGH treatment (T0), 6 (T6) and 12 (T12) months after rhGH withdrawal with fasting and post-OGTT evaluations. 40 healthy adolescents were used as controls. HOMA-IR, HOMA%β, insulinogenic (INS) and disposition (DI) indexes were calculated. GHR genotypes were determined by multiplex PCR.

RESULTS

In the group as a whole, fasting insulin (p<0.05), HOMA-IR (p<0.05), insulin and glucose levels during OGTT (p<0.01) progressively decreased from T0 to T12 becoming similar to controls. During rhGH, a compensatory insulin secretion with a stable DI was recorded, and, then, HOMAβ and INS decreased at T6 and T12 (p<0.05). By evaluating the GHR genotype, nDel GHD showed a decrease from T0 to T12 in HOMA-IR, HOMAβ, INS (p<0.05) and DI. Del GHD showed a gradual increase in DI (p<0.05) and INS with a stable HOMA-IR and higher HDL-cholesterol (p<0.01).

CONCLUSIONS

In not confirmed GHD adolescents the fasting deterioration in glucose homeostasis during rhGH is efficaciously coupled with a compensatory insulin secretion and activity at OGTT. The presence of at least one d3GHR allele is associated with lower glucose levels and higher HOMA-β and DI after rhGH withdrawal. Screening for the d3GHR in the pediatric age may help physicians to follow and phenotype GHD patients also by a metabolic point of view.

The Challenge of Growth Hormone Deficiency Diagnosis and Treatment during the Transition from Puberty into Adulthood

In children with childhood-onset growth hormone deficiency, replacement GH therapy is effective in normalizing height during childhood and achieving adult height within the genetic target range. GH has further beneficial effects on body composition and metabolism through adult life. The transition phase, defined as the period from mid to late teens until 6-7 years after the achievement of final height, represents a crucial time for reassessing children's GH secretion and deciding whether GH therapy should be continued throughout life. Evidence-based guidelines for diagnosis and treatment of growth hormone deficient children during transition are lacking. The aim of this review is to critically review the up-to-date evidence on the best management of transition patients in order to ensure the correct definitive diagnosis and establish the appropriate therapeutic regimen.

Cardiovascular risk, cardiac function, physical activity, and quality of life with and without long-term growth hormone therapy in adult survivors of childhood acute lymphoblastic leukemia

CONTEXT

Long-term data are missing in GH-treated acute lymphoblastic leukemia (ALL) patients. GH therapy may result in poorer outcome regarding cardiovascular (CV) and particularly cardiac effects than in patients with hypothalamic-pituitary disease.

OBJECTIVE

Our objective was to evaluate GH therapy on CV risk, cardiac function, physical activity, and quality of life in ALL patients treated with cranial radiotherapy (18-24 Gy) and chemotherapy (anthracycline dose 120 mg/m2).

DESIGN AND SETTING

We conducted a 5- and 8-yr open nonrandomized prospective study in a university hospital clinic.

STUDY PARTICIPANTS

Two groups of GH-deficient ALL patients (aged 25 yr; range 19-32 yr) and matched population controls participated.

INTERVENTIONS

One ALL group (n=16) received GH for 5 yr, and the other ALL group (n=13) did not receive GH therapy.

MAIN OUTCOME MEASURES

We evaluated the prevalence of CV risk factors and metabolic syndrome (International Diabetes Federation consensus), cardiac function (echocardiography), and quality of life and physical activity questionnaires.

RESULTS

In comparison with 8 yr without, 5 yr with GH therapy resulted in significant positive changes in plasma glucose (-0.5 vs. 0.6 mmol/liter, P=0.002), apolipoprotein B/apolipoprotein A1 ratio (-0.1 vs. 0.0, P=0.03), and high-density lipoprotein-cholesterol (0.20 vs.-0.01 mmol/liter, P=0.008) and a significant reduction in the prevalence of metabolic syndrome (P=0.008). No significant difference in the left-ventricular systolic function or in physical activity and quality of life was recorded before and after 5 or 8 yr, respectively (all P>0.3).

CONCLUSION

GH therapy reduced the CV risk in this young ALL population but resulted in no clear benefit or deterioration in cardiac function.

Growth hormone: health considerations beyond height gain

The therapeutic benefit of growth hormone (GH) therapy in improving height in short children is widely recognized; however, GH therapy is associated with other metabolic actions that may be of benefit in these children. Beneficial effects of GH on body composition have been documented in several different patient populations as well as improvements in lipid profile. Marked augmentation of bone mineral density also seems evident in many pediatric populations. Some of these benefits may require continued therapy past the acquisition of adult height. With long-term therapy of any kind, the adverse consequences of treatment should also be considered. Fortunately, long-term GH treatment seems to be safe and well-tolerated. This review describes the long-term metabolic effects of GH treatment in the pediatric population and considers how these may benefit children who are treated with GH.

[Congenital adrenal hyperplasia and growth hormone deficiency. Special care in transition to adulthood]

Children with chronically endocrine diseases should be treated as young adults by adult endocrinologists. To optimize the transfer from the pediatric to adult endocrinologist, the model of a common transition clinic has been developed. Within this setting it should be possible to exchange experiences, extend the knowledge and understanding of the disease with the other side, and to provide for the patient an optimal outpatient care. This model, however, has only been sporadically realized to date. To set an example for the problems of the transition into adult endocrinology, we used two different endocrine diseases, the classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency, and the childhood-onset growth hormone deficiency. Specific problems for this transfer to adult care are the fixation of the patients to their pediatricians and the lack of comprehension in the need of a long term and continuous therapy. The consequence is a dramatic impairment in the quality of the therapy.

Effects of growth hormone on glucose, lipid, and protein metabolism in human subjects

In evolutionary terms, GH and intracellular STAT 5 signaling is a very old regulatory system. Whereas insulin dominates periprandially, GH may be viewed as the primary anabolic hormone during stress and fasting. GH exerts anabolic effects directly and through stimulation of IGF-I, insulin, and free fatty acids (FFA). When subjects are well nourished, the GH-induced stimulation of IGF-I and insulin is important for anabolic storage and growth of lean body mass (LBM), adipose tissue, and glycogen reserves. During fasting and other catabolic states, GH predominantly stimulates the release and oxidation of FFA, which leads to decreased glucose and protein oxidation and preservation of LBM and glycogen stores. The most prominent metabolic effect of GH is a marked increase in lipolysis and FFA levels. In the basal state, the effects of GH on protein metabolism are modest and include increased protein synthesis and decreased breakdown at the whole body level and in muscle together with decreased amino acid degradation/oxidation and decreased hepatic urea formation. During fasting and stress, the effects of GH on protein metabolism become more pronounced; lack of GH during fasting increases protein loss and urea production rates by approximately 50%, with a similar increase in muscle protein breakdown. GH is a counterregulatory hormone that antagonizes the hepatic and peripheral effects of insulin on glucose metabolism via mechanisms involving the concomitant increase in FFA flux and uptake. This ability of GH to induce insulin resistance is significant for the defense against hypoglycemia, for the development of "stress" diabetes during fasting and inflammatory illness, and perhaps for the "Dawn" phenomenon (the increase in insulin requirements in the early morning hours). Adult patients with GH deficiency are insulin resistant-probably related to increased adiposity, reduced LBM, and impaired physical performance-which temporarily worsens when GH treatment is initiated. Conversely, despite increased LBM and decreased fat mass, patients with acromegaly are consistently insulin resistant and become more sensitive after appropriate treatment.

Metabolic effects of growth hormone (GH) replacement in children and adolescents with severe isolated GH deficiency due to a GHRH receptor mutation

BACKGROUND

The interpretation of the true effect of GH replacement therapy (GHRT) on metabolic status in GH deficiency (GHD) is often complicated by differing aetiologies of GHD and by the presence of additional hormone deficits.

OBJECTIVE

To study the growth and response of the lipid profile and body composition to GHRT in a cohort of children with the same mutation in the GHRH receptor gene. Design Nine GH-deficient subjects (mean age 12.8 years, range 5-17.5 years; three male) in a rural community in Northeast Brazil were treated with GHRT for 2 years and compared with indigenous normal controls.

MAIN OUTCOME MEASURES

Total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), triglycerides (TG) and body composition were measured at baseline and after 3, 12 and 24 months of GHRT.

RESULTS

At baseline, the subjects with GHD had an adverse lipid profile, including elevated TC, elevated LDL-C and elevated TG. GHRT normalized TG in 3 months, LDL-C in 12 months and TC in 24 months. At baseline, older pubertal subjects with GHD had adverse body composition, including higher percentage fat mass (%FM), and GHRT induced a reduction in %FM that was maintained after 24 months. By contrast, younger prepubertal subjects did not have an adverse body composition.

CONCLUSIONS

Lipid profile was abnormal at baseline, while abnormal body composition was only seen in older subjects in late puberty, indicating that body composition is less sensitive to the effect of GHD than lipid profile. GHRT improves lipid profile at all ages, while it affects body composition only towards the end of growth, emphasizing its importance in achieving normal somatic development in the transition period.

Limited efficacy of growth hormone (GH) during transition of GH-deficient patients from adolescence to adulthood: a phase III multicenter, double-blind, randomized two-year trial

CONTEXT

Treatment of GH-deficient adolescents in transition to adulthood remains challenging.

OBJECTIVE

The objective was to assess the safety and efficacy of GH in GH-deficient adolescents in transition.

PATIENTS

Fifty-eight GH-deficient adolescents (mean age, 15.8 +/- 1.8 yr; 33 males) at near completion of their linear growth participated in the study.

INTERVENTION

Baseline studies were done while subjects were on GH. Subjects were retested (insulin-induced hypoglycemia) 4 wk after GH discontinuation and reclassified as persistently GH-deficient or controls (n = 18). GH-deficient subjects were randomized to GH (n = 25, approximately 20 microg/kg.d) or placebo (n = 15).

SETTING

The multicenter study was conducted over a 2-yr period.

MAIN OUTCOMES

Changes in body composition, bone mineral density (BMD), quality of life (QOL), cardiovascular and metabolic markers were measured.

RESULTS

All groups had normal measures of lipid and carbohydrate metabolism, body composition, BMD, cardiac function, muscle strength, and QOL at baseline and after 2 yr. IGF-I concentrations decreased in all, but less so in the GH-group (P = 0.013). There was a greater increase in lean body mass (lesser adiposity) in the GH group than placebo at 12 months, but not at 24 months.

CONCLUSIONS

1) GH-deficient patients properly treated in childhood can have normal BMD, body composition, cardiac function, muscle strength, carbohydrate and lipid metabolism, and QOL when reaching adult height; and 2) continuation of GH therapy for 2 yr did not change these measures as compared to placebo-treated or control subjects. GH-deficient adolescents in good metabolic status at the time of epiphyseal fusion may safely discontinue GH for at least 2 yr. Follow-up is needed to determine whether GH therapy is eventually warranted in subjects treated with GH during childhood.

Somatropin and glucose homeostasis: considerations for patient management

More than 60 years ago it was shown, in dogs, that anterior pituitary extracts may cause glucose intolerance and that hypophysectomy was associated with increased insulin sensitivity. Accordingly, active acromegaly is characterized by insulin resistance at the hepatic and muscular level, whereas children with growth hormone (GH) deficiency are insulin hypersensitive and prone to developing fasting hypoglycemia. Somewhat unexpectedly, hypopituitary adults with untreated GH deficiency tend to be insulin resistant, which may be aggravated by somatropin (GH) therapy. The explanation for this apparent paradox has not been fully established. It is, however, likely that high circulating levels of free fatty acids (FFA) are responsible for insulin resistance, both before and after somatropin therapy. In the untreated state, patients have abdominal obesity, which increases circulating FFA levels. Since GH has potent lipolytic effects, somatropin therapy will further increase FFA levels. Theoretically, this GH replacement effect will eventually be compensated for by favorable alterations in body composition, including a reduction of fat mass. Subcutaneous somatropin therapy, however, will cause some degree of hypersomatropinemia in the prandial phase, which will inevitably antagonize the physiologic effects of insulin. At present, the best way to circumvent this inherent problem is to employ evening injections of somatropin and to ensure that the dosage is not too high. In the latter regard, it is important to realize that dosage requirements are lower in adults compared with children, and that the dosage will probably need to be reduced with age in the individual patient.

Growth hormone deficiency and related disorders: insights into causation, diagnosis, and treatment

Advances in molecular biology have led to the identification of mutations within several novel genes associated with the phenotype of isolated growth hormone deficiency, combined pituitary hormone deficiency, and syndromes such as septo-optic dysplasia. Progress has also been made in terms of the optimum diagnosis of disorders of stature and their treatment. The use of growth hormone for the treatment of adults with growth hormone deficiency and conditions such as Turner's syndrome, Prader-Willi syndrome, intrauterine growth restriction, and chronic renal failure has changed the practice of endocrinology, although cost-benefit implications remain to be established.

Long-Term Efficacy and Safety of Somatropin for Adult Growth Hormone Deficiency

The beneficial effects of somatropin (growth hormone [GH] replacement therapy) in adults are now established. Long-term somatropin administration in GH-deficient adults improves body composition, muscle strength, quality of life, bone mass and density, and lipoprotein pattern. The extent to which somatropin therapy can also reduce cardiovascular morbidity and mortality in GH-deficient adults remains to be determined. By starting with a low dose of somatropin, which is gradually increased based on clinical response (body composition, well-being, and serum insulin-like growth factor-1 concentration), effective treatment can be achieved with a minimum of fluid-related adverse effects. Thorough long-term monitoring of glucose metabolism, cardiovascular measurements, and underlying pituitary disease, is, however, mandatory.

Growth hormone therapy and its relationship to insulin resistance, glucose intolerance and diabetes mellitus: a review of recent evidence

It is widely recommended that consideration should be given to the therapeutic use of growth hormone (GH) in adults with GH deficiency, whether the condition is of childhood or adult onset. One reason for this recommendation is the possibility that such treatment may reduce the excess cardiovascular risk which is associated with hypopituitarism. This excess risk has been well documented, with mortality ratios of 1.7 to 2.2 being quoted in different studies, and may be a result of the insulin resistance which occurs in hypopituitarism. However, it has also been suggested that this insulin resistance may itself be the result of GH deficiency, especially as GH deficiency is accompanied by suggestive morphological features such as central adiposity. There is, however, no direct evidence that the increase in cardiovascular risk in hypopituitarism is the result of GH deficiency, and the only prospective study designed to examine the relationship failed to find a statistically significant correlation between the two. Since GH administration may also have an independent adverse effect on insulin sensitivity and could thus cause a theoretical worsening of cardiovascular risk, it is important to review the observed effects of GH administration on carbohydrate metabolism in practice. Interpretation of the literature is made difficult by many confounding factors, including differences in study duration, biochemical tools adopted, the use of selected populations and the dose-dependent effect of GH on synthesis of insulin- like growth factor-1. One of the most sensitive markers of a deterioration in insulin sensitivity is the serum insulin level. A rise in serum insulin (fasting, or post-glucose load) was reported in all studies in which it was measured. The majority of studies have also reported a rise in fasting blood glucose. A smaller proportion of reports noted an associated increase in postprandial glucose and in glycosylated haemoglobin (HbA(1c)) while a few reported new cases of either impaired glucose tolerance or frank diabetes mellitus. In general, however, the observed deterioration in insulin sensitivity was small and increases which occurred in blood glucose were small. Nevertheless, these data indicate that rather than lead to an improvement in insulin resistance in hypopituitarism, GH treatment may actually make it worse. As it is also known that even minor reductions in insulin sensitivity may be associated with a clinically significant increase in cardiovascular risk, further large-scale controlled trials are required before the efficacy and safety of GH treatment of adults can be established.

Optimizing gh therapy in adults and children

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