A 10-year, prospective study of the metabolic effects of growth hormone replacement in adults

Exploring the sex difference in cardiovascular risk during growth hormone therapy in adults

OBJECTIVE

Given the previously identified sex differences in cardiovascular (CV) morbidity and mortality in patients with growth hormone deficiency (GHD) receiving GH replacement therapy (GHRT), our aim is to investigate sex-specific differences in the efficacy of (long-term) GHRT on CV risk profile and disease in subjects with GHD. Our hypothesis is that women will experience less beneficial effects than men.

DESIGN

Retrospective nationwide cohort study.

METHODS

We compared all men (n = 1335) and women (n = 1251) with severe GHD registered in the Dutch National Registry of GH Treatment in Adults database with respect to CV risk profile and morbidity at baseline and during follow-up.

RESULTS

Men had a more unfavourable CV risk profile at baseline. During the first years of GHRT, the reduction in waist circumference, waist-to-hip ratio, total cholesterol, and triglyceride levels was greater in men than in women (all P < .05). Between-sex differences in effects during later follow-up were less clear. No sex differences were found in the risk of developing non-fatal cardiovascular or cerebrovascular diseases during GHRT.

CONCLUSIONS

Our results suggest that men with GHD did indeed experience more beneficial effects of GHRT on body composition and lipoprotein metabolism than women, at least in the early years of treatment. Also, the more unfavourable CV risk profile at baseline in men did not translate into a sex difference in the risk of developing CV and cerebrovascular morbidity during GHRT.

[Unfavourable cardiovascular consequences of adult growth hormone deficiency]

The growth hormone-insulin-like growth factor-1 (GH-IGF-1) axis plays a crucial role in maintaining the normal function of the cardiovascular system. Results of the last decades demonstrated that GH-IGF-1 takes part in regulating peripheral resistance and contributes to preserving physiological cardiac mass and left ventricular function. Vasculoprotective functions of the GH-IGF-1 axis are believed to counteract atherosclerosis. Unlike in childhood, when GH-deficiency results in growth retardation, GH deficiency does not cause specific symptoms in adults. Adult growth hormone deficiency (AGHD) is characterized by a clustering of cardiometabolic risk factors resulting in a clinical picture similar to the metabolic syndrome. Besides visceral obesity, dyslipidemia and insulin resistance, novel cardiovascular risk factors, such as chronic low-grade inflammation, oxidative stress and prothrombotic state have also been reported in AGHD and may contribute to the increased cardiometabolic risk. Based on a growing body of evidence, long-term GH-replacement improves lipid profile significantly and has a favorable impact on body composition, endothelial function, left ventricular mass as well as the novel, non-traditional cardiometabolic risk factors. Increased mortality associated with the disease is now considered to be multicausal and as such cannot be solely attributed to the GH-deficiency. The etiology of GH-deficiency, treatment of the underlying pathology as well as the inadequate treatment of coexisting hormonal deficiencies might also be responsible for the increased mortality. Nevertheless, in hypopituitarism, adequate replacement therapy including GH-substitution may result in a mortality that is comparable to the general population. Orv Hetil. 2023; 164(41): 1616-1627.

The Impact of Westernization on the Insulin/IGF-I Signaling Pathway and the Metabolic Syndrome: It Is Time for Change

The metabolic syndrome is a cluster of overlapping conditions resulting in an increased incidence of type 2 diabetes, cardiovascular disease, and cancer. In the last few decades, prevalence of the metabolic syndrome in the Western world has reached epidemic proportions and this is likely due to alterations in diet and the environment as well as decreased physical activity. This review discusses how the Western diet and lifestyle (Westernization) has played an important etiological role in the pathogenesis of the metabolic syndrome and its consequences by exerting negative effects on activity of the insulin-insulin-like growth factor-I (insulin-IGF-I) system. It is further proposed that interventions that normalize/reduce activity of the insulin-IGF-I system may play a key role in the prevention and treatment of the metabolic syndrome. For successful prevention, limitation, and treatment of the metabolic syndrome, the focus should be primarily on changing our diets and lifestyle in accordance with our genetic make-up, formed in adaptation to Paleolithic diets and lifestyles during a period of several million years of human evolution. Translating this insight into clinical practice, however, requires not only individual changes in our food and lifestyle, starting in pediatric populations at a very young age, but also requires fundamental changes in our current health systems and food industry. Change is needed: primary prevention of the metabolic syndrome should be made a political priority. New strategies and policies should be developed to stimulate and implement behaviors encouraging the sustainable use of healthy diets and lifestyles to prevent the metabolic syndrome before it develops.

Reduced CV risk with long-term GH replacement in AGHD: data from two large observational studies

Adult growth hormone deficiency (AGHD) is associated with an increased risk of cardiovascular (CV) disease. Long-term growth hormone (GH) treatment could improve CV outcomes. The objective of this study was to evaluate CV disease risk in patients with AGHD who received GH replacement therapy for up to 10 years as part of NordiNet® IOS (NCT00960128) and the ANSWER Program (NCT01009905). The studies were observational, non-interventional and multicentre, monitoring long-term effectiveness and safety of GH treatment. NordiNet® IOS involved 23 countries (469 sites) across Europe and the Middle East. The ANSWER Program was conducted in the USA (207 sites). This analysis included patients aged 18-75 years who were GH naïve at study entry, who had ≤10 years of GH treatment data and who could be assessed for CV risk for at least 1 follow-up year. The main outcome measure was risk of CV disease by age 75 years, as calculated with the Multinational Cardiovascular Risk Consortium model (Brunner score) using non-high-density lipoprotein cholesterol adjusted for age, sex and CV risk factors. The results of this analysis showed that CV risk decreased gradually over the 10-year period for GH-treated patients. The risk was lower for patients treated for 2 and 7 years vs age- and sex-matched control groups (not yet started treatment) (14.51% vs 16.15%; P = 0.0105 and 13.53% vs 16.81%; P = 0.0001, respectively). This suggests that GH treatment in people with AGHD may reduce the risk of CV disease by age 75 years compared with matched controls.

Effects of 18 months of GH replacement on cardiovascular risk factors and quality of life in GH deficient adults; a randomized controlled trial using a fixed very low and a standard dose of GH

OBJECTIVE

Little is known of the effects of a fixed very low dose of growth hormone (GH) replacement on cardiovascular risk factors, bone mass, muscle strength and quality of life (QoL) in hypopituitary patients.

DESIGN/PATIENTS/METHODS

This was an open-label randomized study performed at a single center. Consecutive hypopituitary patients with adult onset GH deficiency (GHD) and BMI ≥ 27 kg/m² were randomized to receive a very low fixed dose of GH (LG, n = 9) or a standard dose of GH (SG, n = 9). Body composition, glucose and lipid metabolism, bone mineral content (BMC) and density (BMD), muscle strength, and QoL were measured at baseline and after 6, 12 and 18 months.

RESULTS

The fixed GH dose in LG was 0.1 mg/day. In SG, the mean baseline GH dose of 0.13 mg/day was gradually increased to 0.31 mg/day at study end. Lean body mass (LBM) as measured using DEXA as well as total body water (TBW) and extracellular water (ECW) were increased only in SG (P < 0.01, P < 0.05, and P < 0.01 vs. LG, respectively). There were no between-groups differences in BMD, BMC, insulin sensitivity, lipids, or muscle strength. Finally, although not significant compared with SG, a sustained improvement in QoL was seen in LG according to the QoL-AGHDA questionnaire.

CONCLUSION

In this pilot study, a fixed very low GH dose improved QoL in GHD adults without any induction of fluid retention. Other effects were comparable to those produced by the standard GH dose. Replacement with a very low GH dose could therefore be a treatment option in hypopituitary patients, especially in patients who do not tolerate higher GH dosage. Trial registration This study is registered at ClinicalTrials.gov, EU-nr 2009-016783-37.

Long-term Safety of Growth Hormone in Adults With Growth Hormone Deficiency: Overview of 15 809 GH-Treated Patients

CONTEXT

Data on long-term safety of growth hormone (GH) replacement in adults with GH deficiency (GHD) are needed.

OBJECTIVE

We aimed to evaluate the safety of GH in the full KIMS (Pfizer International Metabolic Database) cohort.

METHODS

The worldwide, observational KIMS study included adults and adolescents with confirmed GHD. Patients were treated with GH (Genotropin [somatropin]; Pfizer, NY) and followed through routine clinical practice. Adverse events (AEs) and clinical characteristics (eg, lipid profile, glucose) were collected.

RESULTS

A cohort of 15 809 GH-treated patients were analyzed (mean follow-up of 5.3 years). AEs were reported in 51.2% of patients (treatment-related in 18.8%). Crude AE rate was higher in patients who were older, had GHD due to pituitary/hypothalamic tumors, or adult-onset GHD. AE rate analysis adjusted for age, gender, etiology, and follow-up time showed no correlation with GH dose. A total of 606 deaths (3.8%) were reported (146 by neoplasms, 71 by cardiac/vascular disorders, 48 by cerebrovascular disorders). Overall, de novo cancer incidence was comparable to that in the general population (standard incidence ratio 0.92; 95% CI, 0.83-1.01). De novo cancer risk was significantly lower in patients with idiopathic/congenital GHD (0.64; 0.43-0.91), but similar in those with pituitary/hypothalamic tumors or other etiologies versus the general population. Neither adult-onset nor childhood-onset GHD was associated with increased de novo cancer risks. Neutral effects were observed in lipids/fasting blood glucose levels.

CONCLUSION

These final KIMS cohort data support the safety of long-term GH replacement in adults with GHD as prescribed in routine clinical practice.

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

DESIGN

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

PATIENTS

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

MEASUREMENTS

AEs including hypotension, hypoglycaemia and nausea/vomiting.

RESULTS

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

CONCLUSIONS

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

Clinical, Diagnostic, and Therapeutic Aspects of Growth Hormone Deficiency During the Transition Period: Review of the Literature

The role of growth hormone (GH) during childhood and adulthood is well established. Once final stature is reached, GH continues to act during the transition, the period between adolescence and adulthood in which most somatic and psychological development is obtained. The achievement of peak bone mass represents the most relevant aspect of GH action during the transition period; however, equally clear is its influence on body composition and metabolic profile and, probably, in the achievement of a complete gonadal and sexual maturation. Despite this, there are still some aspects that often make clinical practice difficult and uncertain, in particular in evaluating a possible persistence of GH deficiency once final stature has been reached. It is also essential to identify which subjects should undergo re-testing and, possibly, replacement therapy, and the definition of unambiguous criteria for therapeutic success. Moreover, even during the transition phase, the relationship between GH substitution therapy and cancer survival is of considerable interest. In view of the above, the aim of this paper is to clarify these relevant issues through a detailed analysis of the literature, with particular attention to the clinical, diagnostic and therapeutic aspects.

Impact of Long-Term Growth Hormone Replacement Therapy on Metabolic and Cardiovascular Parameters in Adult Growth Hormone Deficiency: Comparison Between Adult and Elderly Patients

Growth hormone deficiency (GHD) in adults is due to a reduced growth hormone (GH) secretion by the anterior pituitary gland which leads to a well-known syndrome characterized by decreased cognitive function and quality of life (QoL), decreased bone mineral density (BMD), increased central adiposity with a reduction in lean body mass, decreased exercise tolerance, hyperlipidemia and increased predisposition to atherogenesis. Considering some similar features between aging and GHD, it was thought that the relative GH insufficiency of the elderly person could make an important contribution to the fragility of elderly. GH stimulation tests are able to differentiate GHD in elderly patients (EGHD) from the physiological reduction of GH secretion that occurs with aging. Although there is no evidence that rhGH replacement therapy increases the risk of developing Diabetes Mellitus (DM), reducing insulin sensitivity and inducing cardiac hypertrophy, long-term monitoring is, however, also mandatory in terms of glucose metabolism and cardiovascular measurements. In our experience comparing the impact of seven years of rhGH treatment on metabolic and cardiovascular parameters in GHD patients divided in two groups [adult (AGHD) and elderly (EGHD) GHD patients], effects on body composition are evident especially in AGHD, but not in EGHD patients. The improvements in lipid profile were sustained in all groups of patients, and they had a lower prevalence of dyslipidemia than the general population. The effects on glucose metabolism were conflicting, but approximately unchanged. The risk of DM type 2 is, however, probably increased in obese GHD adults with impaired glucose homeostasis at baseline, but the prevalence of DM in GHD is like that of the general population. The increases in glucose levels, BMI, and SBP in GHD negatively affected the prevalence of Metabolic Syndrome (MS) in the long term, especially in AGHD patients. Our results are in accordance to other long-term studies in which the effects on body composition and lipid profile are prominent.

Excess Mortality Among Hospitalized Patients With Hypopituitarism-A Population-Based, Matched-Cohort Study

CONTEXT

Patients with hypopituitarism face excess mortality in the long-term outpatient setting. However, associations of pituitary dysfunction with outcomes in acutely hospitalized patients are lacking.

OBJECTIVE

The objective of this work is to assess clinical outcomes of hospitalized patients with hypopituitarism with or without diabetes insipidus (DI).

DESIGN, SETTING, AND PATIENTS

In this population-based, matched-cohort study from 2012 to 2017, hospitalized adult patients with a history of hypopituitarism were 1:1 propensity score-matched with a general medical inpatient cohort.

MAIN OUTCOME MEASURES

The primary outcome was in-hospital mortality. Secondary outcomes included all-cause readmission rates within 30 days and 1 year, intensive care unit (ICU) admission rates, and length of hospital stay.

RESULTS

After matching, 6764 cases were included in the study. In total, 3382 patients had hypopituitarism and of those 807 (24%) suffered from DI. All-cause in-hospital mortality occurred in 198 (5.9%) of patients with hypopituitarism and in 164 (4.9%) of matched controls (odds ratio [OR] 1.32, [95% CI, 1.06-1.65], P = .013). Increased mortality was primarily observed in patients with DI (OR 3.69 [95% CI, 2.44-5.58], P < .001). Patients with hypopituitarism had higher ICU admissions (OR 1.50 [95% CI, 1.30-1.74], P < .001), and faced a 2.4-day prolonged length of hospitalization (95% CI, 1.94-2.95, P < .001) compared to matched controls. Risk of 30-day (OR 1.31 [95% CI, 1.13-1.51], P < .001) and 1-year readmission (OR 1.29 [95% CI, 1.17-1.42], P < .001) was higher among patients with hypopituitarism as compared with medical controls.

CONCLUSIONS

Patients with hypopituitarism are highly vulnerable once hospitalized for acute medical conditions with increased risk of mortality and adverse clinical outcomes. This was most pronounced among those with DI.

Safety of current recombinant human growth hormone treatments for adults with growth hormone deficiency and unmet needs

INTRODUCTION

Growth hormone (GH) deficiency (GHD) in adults is characterized by abnormal body composition, unfavorable cardiovascular risk factors, and poor quality of life. The diagnosis is made within appropriate clinical settings and according to established guidelines. Numerous studies have shown that GH treatment improves body composition, cardiovascular risk factors, physical capacity, and quality of life while issues on safety, in particular long-term safety, remain.

AREAS COVERED

Short- and long-term safety of GH replacement in adults with GHD.

EXPERT OPINION

Adults with GHD are an inhomogeneous group of patients and GH replacement requires individual considerations. Most adverse effects are mild and transient and related to fluid retention and GH dose. In patients without comorbidities long-term GH treatment is safe and development of diabetes, cardiovascular disease, or tumors are not increased. Furthermore, mortality is not increased. Patients with risk factors should be identified before GH treatment is initiated and an optimal balance between benefit and risk established. Studies with sufficient duration and power to identify the development of cardiovascular diseases and cancers are still awaited. Effective management of comorbidities can be expected to decrease morbidity and mortality and improve quality of life. Studies with long-acting GH formulations are ongoing and available data indicate similar effects and short-time safety.

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.

Targeted literature review of the humanistic and economic burden of adult growth hormone deficiency

BACKGROUND

Quality of life (QoL) and health economic data are becoming increasingly important factors in healthcare decision making. While there is a wealth of information establishing the benefit of growth hormone (GH) replacement therapy in adults with growth hormone deficiency (aGHD), recent reviews on the QoL and health economic impact of aGHD and the effect of treatment on these factors is limited.

OBJECTIVE

The aim of this article is to summarize the impact of early and sustained treatment on the QoL and economic burden of aGHD by conducting a targeted literature review.

METHODS

Standard electronic databases, including PubMed and the Cochrane collaboration website, were searched for publications between January 2006 and July 2016 for evidence of the humanistic and economic burden of aGHD. Search terms included growth hormone deficiency, health-related quality of life, HRQoL, patient-reported outcomes, outcome assessment, well-being and adherence.

RESULTS

The literature search identified 732 initial hits and a final 14 publications were included. The analysis showed that the economic burden of aGHD is largely driven by the productivity losses associated with the disease. This is because most patients with aGHD are of working age and the QoL domains (memory & concentration and energy & vitality) most commonly affected by aGHD severely impair a person's ability to work and may limit their contribution to society.

CONCLUSION

Untreated aGHD can seriously affect patients' functioning. Early and continued treatment with GH replacement therapy could potentially improve the QoL and reduce the economic burden associated with aGHD. This review has limitations: only English language articles published since January 2006 were included and many of the studies were conducted in the Nordic countries; it is unclear how representative these studies are of the population as a whole. This was a literature review and not a systematic review, as it was thought to be unlikely that, in this rare disease, any additional publications would have been identified. Overall, this review reveals a paucity of data in this underserved population and points to research gaps which could be addressed with new studies.

Short- and long-term responsiveness to low dose growth hormone (GH) in adult GH deficiency: Role of GH receptor polymorphism

In patients with growth hormone (GH) deficiency (GHD), low doses of recombinant human GH (rhGH) have a similar or better long-term clinical effect than higher doses. Pharmacogenetic studies suggest that GH receptor (GHR) polymorphism only influences some metabolic parameters. Nonetheless, there is no clear scientific evidence proving the effects of lower rhGH dose regimens on metabolic parameters. The aim of our prospective study was to evaluate the effects of GHR polymorphism in adult GHD patients treated with low rhGH dose during short- (6 and 12 months) and long-term (5 years) follow-up. Sixty-nine GHD adult patients were studied, before and during treatment with rhGH, using a standardised low-dose protocol calculated on the basis of body weight (0.01-0.03 mg kg^-1  week^-1 ) and monitored by an insulin-like growth factor (IGF)-I plasma assay, as well as anthropometric and metabolic parameters. The GHR genotype (flfl, fld3 or d3d3) was determined from the peripheral blood. d3-GHR carriers showed a more effective short- and long-term response to low rhGH dose with respect to low-density lipoprotein reduction, body composition and blood pressure (homozygous patients only); d3-GHR homozygosity is related to a significant IGF-I increase during short-term follow-up. Regression analysis demonstrated that rhGH dose, age at diagnosis and GHR genotype are the major determinants of IGF-I increase at 6 and 12 months of replacement therapy. The d3d3-GHR genotype may influence some metabolic effects during the short- and long-term follow-up of low rhGH dose and could be an independent determinant of the increase of IGF- I during short-term follow-up.

Comorbidities in patients with non-functioning pituitary adenoma: influence of long-term growth hormone replacement

BACKGROUND

Patients with hypopituitarism have an increased mortality. The aim of this study was to investigate comorbidities including cerebral infarction, type 2 diabetes mellitus (T2DM) and malignant tumors in patients with non-functioning pituitary adenomas (NFPA) with and without growth hormone replacement therapy (GHRT).

METHODS

Observational cohort study in patients with NFPA within the western region of Sweden. Subjects were identified through the National Patient Registry and followed between 1987 and 2014. Patient records were reviewed and standardized incidence ratios (SIRs) with 95% CIs for comorbidities were calculated.

RESULTS

In total, 426 patients were included, 206 with GHRT and 219 without. Median (range) follow-up time for patients with and without GHRT was 12.2 (0–24) and 8.2 (0–27) years, respectively. Mean ± s.d. BMI was 28.5 ± 4.5 and 26.5 ± 4.4 for patients with and without GHRT, respectively (P < 0.001). Incidence of cerebral infarction was increased (SIR: 1.39; 95% CI: 1.03–1.84; P = 0.032), with no difference between patients with and without GHRT. SIR for T2DM in patients not receiving GHRT was increased (1.65; 1.06–2.46; P = 0.018), whereas the incidence in patients receiving GHRT was not (0.99; 0.55–1.63; P = 0.99). The incidence of malignant tumors was not increased, either in patients with or without GHRT.

CONCLUSION

The incidence of cerebral infarction is increased in patients with NFPA irrespective of GHRT. Patients without GHRT had an increased risk of T2DM, whereas patients with GHRT had a normal incidence of T2DM, despite having higher BMI. Incidence of malignant tumors was not increased. Thus, long-term GHRT seems to be safe regarding risk of comorbidities.

Biomarkers of GH action in children and adults

Growth hormone (GH) and IGF-I levels in serum are used as biomarkers in the diagnosis and management of GH-related disorders but have not been subject to structured validation. Auxological parameters in children and changes in body composition in adults, as well as metabolic parameters and patient related outcomes are used as clinical and surrogate endpoints. New treatment options, such as long acting GH and GH antagonists, require reevaluation of the currently used biochemical biomarkers. This article will review biomarkers, surrogate endpoints and clinical endpoints related to GH treatment in children and adults as well as in acromegaly.

The prevalence of the metabolic syndrome and associated cardiovascular complications in adult-onset GHD during GH replacement: a KIMS analysis

BACKGROUND

Adult-onset growth hormone deficiency (AO-GHD) is associated with an increased prevalence of the metabolic syndrome (MetS).

AIM

To determine the effect of GH replacement on the prevalence of MetS in AO-GHD and to study the impact of MetS on the incidence of cardiovascular events during GH replacement.

PATIENTS AND METHODS

1449 AO-GHD patients (males 48.9%; mean age 48.9 ± 12.8 year) were retrieved from KIMS (Pfizer International Metabolic Database). The prevalence of MetS (using International Diabetes Federation criteria) and its components were calculated at baseline and after one year of GH replacement. The relative risk to develop cardiovascular events according to the presence of MetS at baseline was assessed in another group of 3282 patients after prolonged GH replacement.

RESULTS

The prevalence of MetS was 46.9% at baseline and 48.2% after one year of GH replacement (P = NS). The percentage of patients with abnormal waist circumference decreased significantly (80.3 vs 77.4%; P < 0.001), but impaired glucose metabolism (17.1 vs 23.3%; P < 0.001) increased and HDL cholesterol (48.2 vs 50.9%; P = 0.011) decreased. Switch from MetS to NoMS (18.5%) and from NoMS to MetS (18.8%) occurred. All patients showed a significant and comparable amelioration of quality of life. During seven years of GH replacement patients with MetS had a 66% higher risk (P = 0.0016) to develop a new coronary disease compared to NoMS.

CONCLUSION

MetS prevalence remains unchanged in AO-GHD during one year of GH replacement whereas its components are differentially affected. Besides GH replacement, consequent pharmacotherapy of all risk factors and endorsement of lifestyle intervention appears to be of uttermost importance together with early GHD diagnosis to prevent cardiovascular disease during prolonged treatment.

Decorin, a growth hormone-regulated protein in humans

CONTEXT

Growth hormone (GH) stimulates connective tissue and muscle growth, an effect that is potentiated by testosterone. Decorin, a myokine and a connective tissue protein, stimulates connective tissue accretion and muscle hypertrophy. Whether GH and testosterone regulate decorin in humans is not known.

OBJECTIVE

To determine whether decorin is stimulated by GH and testosterone.

DESIGN

Randomized, placebo-controlled, double-blind study.

PARTICIPANTS AND INTERVENTION

96 recreationally trained athletes (63 men, 33 women) received 8 weeks of treatment followed by a 6-week washout period. Men received placebo, GH (2 mg/day), testosterone (250 mg/week) or combination. Women received either placebo or GH (2 mg/day).

MAIN OUTCOME MEASURE

Serum decorin concentration.

RESULTS

GH treatment significantly increased mean serum decorin concentration by 12.7 ± 4.2%; P < 0.01. There was a gender difference in the decorin response to GH, with greater increase in men than in women (∆ 16.5 ± 5.3%; P < 0.05 compared to ∆ 9.4 ± 6.5%; P = 0.16). Testosterone did not significantly change serum decorin. Combined GH and testosterone treatment increased mean decorin concentration by 19.5 ± 3.7% (P < 0.05), a change not significantly different from GH alone.

CONCLUSION

GH significantly increases circulating decorin, an effect greater in men than in women. Decorin is not affected by testosterone. We conclude that GH positively regulates decorin in humans in a gender-dimorphic manner.

Growth hormone deficiency and hypopituitarism in adults after complicated mild traumatic brain injury

PURPOSE

Traumatic brain injury is considered the main cause of hypopituitarism in adults, and GH deficiency appears to be the most frequent pituitary deficit. Most of the available studies have included all degrees of severity of trauma. We aimed to assess pituitary function and GH deficiency in adult patients at different time lengths after complicated mild TBI according to Glasgow Coma Scale. We also aimed to evaluate whether mild TBI patients with GH deficiency had developed alterations in the glycolipid profile.

METHODS

Forty-eight patients (34 men and 14 women) with complicated mild TBI were included in the study. Twenty-three patients were evaluated at 1 year (Group A) and 25 patients at 5 years or longer after the injury (Group B). All patients underwent basal hormonal evaluation for pituitary function. GH deficiency was investigated by the combined test (GH releasing hormone + arginine). The glycolipid profile was also evaluated.

RESULTS

GH deficiency occurred in 8/23 patients (34.7 %) of Group A and in 12/25 patients (48 %) of Group B. In addition, two patients, one in each group, showed evidence of central hypothyroidism. Patients with GH deficiency, especially in Group A, presented a higher frequency of visceral adiposity and adverse metabolic profile as compared to no-GH deficiency patients.

CONCLUSIONS

Patients examined at 1 year or several years from complicated mild TBI had a similarly high occurrence of isolated GH deficiency, which was associated with visceral adiposity and metabolic alterations. Our findings suggest that patients undergone complicated mild TBI should be evaluated for GH deficiency even after several years from trauma.

Safety and effectiveness of long-term growth hormone therapy in Japanese patients with adult growth hormone deficiency: a postmarketing, multicenter, observational study

We aimed to evaluate the long-term safety and effectiveness of growth hormone (GH) therapy in Japanese patients with adult growth hormone deficiency (AGHD). In this observational, multicenter study, Norditropin^® (Novo Nordisk A/S, Bagsvaerd, Denmark) was administered as injections of 0.021 mg/kg/week as a starting dose divided into 6-7 doses/week. The dose was increased according to clinical response. Patients' data were obtained from medical records. Measurements (lipids, glucose metabolism, and body composition) taken at baseline; 3, 6, and 12 months; and yearly until the end of the study were collected. Adverse drug reactions (ADRs), serious ADRs, and serious adverse events (SAEs) were evaluated. Of 387 registered patients, 334 were eligible for safety. After GH treatment initiation, a marked decrease in total cholesterol was observed earlier in the child-onset group than in the adult-onset group. LDL-cholesterol also decreased, but no significant differences in changes in LDL-cholesterol between adult-onset and child-onset groups were found. A significant increase in HDL-cholesterol starting 1 year after GH treatment initiation was found in the adult-onset group. There was no effect of GH treatment on glucose metabolism. Because of the small number of dual-energy X-ray absorptiometry data, the overall assessment of changes of body composition was difficult. Fifty-six (16.8%), 12 (3.6%), and 35 (10.5%) patients experienced ADRs, serious ADRs, and SAEs, respectively. This study demonstrated a favorable long-term safety and effectiveness profile of GH therapy in AGHD patients in the real-life Japanese clinical practice setting.

Cardiovascular alterations in adult GH deficiency

There is a growing body of evidence indicating that patients with adult GH deficiency (GHD) are characterized by a cluster of traditional and emerging cardiovascular risk factors and markers, which can significantly increase their cardiovascular morbidity and mortality possibly linked to aberrations in GH status. Patients with adult GHD present multiple different cardiovascular abnormalities. In addition, cardiovascular risk in adult GHD is increased due to altered body composition, abnormal lipid profile, insulin resistance and impaired glucose metabolism. Cardiovascular risk factors can be reversed, at least partially, after GH replacement. However, evidence on the effects of GH replacement on cardiovascular events and mortality is too limited in adult GHD patients. Aim of this review is to provide an at-a-glance overview of the role of the GH/IGF-I on the cardiovascular system and the state of art of the effects of GH replacement on cardiovascular system.

Life expectancy in patients with pituitary adenoma receiving growth hormone replacement

OBJECTIVE

Hypopituitarism has been associated with increased mortality. The excess mortality may be due to untreated growth hormone (GH) deficiency but also due to various underlying disorders. We therefore analysed mortality in patients with only one underlying disorder, non-functioning pituitary adenoma (NFPA), with and without GH replacement therapy (GHRT).

DESIGN AND METHOD

Patients with NFPA in the western region of Sweden, 1997-2011, were identified through the National Patient Registry and cross-referenced with several National Health Registries. All patient records were reviewed. Standardised mortality ratios (SMRs) with 95% confidence intervals (CIs) were calculated using the general population as reference. Cox-regression models were performed to identify predictors of mortality.

RESULTS

A total of 426 NFPA patients with 4599 patient-years were included, of whom 207 had used GHRT and 219 had not received GHRT. Median (range) follow-up in patients with and without GHRT was 12.2 (0-25) and 8.2 (0-27) years, respectively. Other pituitary hormone deficiencies were more frequent in the GHRT group than those in the non-GHRT group. SMR was 0.65 (95% CI, 0.44-0.94; P = 0.018) for the GHRT group and 1.16 (0.94-1.42; P = 0.17) for the non-GHRT group. Direct comparison between the groups showed reduced mortality among those who were GH replaced (P = 0.0063). The SMR for malignant tumours was reduced in the GHRT-group (0.29; 0.08-0.73; P = 0.004) but not in untreated patients.

CONCLUSIONS

Selection bias explaining some of the results cannot be excluded. However, NFPA patients with GHRT had reduced overall mortality compared with the general population, and death due to malignancy was not increased. This suggests that long-term GHRT is safe in adult patients selected for treatment.

Seven years of follow up of trabecular bone score, bone mineral density, body composition and quality of life in adults with growth hormone deficiency treated with rhGH replacement in a single center

BACKGROUND

Adult growth hormone deficiency (AGHD) is characterized by impaired physical activity, diminished quality of life (QoL), weight and fat mass gain, decreased muscle mass and decreased bone mineral density (BMD). The aim of this study was to evaluate the effects of long-term treatment (7 years) with recombinant human growth hormone (rhGH) on metabolic parameters, body composition (BC), BMD, bone microarchitecture and QoL.

PATIENTS AND METHODS

In this prospective study, BMD and BC were assessed by dual-energy X-ray absorptiometry (DXA). Bone microarchitecture was assessed with the trabecular bone score (TBS). The QoL-AGHDA test was used to assess QoL.

RESULTS

A total of 18 AGHD patients (mean age, 37.39 ± 12.42) were included. Body weight and body mass index (BMI) showed a significant increase after 7 years (p = 0.03 and p = 0.001, respectively). There was a significant tendency of body fat mass (BFM) (p = 0.028) and lean body mass (LBM) (p = 0.005) to increase during the 7 years of rhGH treatment. There was a significant increase in lumbar spine (LS) BMD (p = 0.01). TBS showed a nonsignificant decrease after 7 years of treatment, with a change of -0.86% ± 1.95. QoL showed a large and significant improvement (p = 0.02).

CONCLUSION

Long-term rhGH treatment in AGHD patients induces a large and sustained improvement in QoL. Metabolic effects are variable with an increase in LBM as well as in BMI and BFM. There is a positive effect on BMD based on the increase in LS BMD, which stabilizes during long-term therapy and is not associated with a similar increase in bone microarchitecture.

Pituitary-Adrenal Axis in Prader Willi Syndrome

PURPOSE

Prader Willi syndrome (PWS) is a rare genetic condition that has concurrent endocrinological insufficiencies. The presence of growth hormone deficiency has been well documented, but adrenal insufficiency (AI) is not widely reported. A review was conducted to investigate its prevalence and relevance in PWS in both adults and children.

METHODOLOGY

A literature review was performed with the search terms "Prader-Willi syndrome" and "adrenal insufficiency".

RESULTS

The review found studies disagree on the prevalence and method of investigation of AI in PWS. Case studies demonstrate that patients with PWS are at risk of premature death, often secondary to respiratory infections. The possibility that this may be the result of the inability to mount an effective cortisol response has been studied, with some evidence confirming AI in PWS patients. Most reports agreed AI is present in PWS, however, Farholt et al. showed no HPA axis dysfunction in adults, suggesting that perhaps it is rare in adults, and children should be the focus of further studies.

CONCLUSION

AI is present in some patients with PWS. Further research is required to ensure optimal treatment can be implemented and to prevent premature deaths related to adrenal insufficiency. Clinicians should have a low threshold for testing the adrenal axis and considering treatment for adrenal insufficiency in PWS patients.

Characteristics and outcomes of Italian patients from the observational, multicentre, hypopituitary control and complications study (HypoCCS) according to tertiles of growth hormone peak concentration following stimulation testing at study entry

OBJECTIVE

To determine whether characteristics and outcomes of Italian patients in the observational global Hypopituitary Control and Complication Study (HypoCCS) differed according to the degree of GH deficiency (GHD).

DESIGN

Patients were grouped by tertiles of stimulated GH peak concentration at baseline (Group A lowest tertile, n = 342; Group B middle tertile, n = 345; Group C highest tertile, n = 338).

RESULTS

Baseline demographics, lipid levels, body mass index categories and mean Framingham cardiovascular risk indexes were similar in the three groups and remained substantially unchanged over time, with no subsequent significant between-group differences (except mean levels of triglycerides increased in the highest tertile group). GHD was adult-onset for >75% of patients in all groups. The percentage of patients with multiple pituitary deficiencies was higher in Group A than in the other groups; isolated GHD was reported with highest frequency in Group C. Patients in Group A received the lowest mean starting dose of GH. Hyperlipidaemia at baseline was reported in 35·1%, 31·1% and 24·7% of patients in groups A, B and C, respectively (P = 0·029). Mean duration of GH treatment was 7·21, 5·45 and 4·96 years, respectively. The proportion of patients with adverse events did not differ significantly between groups, with a low prevalence over time of diabetes and cancer.

CONCLUSIONS

In Italian patients from HypoCCS, the level of GH deficit did not influence changes over time in metabolic parameters or adverse event profile, despite differences in GHD severity at baseline and in the starting GH dose.

Reviewing the safety of GH replacement therapy in adults

CONTEXT

Systematic data on safety of growth hormone (GH) replacement therapy in adult GH deficiency is lacking.

OBJECTIVE

To systematically describe safety of adult GH replacement therapy on glucose metabolism and long term safety.

DESIGN

A systematic web-based search of PubMed was performed guided by the Standard Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

OUTCOME

Randomised controlled trials of ≥3 months and open trials for ≥12 months with more than 50 adult patients (50 patient years, prospective and retrospective) including adverse event reporting as well as articles on mortality primarily on adult onset patients, reporting mortality ratios on GH treated patients, were included for the review.

RESULTS

Based on the defined selection criteria 94 studies were included. The short-term early placebo controlled trials did not demonstrate an increased frequency of diabetes mellitus (DM) and the long-term open studies did not consistently show an increased incidence of DM during GH replacement. The concern that long-term GH replacement might increase the risk of primary cancer, secondary neoplasia after tumour treatment and recurrence of previous tumours was not evident in the study data.

CONCLUSION

Based on available data, short- and long-term adult GH replacement in patients with severe GH deficiency and hypopituitarism is safe. However, the small number of subjects, limitation of long-term of GH treatment data and absence of an adequate control population is still a limitation for the interpretation of these data.

Evolution of glycated haemoglobin in adults on growth hormone replacement therapy

OBJECTIVES

To evaluate the effects of GH replacement therapy (GHR) for 3 years on glycated haemoglobin (HbA1c) and on the presence of dysglycaemia at any time during follow-up in Spanish adult patients with growth hormone deficiency (GHD).

STUDY DESIGN

A retrospective study of 41 patients with GHD was conducted using baseline and long-term data. Changes in HbA1c values during the first 3 years of GHR were studied in both the overall population and patients with or without dysglycaemia during follow-up. Dysglycaemia was defined as FPG ≥ 100 mg/dl and/or HbA1c ≥ 5.7%.

RESULTS

Mean HbA1c value (5.4 ± 0.4% at baseline) increased during the first and second years of GHR (HbA1c 5.5 ± 0.4%, p=0.05, and 5.5 ± 0.4%, p=0.006 respectively). This increase was not maintained during the third year (HbA1c 5.4 ± 0.3%, p=0.107) of GHR. Twenty-eight patients (68.2%) had dysglycaemia during follow-up, 9 of them since baseline. In the 19 patients without baseline dysglycaemia, HbA1c increased during the first year and remained stable in the next 2 years (mean HbA1c 5.2 ± 0.4% at baseline; 5.5 ± 0.4% at 1 year, p<0.050; 5.4 ± 0.4% at 2 years, p=0.004, and 5.4 ± 0.4% at 3 years, p=0.016). In the 9 patients with baseline dysglycaemia, HbA1c did not significantly change during the 3 years of GHR therapy.

CONCLUSIONS

HbA1c values increased during the first 2 years of GHR therapy. In patients with no dysglycaemia before treatment, HbA1c steadily increased over the 3 years. However, it did not change in patients with baseline dysglycaemia.

Hypopituitarism: growth hormone and corticotropin deficiency

This article presents an overview of adult growth hormone deficiency (AGHD) and corticotropin deficiency (central adrenal failure, CAI). Both conditions can result from various ailments affecting the hypothalamus or pituitary gland (most frequently a tumor in the area or its treatment). Clinical manifestations are subtle in AGHD but potentially life-threatening in CAI. The diagnosis needs dynamic testing in most cases. Treatment of AGHD is recommended in patients with documented severe deficiency, and treatment of CAI is mandatory in all cases. Despite significant progress in replacement hormonal therapy, more physiologic treatments and more reliable indicators of treatment adequacy are still needed.

Growth hormone replacement in adults - current standards and new perspectives

Growth hormone deficiency (GHD) in adults is an established clinical syndrome characterised by adverse body composition with more body fat than lean body mass, unfavourable blood lipids, decreased physical fitness and poor quality of life. No specific biomarker for GHD exists and the sometimes difficult diagnosis should be made in accordance with, established guidelines. Measurements of insulin-like growth factor I (IGF-I) is often not sufficient for the diagnosis and stimulation tests of the GH reserve are required. After diagnosis of GHD, treatment with GH should be initiated with a low dose, and gradually increased aiming at obtaining an IGF-I level within the upper part of the normal range for age matched healthy controls. Most side effects are mild and transient and attenuated by gradual dose increments. Numerous studies have shown that GH treatment can improve body composition, cardiovascular risk factors, physical capacity and quality of life. However, studies on effects beyond 5 years are few and despite encouraging preliminary reports the ultimate endpoint demonstrating that GH treatment has beneficial effects on mortality, cardiovascular events and fractures without an increase in cancer incidence remain to be solidly demonstrated and studies to resolve these issues are awaited. Trials with long acting GH formulations are ongoing and available data indicate similar effects on outcome measures compared to the effects of daily injections. This review will give an overview of clinically relevant issues of GHD including advice for management of these patients.

Effect of long-term GH replacement therapy on cardiovascular outcomes in GH-deficient patients previously treated for acromegaly: a sub-analysis from the Dutch National Registry of Growth Hormone Treatment in Adults

OBJECTIVE

The effect of GH deficiency (GHD) on the metabolic profile of acromegaly patients is unclear in patients previously treated for acromegaly, as are the efficacy and safety of GH treatment in this particular group. The aim of the study is to describe the characteristics of patients with severe GHD who were previously treated for acromegaly, and to investigate the effects of long-term GH treatment on cardiovascular risk factors and morbidity, compared with patients who were treated for a nonfunctioning pituitary adenoma (NFPA).

DESIGN

A nationwide surveillance study.

METHODS

Sixty-five patients from the Dutch National Registry of Growth Hormone Treatment in Adults with previous acromegaly were compared with 778 patients with previous NFPA. Cardiovascular indices, including body composition, lipid profile, glucose metabolism, blood pressure, and morbidity were investigated.

RESULTS

GHD patients with previous acromegaly had an unfavorable metabolic profile comparable with or more than GHD patients with previous NFPA. GH treatment led to improvement of the lipid profile in both groups, also after excluding patients using lipid-lowering medication. In patients with previous acromegaly, HbA1c levels increased more than in patients with previous NFPA (estimate 0.03, 95% CI 0.002-0.06, P=0.04). The risk for developing cardiovascular diseases was not different between the groups.

CONCLUSIONS

The patients with GHD after previous acromegaly have an unfavorable metabolic profile comparable with patients with GHD after previous NFPA. In both groups, the lipid profile improves during GH treatment. Changes in glucose metabolism should be monitored closely. GH treatment in patients with GHD previously treated for acromegaly had no deleterious effect on cardiovascular morbidity.

Insulin-Like Growth Factor-I, Insulin-Like Growth factor Binding Protein-3 and Blood Hemoglobin Concentration in an Elderly Population

BACKGROUND

Insulin-like growth factor-I (IGF-I) serum level decreases with age, and this decrease may underlie hemoglobin (Hb) decrease. The objective of the study was to assess the relationship between IGF-I and insulin-like growth factor binding protein-3 (IGFBP-3) serum levels and Hb, after adjustment especially for major nutritional factors in an elderly population because IGF-I system depends on nutritional state, often impaired in the elderly.

METHODS

Hemoglobin concentration was tested for 672 participants evaluated during an outpatient geriatric assessment. IGF-I and IGFBP-3 serum levels were assessed by Enzyme Linked Immunosorbent Assay. The molar ratio of IGF-I/IGFBP-3 that reflects the bioavailable IGF-I was calculated. Levels of IGF-I and IGFBP-3 were plotted against quartiles of Hb. Final linear models for IGF-I, IGFBP-3 and ratio molar included factors that could modify the Hb level.

RESULTS

Mean age (SD) of the sample was 78.0 (8.5) years old and 32% were men. After adjustment for age and sex, IGF-I serum level, IGFBP-3 serum level and molar ratio significantly increased with increasing quartiles of Hb. After adjustment for age, gender, diabetes, albumin, pre-albumin, renal function, total cholesterol, angiotensin converting enzyme inhibitors and angiotensin II receptor blockers consumption, C-Reactive Protein, Hb was significantly associated and with IGF-I level (p = .002) and molar ratio (p = .02).

CONCLUSIONS

IGF-I serum level and IGF-I/IGFBP-3 molar ratio were associated with Hb in an elderly population, independently of nutritional biological parameters. Thus, the association between the IGF-I system and Hb merits further investigation to determine whether interventions that modulate circulating IGF-I or IGF-I/BP3 ratio might preserve Hb in the elderly.

Effect of long-term GH replacement therapy on cardiovascular outcomes in isolated GH deficiency compared with multiple pituitary hormone deficiencies: a sub-analysis from the Dutch National Registry of Growth Hormone Treatment in Adults

OBJECTIVE

Isolated GH deficiency (IGHD) could provide a model to investigate the influence of GH deficiency per se and the effect of GH replacement therapy without the influence from other pituitary hormone deficiencies or their treatment. The aim of this study is to address the questions about differences between IGHD and multiple pituitary hormone deficiencies (MPHDs) in clinical presentation and in responsiveness to GH treatment.

DESIGN

A nationwide surveillance study was carried out to describe the difference in the clinical presentation and responsiveness to GH treatment of patients with IGHD and MPHDs.

METHODS

The Dutch National Registry of GH Treatment in Adults was founded in 1998 to gain more insight into long-term efficacy and safety of GH therapy. Out of 2891 enrolled patients, 266 patients with IGHD at the start of GH treatment were identified and compared with 310 patients with MPHDs. Cardiovascular indices will be investigated at baseline and during long-term follow-up, including body composition, lipid profile, glucose metabolism, blood pressure, and morbidity.

RESULTS

Patients with IGHD and MPHDs were demonstrated to be different entities at clinical presentation. Metabolically, patients with MPHDs had a larger waist circumference, lower HDL cholesterol level, and higher triglyceride level. The effect of GH treatment was comparable between patient groups. GH seems to protect against rising lipid levels and blood pressure, even after excluding patients using corresponding concomitant medication. The risk for cardiovascular disease or diabetes mellitus during follow-up was not different between patients with IGHD and MPHDs.

CONCLUSIONS

Patients with IGHD had a less impaired metabolic profile than patients with MPHDs at baseline. Influence of other pituitary hormone replacement therapies on the effect of GH treatment is not demonstrated.

Cross-sectional and longitudinal relation of IGF1 and IGF-binding protein 3 with lipid metabolism

BACKGROUND

Previous intervention studies in patients with GH disorders suggested an impact of IGF1 and IGF-binding protein 3 (IGFBP3) on lipid metabolism, whereas population-based studies revealed conflicting results. Therefore, we aimed to assess the cross-sectional and longitudinal associations between IGF1 or IGFBP3 serum levels and lipids (total, LDL, or HDL cholesterol and triglycerides) in a large-scale study.

METHODS

Data of 2935 subjects (1356 women) from the population-based Study of Health in Pomerania (SHIP) were used. ANOVA, quantile regression, and logistic regression models adjusted for age, waist circumference, physical activity, and alcohol consumption were performed.

RESULTS

In cross-sectional analyses, we detected that IGF1 and IGFBP3 levels were positively related to total and LDL cholesterol and inversely related to HDL cholesterol in both sexes. Furthermore, IGFBP3 levels showed a positive relationship to triglycerides. In total, IGFBP3 levels were more strongly associated to lipids than IGF1. In longitudinal analysis, we found no influence of baseline IGF1 or IGFBP3 serum concentration on incidentally elevated or reduced lipid levels. However, the positive relationship between IGFBP3 and incidentally elevated triglycerides barely missed statistical significance in women.

CONCLUSION

The present study showed strong cross-sectional associations between IGF1 or IGFBP3 and lipids, whereas no longitudinal relationships were revealed. Therefore, our findings suggest IGF1 and IGFBP3 as a risk marker rather than a risk factor for alterations in lipid metabolism. Further studies are needed to elucidate the mechanisms underlying the association between the GH/IGF axis and lipid metabolism.

Abnormal metabolic phenotype in middle-aged GH-deficient adults despite long-term recombinant human GH replacement

BACKGROUND

Adult GH deficiency (GHD) is associated with increased cardiovascular mortality. Recombinant human GH (rhGH) replacement has beneficial short-term metabolic effects. Although these positive effects sustain during longer follow-up, the prevalence of the metabolic syndrome (MS) remains increased in comparison with population data not adjusted for the higher mean BMI in GHD adults.

OBJECTIVE

To explore whether middle-aged patients with proposed physiological rhGH replacement have been normalized with respect to MS and its individual components in comparison with the general population, adjusted for age, sex, and BMI.

METHODS

One hundred and sixty-one GHD patients (aged 40-70 years) were studied before the start and after 5 years of rhGH replacement, and were compared with 1671 subjects (aged 45-66 years) from the general population (NEO Study).

RESULTS

MS PROPORTION IN GHD PATIENTS WAS 41.0% BEFORE THE START OF RHGH SUPPLETION, INCREASING TO 53.4% AFTER 5 YEARS (P=0.007). DESPITE CHRONIC RHGH REPLACEMENT, GHD PATIENTS HAD A 1.3-TIMES HIGHER MS PROPORTION THAN THE GENERAL POPULATION, INDEPENDENTLY OF AGE, SEX, AND BMI (95% CI 1.11.5, P=0.008). THE GHD POPULATION SHOWED A DIFFERENT METABOLIC PROFILE THAN THE GENERAL POPULATION WITH SIMILAR BMI: an increased risk of hypertriglyceridemia (adjusted prevalence ratio (PR) 2.0, 95% CI 1.7-2.3) and low HDL-C (adjusted PR 1.8, 95% CI 1.5-2.2), but less hyperglycemia (adjusted PR 0.5, 95% CI 0.4-0.7).

CONCLUSIONS

Despite 5 years of rhGH replacement, GHD patients still have a different metabolic profile and more frequently MS than the general population. These differences were independent of BMI, and resemble the unfavorable metabolic profile of untreated GHD patients, pointing to question the long-term benefits of rhGH replacement.

Baseline characteristics and effects of ten years of growth hormone (GH) replacement therapy in adults previously treated with pituitary irradiation

CONTEXT

Little is known of the importance of previous irradiation therapy for baseline characteristics and responsiveness to GH replacement in GH deficient (GHD) adults.

OBJECTIVE/DESIGN/PATIENTS

In this prospective, single-centre, open-label study, the effects of 10-year GH replacement were determined in 18 GHD adults that had previously received conventional external fractionated pituitary irradiation therapy (IRR group) and 18 non-irradiated GHD patients (non-IRR group). All patients had adult onset disease and complete deficiency of anterior pituitary hormones and both groups were comparable in terms of age, gender, body mass index (BMI), and waist:hip ratio.

RESULTS

At baseline, IRR patients had higher serum triglyceride (TG) and insulin levels and lower high density lipoprotein (HDL)-cholesterol (HDL-C) level than non-IRR patients (all p<0.05). The 10-year GH replacement improved body composition, bone mass and serum lipid profile without any between-group differences, except for a marginally more beneficial response in serum TG level in the IRR patients. After 10 years, there was no between-group difference in any variable after correction for a higher replacement dose of glucocorticoids in the IRR patients at study end using an analysis of covariance. During the 10-year GH replacement, 5 IRR patients suffered from vascular events (2 fatal) whereas only one non-fatal vascular event occurred in the non-IRR patients.

CONCLUSIONS

IRR patients with GHD display a more severely impaired cardiovascular risk profile at baseline, which was reversed by the 10-year GH replacement after correction for the higher glucocorticoid dose at study end. However, vascular events occurred more frequently in the IRR patients.

Extensive expertise in endocrinology: UK stance on adult GH replacement: the economist vs the endocrinologist

In the UK, through the use of a forced economic model, endocrinologists are in the curious position of offering GH replacement to some patients with severe GH deficiency (GHD) but withholding it from other patients with even more severe GHD. This approach is counter-intuitive to endocrine practice in treating endocrine deficiency states. For all other endocrine deficiencies, one would opt for treating those with the most severe biochemical evidence of deficiency first. If this endocrine approach was applied to adult GH replacement in an era of rationing, one would start with the GHD patients with a pathologically low IGF1 level. Given that the prevalence of subnormal IGF1 levels in a GHD population is age-dependent, this would result in GH replacement being offered to more young adult onset (AO) GHD and childhood onset GHD adults, and less often to middle-aged and elderly AO GHD adults. This in itself has the added advantage that the skeletal benefits appear more real in the former cohort of patients.

Influence of growth hormone on circulating fibroblast growth factor 21 levels in humans

OBJECTIVE

Findings from animal studies indicate that growth hormone (GH) may stimulate the production of the putative metabolic regulator fibroblast growth factor 21 (FGF21). We investigated whether circulating FGF21 levels are altered in patients with GH deficiency and characterized how levels of this growth factor are influenced by acute and long-term administration of GH, and the potential relationship between FGF21 and nonesterified fatty acids (NEFAs).

DESIGN AND SETTING

GH-deficient patients (n = 9) were studied prior to and during 1 year of replacement with GH. Healthy subjects (n = 8) received an intravenous bolus of GH with or without concomitant oral glucose. Healthy subjects and patients with heterozygous familial hypercholesterolaemia (n = 23) were monitored following increasing doses of GH for 3 weeks. The main outcome measures were serum FGF21 and NEFA levels. Studies were performed at two academic centres.

RESULTS

GH-deficient patients had FGF21 levels within the normal range, and GH replacement did not influence circulating FGF21 or NEFA concentrations. Acute GH administration to healthy control subjects did not change FGF21 levels, whereas an oral glucose load increased serum FGF21 by 25% and reduced NEFA levels by 48%. Similar effects were seen on administration of glucose together with GH. However, FGF21 levels increased dose dependently up to 3.7-fold in control subjects treated with GH for 3 weeks; simultaneously NEFA levels were increased by 47%.

CONCLUSIONS

GH is not critical for the maintenance of basal serum FGF21 levels in humans, but circulating FGF21 levels increase following administration of GH to healthy individuals. There is no correlation between plasma NEFA and circulating FGF21 levels.

Long-term effects of recombinant human GH replacement in adults with GH deficiency: a systematic review

BACKGROUND

The beneficial effects of recombinant human GH (rhGH) therapy in GH deficient (GHD) adults are well-established in the short term. However, data documenting the effects during prolonged follow-up are relatively scarce.

OBJECTIVE

To evaluate the reported effects of rhGH replacement (≥5 years) in GHD adults on biochemical and anthropometric parameters, quality of life (QoL), bone metabolism, muscle strength, serious adverse events and mortality.

METHODS

We conducted a systematic literature search. Quality assessment of retrieved papers was performed using a quality assessment based on the modified STROBE statement.

RESULTS

We included 23 prospective studies with a rhGH treatment duration ranging from 5 to 15 years. Overall, beneficial effects were reported on QoL, body composition, lipid profile, carotid intima media thickness and bone mineral density. In contrast, the prevalence of the metabolic syndrome, glucose levels, BMI and muscle strength were not, or negatively, influenced. Most of the studies were uncontrolled, lacked the presence of a control group (of non-treated GHD patients), and reported no data on lipid-lowering and anti-diabetic medication. Overall mortality was not increased.

CONCLUSION

rhGH treatment in adult GHD patients is well-tolerated and positively affects QoL in the long term. However, the metabolic and cardiovascular effects during long-term treatment are variable. The low numbers of long-term studies and studied patients and lack of control data hamper definite statements on the efficacy of prolonged treatment. Therefore continuous monitoring of the effects of rhGH replacement to enable an adequate risk-benefit analysis that may justify prolonged, potentially life-long, treatment is advisable.

Diagnosis and treatment of growth hormone deficiency in adults

The availability of synthetic recombinant human growth hormone (GH) in potentially unlimited quantities since the 1980s has improved understanding of the many nonstatural effects of GH on metabolism, body composition, physical and psychological function, as well as the consequences of GH deficiency in adult life. Adult GH deficiency is now recognized as a distinct if nonspecific syndrome with considerable adverse health consequences. GH replacement therapy in lower doses than those used in children can reverse many of these abnormalities and restore functional capacities toward or even to normal; if dosed appropriately, GH therapy has few adverse effects. Although some doubts remain about possible long-term risks of childhood GH therapy, most registries of adult GH replacement therapy, albeit limited in study size and duration, have not shown an increased incidence of cancers or of cardiovascular morbidity or mortality.

Fifteen years of GH replacement improves body composition and cardiovascular risk factors

OBJECTIVE

Few studies have determined the effects of more than 5-10 years of GH replacement in adults on body composition and cardiovascular risk factors.

DESIGN/PATIENTS

In this prospective, single-center, open-label study, the effects of 15 years of GH replacement on body composition and cardiovascular risk factors were determined in 156 hypopituitary adults (93 men) with adult-onset GH deficiency (GHD). Mean age was 50.5 (range 22-74) years at study start. Body composition was measured using dual-energy X-ray absorptiometry.

RESULTS

The mean initial GH dose of 0.55 (S.E.M. 0.03) mg/day was gradually lowered to 0.40 (0.01) mg/day after 15 years. The mean serum IGF1 SDS increased from -1.53 (0.10) at baseline to 0.74 (0.13) at study end (P<0.001 vs baseline). Lean soft tissue (LST) increased to 3% above the baseline level at study end (P<0.001). After a 9% decrease during the first year of treatment (P<0.001 vs baseline), body fat (BF) started to increase and had returned to the baseline level after 15 years. Serum levels of total cholesterol and LDL-cholesterol decreased and serum HDL-cholesterol level increased. Fasting plasma glucose increased from 4.4 (0.1) at baseline to 4.8 (0.1) mmol/l at study end (P<0.001). However, blood HbA1c decreased from 5.0 (0.1) to 4.6 (0.1) % (P<0.001).

CONCLUSIONS

Fifteen-year GH replacement in GHD adults induced a transient decrease in BF and sustained improvements of LST and serum lipid profile. Fasting plasma glucose increased whereas blood HbA1c was reduced.

Approach to testing growth hormone (GH) secretion in obese subjects

Identification of adults with GH deficiency (GHD) is challenging because clinical features of adult GHD are not distinctive and because clinical suspicion must be confirmed by biochemical tests. Adults are selected for testing for adult GHD if they have a high pretest probability of GHD, ie, if they have hypothalamic-pituitary disease, if they have received cranial irradiation or central nervous system tumor treatment, or if they survived traumatic brain injury or subarachnoid hemorrhage. Testing should only be carried out if a decision has already been made that if deficiency is found it will be treated. There are many pharmacological GH stimulation tests for the diagnosis of GHD; however, none fulfill the requirements for an ideal test having high discriminatory power; being reproducible, safe, convenient, and economical; and not being dependent on confounding factors such as age, gender, nutritional status, and in particular obesity. In obesity, GH secretion is reduced, GH clearance is enhanced, and stimulated GH secretion is reduced, causing a false-positive result. This functional hyposomatotropism in obesity is fully reversed by weight loss. In conclusion, GH stimulation tests should be avoided in obese subjects with very low pretest probability.

Hormones as doping in sports

Though we may still sing today, as did Pindar in his eighth Olympian Victory Ode, "… of no contest greater than Olympia, Mother of Games, gold-wreathed Olympia…", we must sadly admit that today, besides blatant over-commercialization, there is no more ominous threat to the Olympic games than doping. Drug-use methods are steadily becoming more sophisticated and ever harder to detect, increasingly demanding the use of complex analytical procedures of biotechnology and molecular medicine. Special emphasis is thus given to anabolic androgenic steroids, recombinant growth hormone and erythropoietin as well as to gene doping, the newly developed mode of hormones abuse which, for its detection, necessitates high-tech methodology but also multidisciplinary individual measures incorporating educational and psychological methods. In this Olympic year, the present review offers an update on the current technologically advanced endocrine methods of doping while outlining the latest procedures applied-including both the successes and pitfalls of proteomics and metabolomics-to detect doping while contributing to combating this scourge.

GH replacement causing acute hyperglycaemia and ketonuria in a type 1 diabetic patient

A state of insulin resistance is common to the clinical conditions of both chronic growth hormone (GH) deficiency and GH excess (acromegaly). GH has a physiological role in glucose metabolism in the acute settings of fast and exercise and is the only anabolic hormone secreted in the fasting state. We report the case of a patient in whom knowledge of this aspect of GH physiology was vital to her care. A woman with well-controlled type 1 diabetes mellitus who developed hypopituitarism following the birth of her first child required GH replacement therapy. Hours after the first dose, she developed a rapid metabolic deterioration and awoke with hyperglycaemia and ketonuria. She adjusted her insulin dose accordingly, but the pattern was repeated with each subsequent increase in her dose. Acute GH-induced lipolysis results in an abundance of free fatty acids (FFA); these directly inhibit glucose uptake into muscle, and this can lead to hyperglycaemia. This glucose–fatty acid cycle was first described by Randle et al. in 1963; it is a nutrient-mediated fine control that allows oxidative muscle to switch between glucose and fatty acids as fuel, depending on their availability. We describe the mechanism in detail.

Discontinuing long-term GH replacement therapy--a randomized, placebo-controlled crossover trial in adult GH deficiency

CONTEXT

Adult GH deficiency (GHD) is associated with impaired quality of life (QoL) and increased cardiovascular risk. Continued long-term efficacy in terms of QoL and cardiovascular risk factors has been indicated in open surveillance studies.

OBJECTIVES

The aim was to study the impact of discontinuation of long-term GH replacement on QoL, body composition, and metabolism.

DESIGN AND SETTING

We conducted a randomized, double-blind, placebo-controlled 4-month crossover trial in a referral center.

PATIENTS

Sixty adult hypopituitary patients with GHD and more than 3 yr of continuous GH replacement therapy (mean treatment duration, 10 yr) participated in the study.

INTERVENTION

Patients received GH or placebo.

MAIN OUTCOME MEASUREMENTS

We measured QoL using validated questionnaires; body composition using computer tomography, dual-energy x-ray absorptiometry, and bioelectrical impedance spectroscopy; and insulin sensitivity using the short insulin tolerance test.

RESULTS

Mean serum IGF-I decreased from 168 ± 52 to 98 ± 47 μg/liter during the placebo period (P < 0.001). Two QoL domains (emotional reactions and positive well-being) in the Nottingham Health Profile and Psychological General Well-Being questionnaires deteriorated during placebo, compared with GH treatment (P < 0.05). Waist circumference and sc and visceral fat mass increased, and extracellular water and muscle area decreased during the placebo period (all P < 0.05). C-reactive protein and total-, low-density lipoprotein-, and high-density lipoprotein-cholesterol increased, and insulin sensitivity improved during placebo, compared to GH treatment (P < 0.05).

CONCLUSION

After more than 3 yr of GH replacement therapy, a 4-month period of placebo treatment caused self-perceived deterioration in QoL and increased abdominal fat accumulation. Moreover, markers of systemic inflammation and lipid status deteriorated, whereas insulin sensitivity improved. Long-term continuous GH replacement is needed to maintain therapeutic effects of GH on QoL and cardiovascular risk factors.