GH Supplementation Effects on Cardiovascular Risk in GH Deficient Adult Patients: A Systematic Review and Meta-analysis

A 2024 Update on Growth Hormone Deficiency Syndrome in Adults: From Guidelines to Real Life

Background: Adult growth hormone deficiency (GHD) has been recognized since the late 1980s. The clinical manifestations of adult GHD are often nonspecific, and diagnosis relies on GH stimulation tests, which are intricate, costly, time-consuming, and may carry the risk of adverse effects. Diagnosis is further complicated by factors like age, sex, and BMI, which affect GH response during testing. Therefore, GH replacement therapy remains challenging, requiring careful individualized evaluation of risks and benefits. The aim of this review is to provide an update on diagnosing and treating adult GHD, addressing current limitations and challenges based on recent studies. Methods: We conducted a comprehensive review of the literature regarding the diagnosis and management of adult GHD by searching PubMed and EMBASE. Only articles in English were included, and searches were conducted up to August 2024. Results: A review of guidelines and literature up to 2024 highlights the significant heterogeneity in the data and reveals various protocols for managing GHD, covering both diagnostic and therapeutic approaches. Conclusions: Despite diagnostic and treatment advances, managing adult GHD remains challenging due to variable presentation and the need for personalized GH therapy. Future efforts should aim to improve and standardize diagnostic and treatment protocols.

Utilizing Somapacitan, a Long-acting Growth Hormone Formulation, for the Treatment of Adult Growth Hormone Deficiency: A Guide for Clinicians

OBJECTIVE

Somapacitan is the first approved and currently the only long-acting growth hormone (GH) formulation in the United States for treatment of adults with growth hormone deficiency (GHD). The aim of this review was to provide a practical approach for clinicians on how to utilize somapacitan in the treatment of adults with GHD.

METHODS

Literature search was performed on PubMed using key words, including adult GHD, long-acting growth hormone, somapacitan, treatment, and management. The discussion of treatment aspects utilizing somapacitan was based on evidence from previous clinical studies and personal experience.

RESULTS

Clinical trial data demonstrated that somapacitan, a once-weekly reversible albumin-binding GH derivative, decreased truncal fat, improved visceral fat and lean body mass, increased insulin-like growth factor-I standard deviation score and exerted neutral effects on glucose metabolism. Overall, somapacitan was well-tolerated, adverse event rates were comparable with daily GH, antisomapacitan or anti-GH antibodies were not detected, and treatment satisfaction was in favor of somapacitan vs daily GH.

CONCLUSION

Somapacitan is an efficacious, safe, convenient and well-tolerated once-weekly long-acting GH formulation that reduces the treatment burden of once-daily GH injections for adults with GHD. This article provides a review of the pharmacology of somapacitan and offers practical recommendations based on previous clinical trial data on how to initiate, dose titration, monitoring and dose adjustments whilst on therapy in adults with GHD. Timing of measurement of serum insulin-like growth factor-I levels, information on administration, recommendations on missed doses, and clinical recommendations on dosing in certain sub-population of patients are also discussed.

Growth Hormone Secretory Capacity Is Associated with Cardiac Morphology and Function in Overweight and Obese Patients: A Controlled, Cross-Sectional Study

Obesity is associated with increased cardiovascular morbidity. Adult patients with growth hormone deficiency (GHD) show morpho-functional cardiological alterations. A total of 353 overweight/obese patients are enrolled in the period between 2009 and 2019 to assess the relationships between GH secretory capacity and the metabolic phenotype, cardiovascular risk factors, body composition and cardiac echocardiographic parameters. All patients underwent GHRH + arginine test to evaluate GH secretory capacity, DEXA for body composition assessment and transthoracic echocardiography. Blood samples are also collected for the evaluation of metabolic parameters. In total, 144 patients had GH deficiency and 209 patients had normal GH secretion. In comparing the two groups, we found significant differences in body fat distribution with predominantly visceral adipose tissue accumulation in GHD patients. Metabolic syndrome is more prevalent in the GHD group. In particular, fasting glycemia, triglycerides and systolic and diastolic blood pressure are found to be linearly correlated with GH secretory capacity. Epicardial fat thickness, E/A ratio and indexed ventricular mass are worse in the GHD group. In the population studied, metabolic phenotype, body composition, cardiovascular risk factors and cardiac morphology are found to be related to the GH secretory capacity. GH secretion in the obese patient seems to be an important determinant of metabolic health.

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.

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

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

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.

Body Composition and Bone Mineral Density in Craniopharyngioma Patients: A Longitudinal Study Over 10 Years

CONTEXT

Patients with craniopharyngioma suffer from obesity and impaired bone health. Little is known about longitudinal changes in body composition and bone mineral density (BMD).

OBJECTIVE

To describe body composition and BMD (change).

DESIGN

Retrospective longitudinal study.

SETTING

Two Dutch/Swedish referral centers.

PATIENTS

Patients with craniopharyngioma (n = 112) with a dual X-ray absorptiometry (DXA) scan available (2 DXA scans, n = 86; median Δtime 10.0 years; range 0.4-23.3) at age ≥ 18 years (58 [52%] male, 50 [45%] childhood onset).

MAIN OUTCOME MEASURES

Longitudinal changes of body composition and BMD, and associated factors of ΔZ-score (sex and age standardized).

RESULTS

BMI (from 28.8 ± 4.9 to 31.2 ± 5.1 kg/m2, P < .001), fat mass index (FMI) (from 10.5 ± 3.6 to 11.9 ± 3.8 kg/m2, P = .001), and fat free mass index (FFMI) (from 18.3 ± 3.2 to 19.1 ± 3.2 kg/m2, P < .001) were high at baseline and increased. Fat percentage and Z-scores of body composition did not increase, except for FFMI Z-scores (from 0.26 ± 1.62 to 1.06 ± 2.22, P < .001). Z-scores of total body, L2-L4, femur neck increased (mean difference 0.61 ± 1.12, P < .001; 0.74 ± 1.73, P < .001; 0.51 ± 1.85, P = .02). Linear regression models for ΔZ-score were positively associated with growth hormone replacement therapy (GHRT) (femur neck: beta 1.45 [95% CI 0.51-2.39]); and negatively with radiotherapy (femur neck: beta -0.79 [-1.49 to -0.09]), glucocorticoid dose (total body: beta -0.06 [-0.09 to -0.02]), and medication to improve BMD (L2-L4: beta -1.06 [-1.84 to -0.28]).

CONCLUSIONS

Z-scores of BMI, fat percentage, and FMI remained stable in patients with craniopharyngioma over time, while Z-scores of FFMI and BMD increased. Higher glucocorticoid dose and radiotherapy were associated with BMD loss and GHRT with increase.

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.

[Current aspects of diagnosis and treatment of adult GH-deficiency]

Adult growth hormone (GH) deficiency (AGHD) is a condition characterized by alterations in body composition, lipid and carbohydrate metabolism, bone mineral density and poor quality of life; however, clinical presentations of AGHD are mostly non-specific. Untreated AGHD is associated with increased cardiovascular morbidity and mortality. Stimulation tests are used for the diagnosis: insulin tolerance test, glucagon stimulation test, growth-hormone releasing hormone and arginine stimulation test. Moreover, in 2017 FDA approved the use of macimorelin (oral GH secretagogue) for the diagnosis of AGHD. In childhood GH-deficiency, apolipoprotein A-IV, CFHR4 (complement factor H-related protein 4) and PBP (platelet basic protein) were identified as potential biomarkers of the disease, however, this was not investigated in AGHD. GH treatment starts from the minimal dose, which allows minimizing the adverse effects. According to published meta-analyses, AGHD treatment generally does not lead to increased risk of malignancy and recurrence of sellar neoplasms in adult patients. Published data on GH receptor polymorphism associations with treatment efficacy remains controversial. Development of long-acting GH formulations is a currect perspective for the increase of treatment compliance.

IGF-1 and cardiovascular disease

Atherosclerosis is an inflammatory arterial pathogenic condition, which leads to ischemic cardiovascular diseases, such as coronary artery disease and myocardial infarction, stroke, and peripheral arterial disease. Atherosclerosis is a multifactorial disorder and its pathophysiology is highly complex. Changes in expression of multiple genes coupled with environmental and lifestyle factors initiate cascades of adverse events involving multiple types of cells (e.g. vascular endothelial cells, smooth muscle cells, and macrophages). IGF-1 is a pleiotropic factor, which is found in the circulation (endocrine IGF-1) and is also produced locally in arteries (endothelial cells and smooth muscle cells). IGF-1 exerts a variety of effects on these cell types in the context of the pathogenesis of atherosclerosis. In fact, there is an increasing body of evidence suggesting that IGF-1 has beneficial effects on the biology of atherosclerosis. This review will discuss recent findings relating to clinical investigations on the relation between IGF-1 and cardiovascular disease and basic research using animal models of atherosclerosis that have elucidated some of the mechanisms underlying atheroprotective effects of IGF-1.