Clinical review: Lessons learned from the hGH era

Growth Hormone Treatment for Non-GHD Disorders: Excitement Tempered by Biology

The success of growth hormone (GH) replacement in children with classical GH deficiency has led to excitement that other causes of short stature may benefit similarly. However, clinical experience has shown less consistent and generally less dramatic effects on adult height, perhaps not surprising in light of increased understanding of GH and growth plate biology. Nonetheless, clinical demand for GH treatment continues to grow. Upon the 20th anniversary of the US Food and Drug Administration's approval of GH treatment for idiopathic short stature, this review will consider the factors underlying the expansion of GH treatment, the biological mechanisms of GH action, the non-GH-deficient uses of GH as a height-promoting agent, biological constraints to GH action, and future directions.

Dilemmas of growth hormone treatment for GH deficiency and idiopathic short stature: defining, distinguishing, and deciding

Worrisome growth can be a sign of underlying pathology but usually reflects healthy variation. It is often recognized through short stature, which is defined by arbitrarily separating height, a physical trait on a continuum, into "normal" and "abnormal." In some cases of worrisome growth, recombinant human growth hormone (rhGH) treatment is indicated to hasten growth/increase height. This review addresses the two most frequently treated indications for rhGH, growth hormone deficiency (GHD) and idiopathic short stature (ISS). A review of worrisome growth itself, of the history of GH treatment, of the blurry line between partial GHD and ISS, of the GH stakeholders, and of the outside pressures involved in these cases demonstrates the ambiguous platform upon which treatment decisions are made. The rhGH treatment decision process can be examined further by considering the three most impactful factors on parental height-related medical decision-making: treatment characteristics, child health, and psychosocial function. While it is important to note that treatment for classical GHD is uncontroversial and supported, treatment decisions for partial GHD and ISS are more complicated and require careful evaluation of both patient needs and the supporting evidence. As the rhGH community grows, physicians, parents, and patients are encouraged to engage in a shared decision-making process to navigate the many challenges facing the GH field. Although this review addresses GHD and ISS specifically, the issues discussed are often applicable to pediatrics as a whole.

Cost-Conscious Growth-Promoting Treatment: When Discretion Is the Better Part of Value

Assessing cost-effectiveness of human growth hormone (hGH) treatment to augment height is complicated by uncertainty about how best to measure its therapeutic effect. Cost-conscious growth promotion practice, however, is possible and likely an emerging practical requisite as health care payers increasingly deny the medical necessity of and restrict support for short stature treatment. The increase in denials is not surprising given the expansion and continued high cost of hGH treatment, debate about the value of such treatment, and universal need to restrain burgeoning health care costs. Renunciation of sweeping payer rejection of hGH-for-height treatment is strengthened by cost-conscious practices that (1) recommend no treatment for most short children and restrict treatment to severe, likely disabling short stature; (2) initiate hGH treatment only after evidence-based informed assent; (3) utilize alternative less costly and less invasive options when possible; (4) minimize hGH treatment duration and dosage; and (5) resist enhancement of normal adult stature. A new era of cost-conscious hGH prescribing that prompts thoughtful restraint in hGH use could help preserve hGH approval for children most in need of treatment.

A Retrospective Analysis of Patients with Short Stature in the South of China between 2007 and 2015

OBJECTIVE

To describe the demographic features of children with short stature and poor growth in the south of China and provide better guidance on clinical strategy and decisions.

STUDY DESIGN

This retrospective, chart review study analyzed children with short stature and poor growth admitted to the Department of Endocrinology of Children's Hospital of Nanjing Medical University from Jan 2007 to Dec 2015.

RESULTS

The chart review yielded 4142 patients, including 2546 boys and 1596 girls (P < 0.001); the number of patients gradually increased per year from 2007 to 2015. There was an upward trend in the average levels of height standard deviations (SDs) during the study period (P < 0.001), both in males (P < 0.001) and females (P < 0.001). Mean height SDs were smaller in females (-2.42±1.09) than males (-2.33±1.03; P = 0.01). The percentage of females admitted at normal height (33.83%) was lower than that of males (37.20%; P = 0.028). The peak age range of hospitalization in males was 10-12 years of age, while females were generally admitted earlier-8-10 years.

CONCLUSIONS

There was an increasing tendency to focus on children's height. Parents and pediatricians were recommended to pay more attention to the treatment needs of girls while avoiding excessive treatment of those who merely appear not to be tall enough without a clear medical issue related to growth, especially for boys.

Growth Hormone Therapy for a Child With Severe Cognitive Impairment

The expansion of growth hormone therapy over the last 3 decades has allowed for treatment of short stature for more children, resulting in increased height for many. However, treatment of idiopathic short stature remains controversial. Treatment decisions for disabled children with idiopathic short stature are even more complicated. We discuss a specific case of short stature in a disabled child and grapple with the ethical issues involved in the use of growth hormone.

A genetic approach to evaluation of short stature of undetermined cause

Short stature is a common presentation to paediatric endocrinologists. After exclusion of major endocrine or systemic disease, most children with short stature are diagnosed based on a description of their growth pattern and the height of their parents (eg, familial short stature). Height is a polygenic trait and genome-wide association studies have identified many of the associated genetic loci. Here we review the application of genetic studies, including copy number variant analysis, targeted gene panels, and whole-exome sequencing in children with idiopathic short stature. We estimate 25-40% of children diagnosed with idiopathic short stature could receive a molecular diagnosis using these technologies. A molecular diagnosis for short stature is important for affected individuals and their families and might inform treatment decisions surrounding use of growth hormone or insulin-like growth factor 1 therapy.

Long-term safety of growth hormone-A combined registry analysis

OBJECTIVES

Preliminary data from the French cohort of the Safety and Appropriateness of Growth hormone treatments in Europe (SAGhE) study raised concerns regarding the safety of recombinant human GH, suggesting that GH may increase mortality and incidence of stroke in patients treated during childhood for GH deficiency or short stature. We evaluated published safety data, focusing on mortality, neoplasms, cerebrovascular events and diabetes across a number of large-scale pharmaceutical company GH registries.

DESIGN

A literature review was conducted using PubMed, EMBASE and Google Scholar to identify all relevant safety data from manufacturers' GH registries published between 1988 and April 2016. Results were hand-sorted to exclude nonrelevant publications; bibliographic references from retrieved articles were evaluated for any additional references.

RESULTS

The published data do not support an increased risk of mortality in children or adults treated with GH. There was no evidence of an increased risk of stroke, new malignancy, leukaemia, nonleukaemic extracranial tumours or recurrence of intracranial malignancy in patients without risk factors. The risk of a second neoplasm is increased, particularly if patients have received radiation therapy for a central nervous system tumour. There may be an increased risk of type 2 diabetes in GH-treated patients, but this appears to be confined to those with pre-existing risk factors.

CONCLUSIONS

Patients with risk factors for malignancy or type 2 diabetes should be treated with caution and monitored during follow-up, but current published data provide reassurance on the long-term safety profile of GH in patients receiving GH treatment.

Growth Promotion Ethics and the Challenge to Resist Cosmetic Endocrinology

The advancement of "human growth hormone (hGH)-for-height" - increasing height attainment in children short for reasons other than GH deficiency - arose from intuitive, deep-seated assumptions about the disability of short stature, its improvement with hGH-mediated height gain, and the safety of escalating dosages of hGH in healthy children. Evidence challenging these assumptions now strengthens criticism of hGH-for-height as cosmetic endocrinology. To counter this characterization, collective acceptance of guidelines is needed that advise nontreatment of the vast majority of short children, support strategies that minimize treatment duration and dosage, and restrain enhancement of normal adult stature. Through a clinical case analysis, ethical issues underlying these recommendations are explored. These include duties to provide informed assent and re-assent, protect children from unnecessary treatment, consider fairness to nontreated children, and allocate healthcare resources responsibly. Informed assent for hGH-for-height should ensure awareness of modest, variable height gain expectations, limited evidence for psychosocial benefit, ongoing studies for potential posttreatment adverse effects, and options for less expensive/invasive approaches, including nontreatment and counseling. Approaching growth pro-motion in this way fosters therapeutic restraint, resists the al lure of enhancement therapy, and minimizes contributions to society's perception that to be taller is to be better.
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WHO and national lists of essential medicines in Mexico, Central and South America, and the Caribbean: are they adequate to promote paediatric endocrinology and diabetes care?

Paediatric endocrinology and diabetes is a paediatric specialty with less common conditions and higher cost medicines. Access to medicines for our specialty in low and middle income countries remains limited. We analysed the content of the WHO (children and adults) and of all available national Model Lists of Essential Medicines (EMLs) for Mexico, the Caribbean, Central and South America from a paediatric endocrinology and diabetes standpoint. A master list of medicines deemed necessary in paediatric endocrinology and diabetes was established and compared with the WHO and national EMLs, taking into account the gross national income. The WHO EMLs, which are largely recognised as an international benchmark and drive the content of the national EMLs, included many but not all medicines present on our master list. Interestingly, several national EMLs from richer countries included medicines that were not present in the WHO EMLs. Our analysis suggests that these medicines could be considered by the WHO for inclusion in their EMLs, which may promote the adoption of more medicines by individual countries. We also propose several changes to the WHO and national EMLs that could facilitate access to medicines in our specialty: age cut-off for a child using physical maturity rather than a set age limit; greater standardisation of the formatting of the national EMLs for easier comparison and collaborations between countries; greater emphasis on age-specificity and population-specificity for some medicines; and formatting of the EMLs in a disease-focused manner rather than as individual medicines.

Towards optimal treatment with growth hormone in short children and adolescents: evidence and theses

Treatment with growth hormone (GH) has become standard practice for replacement in GH-deficient children or pharmacotherapy in a variety of disorders with short stature. However, even today, the reported adult heights achieved often remain below the normal range. In addition, the treatment is expensive and may be associated with long-term risks. Thus, a discussion of the factors relevant for achieving an optimal individual outcome in terms of growth, costs, and risks is required. In the present review, the heterogenous approaches of treatment with GH are discussed, considering the parameters available for an evaluation of the short- and long-term outcomes at different stages of treatment. This discourse introduces the potential of the newly emerging prediction algorithms in comparison to other more conventional approaches for the planning and evaluation of the response to GH. In rare disorders such as those with short stature, treatment decisions cannot easily be deduced from personal experience. An interactive approach utilizing the derived experience from large cohorts for the evaluation of the individual patient and the required decision-making may facilitate the use of GH. Such an approach should also lead to avoiding unnecessary long-term treatment in unresponsive individuals.

Treatment of children and adolescents with idiopathic short stature

Idiopathic short stature (ISS) is defined as shortness in childhood without a specific cause. ISS may be familial or nonfamilial and may be associated with or without delay of pubertal development. Treatment can be considered in an attempt to reduce the psychological burden caused by short stature in childhood and adult life. If counselling alone is not sufficient, medical modifications of the growth process can be attempted. In cases with pubertal delay, sex steroids, such as testosterone and oxandrolone, can favourably influence height velocity and growth tempo, although adult height is not affected. Medications that prolong the process of growth--for example, gonadotropin-releasing hormone agonists or aromatase inhibitors--might increase adult height, but findings to date are still experimental. Growth hormone therapy is approved for the treatment of very short children with reduced adult height expectation, as evidence has accumulated that this therapy can increase height in childhood and in adult life. Sensitivity to growth hormone is impaired in patients with ISS; therefore, doses higher than a replacement dose have to be applied. This treatment still needs to be optimized in terms of efficacy, cost-effectiveness and long-term safety. A debate is ongoing concerning the psychological benefit of height increase, with clinicians warning against the medicalization of a deviation in height.

Debate: idiopathic short stature should be treated with growth hormone

In this paper we outline the case for and against the treatment of idiopathic short stature with growth hormone. Drs Ambler and Fairchild argue that many of those with 'idiopathic' short stature are not 'short, normal children' and will ultimately receive molecular diagnoses. They also argue that there is a subset of children who suffer negative psychosocial consequences of their stature for whom growth hormone therapy is effective. Growth hormone has a very good safety record and is likely to be as cost-effective in idiopathic short-stature as in some other conditions that are currently funded. Dr Wilkinson counters that short stature is not associated with physical or psychological illness, and that there is no evidence that growth hormone improves psychological or physical wellbeing. Moreover, growth hormone for idiopathic short stature represents a form of enhancement rather than treatment, and is not a fair use of resources. Socially mediated disadvantage should be treated by attention to prejudice and not by hormone treatment.