Growth hormone therapy for the short normal child: who needs it and who wants it? The case against growth hormone therapy

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.

A randomized pilot trial of growth hormone with anastrozole versus growth hormone alone, starting at the very end of puberty in adolescents with idiopathic short stature

BACKGROUND

When given during the course of puberty, anastrozole (A), an aromatase inhibitor, has been shown to increase the predicted adult height (PAH) of GH-deficient (GHD) boys treated with recombinant human growth hormone (rhGH). Our study questioned whether this treatment could retain some of its effects in non-GHD adolescent boys if started only at the very end of puberty, a time when rhGH treatment is denied to short adolescents who have almost reached their final height.

OBJECTIVE

To explore the effect on adult height of a combination of rhGH and A, compared with rhGH alone, at the end of puberty in boys with idiopatic short stature (ISS).

METHODS

A prospective randomized study comparing rhGH + A and rhGH was conducted in 24 healthy adolescent boys aged 15.2 ± 1.2 yrs with serum testosterone at adult levels and a faltering growth velocity <3.5 cm/yr leading to a predicted adult height (PAH) <2.5 SDS. Treatments were stopped when growth velocity became <10 mm in 6 months or when height was close to 170 cm. A historical group of ISS adolescents (N = 17) matched for puberty and growth was used for comparison.

RESULTS

IGF1 levels remained within normal limits in all treated patients. Mean treatment duration was 19 months in the rhGH + A group and 11.5 months in the rhGH group (P = 6.10(-4)). Adult height reached 168.4 ± 2.6 cm in the rhGH + A group and 164.2 ± 5.6 cm in the rhGH group (P < 0.02). Adult height was 160.1 ± 2.8 cm in the historical controls.

CONCLUSION

A combination of rhGH and A, started at the very end of puberty, seems to allow boys with ISS to reach a greater adult height than rhGH alone. Larger trials are needed to confirm this preliminary observation.

Growth hormone significantly increases the adult height of children with idiopathic short stature: comparison of subgroups and benefit

BACKGROUND

Children with Idiopathic Short Stature do not attain a normal adult height. The improvement of adult height with treatment with recombinant human growth hormone (rhGH), at doses of 0.16 to 0.28 mg/kg/week is modest, usually less that 4 cm, and they remain short as adults. The benefit obtained seems dose dependent and benefits of 7.0 to 8.0 cm have been reported with higher doses of 0.32 to 0.4 mg/kg/week, but the number of studies is limited. The topic has remained controversial.

OBJECTIVE

The objective was to conduct a retrospective analysis of our experience with 123 children with ISS treated with 0.32 ± 0.03 mg/kg/week of rhGH, with the aim of comparing the different subgroups of non-familial short stature, familial short stature, normal puberty, and delayed puberty and to assess the benefit by comparison with 305 untreated historical controls, from nine different randomized and nonrandomized controlled studies.

RESULTS

Eighty eight of our children (68 males and 20 females) attained an adult height or near adult height of -0.71 SDS (0.74 SD) (95% CI, -0.87 to -0.55) with a benefit over untreated controls of 9.5 cm (7.4 to 11.6 cm) for males and 8.6 cm (6.7 to 10.5 cm) for females. In the analysis of the subgroups, the adult height and adult height gain of children with non-familial short stature were significantly higher than of familial short stature. No difference was found in the cohorts with normal or delayed puberty in any of the subgroups, except between the non-familial short stature and familial short stature puberty cohorts. This has implications for the interpretation of the benefit of treatment in studies where the number of children with familial short stature in the controls or treated subjects is not known. The treatment was safe. There were no significant adverse events. The IGF-1 values were essentially within the levels expected for the stages of puberty.

CONCLUSION

Our experience was quite positive with normalization of the heights and growth of the children during childhood and the attainment of normal adult heights, the main two aims of treatment.

Characteristics of the short children referred to an academic paediatric endocrine clinic in Greece

AIM

To describe the characteristics of short children in relation to gender and the various diagnoses.

METHODS

All new patients of Greek origin that were referred to our institution in the years 2007 and 2008 for evaluation of short stature were included in the study. Children were categorized according to the severity of their short stature in those with height standard deviation score (HSDS) ≤ -3 and HSDS > -3.

RESULTS

Two hundred ninety-five children (162 boys and 133 girls, ratio 1.2) were referred. HSDS of boys was -2.3 (0.6) and of girls -2.1 (0.5), P= 0.004. Girls had shorter parents, and the predicted adult HSDS was also shorter for girls -1.7 (0.8) than for boys -1.35 (0.76), P= 0.003. Seventy per cent of the children of both sexes had familial short stature (FSS), constitutional delay of growth or a combination of the two conditions. About 10% presented the auxological and biochemical criteria for growth hormone deficiency (GHD). In addition, 11.8% had a HSDS ≤ -3, the most common diagnosis being GHD (36.1%); the less severely short children most commonly presented FSS (41.2%).

CONCLUSIONS

There is no gender bias in referrals for short stature in Greece. About 70% of children of both sexes presented FSS or constitutional delay of growth or a combination of the two conditions, whereas GHD was diagnosed in about 10% of the children. Normal variants of growth were present in about 80% of children with HSDS > -3, but in only 40% when HSDS was ≤ -3.

Managing idiopathic short stature: role of somatropin (rDNA origin) for injection

Idiopathic short stature (ISS) is a term that describes short stature in children who do not have growth hormone (GH) deficiency and in whom the etiology of the short stature is not identified. Between 1985 and 2000, more than 40 studies were published regarding GH therapy for ISS. Only 12 of these had data to adult height, of which only 4 were controlled studies. A subsequent placebo-controlled study that followed subjects to adult height indicated that there was a gain of 3.7–7.5 cm in height with GH treatment. In 2003, the US Federal Drug Administration (FDA) approved GH for treatment of short stature. Even before FDA approval, patients with ISS made up about 20% of patients in GH databases, which is largely unchanged since FDA approval. There remains some controversy as to whether GH should be used to treat ISS. This controversy centers on the fact that there has been no definitive demonstration that short stature results in a disadvantage or problems with psychological adjustment, and thus, no demonstration that GH therapy results in improvement in quality of life.

Idiopathic short stature: management and growth hormone treatment

In the management of ISS auxological, biochemical, psychosocial and ethical elements have to be considered. In boys with constitutional delay of growth and puberty androgens are effective in increasing height and sexual characteristics, but adult height is unchanged. GH therapy is efficacious in increasing height velocity and adult height, but the inter-individual variation is considerable. The effect on psychosocial status is uncertain. Factors affecting final height gain include GH dose, height deficit in comparison to midparental height, age and first year height velocity. In case of a low predicted adult height at the onset of puberty, addition of a GnRH analogue can be considered. Although GH therapy appears safe, long-term monitoring is recommended.

"Anything you can do, I can do bigger?": the ethics and equity of growth hormone for small normal children

This paper argues against the use of growth hormone (GH) for small normal children ("idiopathic" short stature) with the following considerations: ethical (philosophical) grounds, cost-economic implications, and the rationale for treating normal physiological variation with a potent pharmacological agent. The author would prefer to see health and economic resources being directed to correct nutritional and environmental deprivation among underprivileged groups in preference to providing GH injections for small normal children.

Growth hormone treatment in non-growth hormone-deficient short children

The unlimited availability of GH obtained by recombinant DNA technology has allowed optimization of treatment in GH-deficient (GHD) children. At the same time it has prompted a number of studies in conditions not characterized by GHD such as Turner syndrome, intrauterine growth retardation, chronic renal failure and other chromosomal and genetic abnormalities associated with short stature. Several controlled and uncontrolled studies have now reported the adult height of patients with short stature and normal GH secretion. Critical reviewing of the data shows that some short non-GHD children may benefit from a prolonged treatment with GH. However, further studies are needed in order to be able to identify the subjects for whom treatment is really beneficial.

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

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

Human growth hormone and gonadotropin releasing hormone analog combination therapy increases predicted height in short normal girls

The "short normal" child constitutes a real challenge for the pediatric endocrinologist. In a subgroup of short normal children, puberty starts at a normal age but with low height, and hence, the final height is expected to be quite compromised. Efforts to improve the outcome in this group have been made in the past with equivocal results. We present the growth data of 8 short girls with normal growth hormone values on provocative testing and low height at puberty initiation. At intervention the height and the stage of puberty were 129.3 +/- 5 cm and II to III, respectively, and the predicted height was 148.8 +/- 2.6 cm. Gonadotropin releasing hormone analog, triptorelin (3.6 +/- 0.5 microg/kg/day) and growth hormone (0.5 IU/kg/week) were used in different sequential order and simultaneously in each child. The mean total treatment period was 47.6 +/- 11.2 months. The mean predicted and the mean final height in the total group were 148.8 +/- 2.6 and 154.5 +/- 3.6 cm, respectively (p:0.028). The final height did not differ from the target height (154.8 +/- 8 cm versus 154.5 +/- 3.6 cm), while in 4 children, the final height was greater than the target height. The height gain (delta Final height - Predicted height) was 5.7 +/- 1.3 cm. If we analyze separately the girls in whom growth hormone was started first and gonadotropin releasing hormone analog followed versus those who started the analog first, the delta Final height - Predicted height was 8 +/- 3 cm in the former and 4.8 +/- 3.1 cm in the latter (p:0.03). It seemed that the difference was accounted for by duration of growth hormone therapy (51.3 +/- 10.6 months versus 28.6 +/- 10.6 months) (p:0.026), rather than by other factors. In conclusion, under the conditions of the present study, the combination of puberty arrest and growth hormone therapy significantly improved predicted height. The most significant determinant of the height gain was the duration of growth hormone therapy.

The psychosocial consequences of short stature: a review of the evidence

The advent of biosynthetic growth hormone (GH) has been accompanied by a transformation in the clinical management of youths with short stature. An important--if not always explicitly stated--goal of endocrine therapies is an improvement in the psychological adaptation of individuals with short stature. Negative stereotypes regarding short stature constitute a potential source of psychosocial stress for the affected child and, in turn, the entire family. Nevertheless, studies have demonstrated that the psychological adaptation of individuals who are shorter than average is largely indistinguishable from others, whether in childhood, adolescence or adulthood. "Short stature" as an isolated physical characteristic appears to hold little value as a predictor of the individual's psychological adaptation or quality of life. In order to avoid the unwarranted medicalizing of healthy short stature, clinicians would be well advised to incorporate factors beyond auxology in the decision-making algorithm when selecting and preparing patients for possible growth-promoting therapies.

Quality of life and self-esteem in children treated for idiopathic short stature

OBJECTIVE

Changes in health-related quality of life (HRQOL) and self-esteem were studied in children with idiopathic short stature (ISS) participating in a study on the effect of growth hormone treatment.

STUDY DESIGN

Prepubertal children (n = 36) with ISS were randomly assigned to a treatment or control group. Children with ISS, their parents, and the pediatrician completed HRQOL and self-esteem questionnaires 3 times in 2 years.

RESULTS

At the start, children with ISS did not have lower scores than the norm population, except for social functioning HRQOL. The pediatrician reported an improvement of HRQOL in the treatment group, the parents reported no change, and the children in the treatment group reported the same, or sometimes even worse, HRQOL or self-esteem than the control group. Changes related to the child's satisfaction with height and hardly to growth itself.

CONCLUSION

The assumption that growth hormone treatment improves HRQOL in children with ISS could not be supported in this study.

Behavioral evaluation of GH treatment in short statured children and adolescents: findings from a pilot study

A cohort of 93 short-statured children and adolescents undergoing GH treatment were evaluated with respect to behavior, emotions, and attitudes. The sample consisted of patients suffering from either idiopathic GH deficiency or neurosecretory dysfunction (no.=47), Turner syndrome (no.=20), organic GH deficiency due to brain tumors (no.=10), or other etiologies (no.=16). The Child Behavior Checklist (CBCL) together with a brief Evaluation of Treatment Questionnaire (ETQ) were filled out by the patient's parents. These evaluations were performed at onset and after 12 and 24 months of GH treatment, respectively. There was a highly significant but clinically small decline of behavioral abnormalities over time and parents saw major benefits of GH treatment in the total group of patients. The behavioral changes over time were independent of diagnostic category, gender, height velocity, puberty and age.

Short normal stature and psychosocial disadvantage: a critical review of the evidence

Physicians and parents alike are under increasing pressure to identify and to treat short stature, but intervention implies the presence of some pathology, physical or psychological, that can be corrected. Where there is true GH deficiency, the argument for replacement is uncontroversial. It is less compelling where GH 'insufficiency' is diagnosed. In the case of the short, but otherwise normal, child the indications for therapy are even less clear. Short stature, per se, is clearly not a disease, in spite of the perception by some practitioners that the rate of growth of such children is abnormal. Short stature is, however, commonly perceived to be associated with social and psychological disadvantage, yet many of these misperceptions about short stature can be challenged. A critical review of the literature pertaining to the psychosocial correlates of short stature uncovers much flawed evidence. Most importantly, the belief, widely held by paediatricians, that short children are likely to be significantly disadvantaged, has been founded largely on data from clinic-referred samples. In such studies, children with real (or perceived) behavioural or academic problems are likely to be overly represented. Publications arising from such studies, however, inevitably lead to an increase in the demand for treatment both from and for those who previously had no such concern. In contrast, data from a well controlled, prospective population-based study suggest the essential normality of the short normal child. Parents and children alike should be reassured by these findings. In the absence of clear pathology, physical or psychological, GH therapy for short but otherwise normal children must therefore, in most cases, be deemed cosmetic, raising issues as to the ethics of so-called "plastic endocrinology".

Not being the wrong size

Size regulation is a never-ending problem. Many of us worry that parts of ourselves are too big whereas other parts are too small. How organisms--and their tissues--are programmed to be a specific size, how this size is maintained, and what might cause something to become the wrong size, are key problems in developmental biology. But what are the mechanisms that regulate the size of multicellular structures?