Growth hormone treatment of short children born small for gestational age or with Silver-Russell syndrome: results from KIGS (Kabi International Growth Study), including the first report on final height

Body Composition and Metabolism in Adults With Molecularly Confirmed Silver-Russell Syndrome

CONTEXT

Low birth weight, as seen in Silver-Russell syndrome (SRS), is associated with later cardiometabolic disease. Data on long-term outcomes and adult body composition in SRS are limited.

OBJECTIVE

To evaluate body composition and metabolic health in adults with SRS.

METHODS

This was an observational study of 25 individuals with molecularly confirmed SRS, aged ≥ 18 years, from research facilities across the UK. Body composition and metabolic health were assessed at a single appointment. Individuals with SRS were compared with unaffected men and women (from the Southampton Women's Survey [SWS]). Fat mass, lean mass, bone mineral density (BMD), blood pressure, lipids, and blood glucose were measured.

RESULTS

Twenty-five adults with SRS were included (52% female). The median age was 32.9 years (range, 22.0 to 69.7). Fat percentage was greater in the SRS group than the SWS cohort (44.1% vs 30.3%, P < .001). Fat mass index was similar (9.6 vs 7.8, P = .3). Lean mass percentage (51.8% vs 66.2%, P < .001) and lean mass index (13.5 kg/m2 vs 17.3 kg/m2, P < .001) were lower in the SRS group than the SWS cohort. BMD was lower in the SRS group than the SWS cohort (1.08 vs 1.24, P < .001; all median values). Total cholesterol was ≥ 5 mmol/L in 52.0%. Triglyceride levels were ≥ 1.7 mmol/L in 20.8%. Fasting blood glucose levels were ≥ 6.1 mmol/L in 25.0%. Hypertension was present in 33.3%.

CONCLUSION

Adults with SRS have an unfavorable body composition and predisposition to cardiometabolic disease. These results support the need for a health surveillance strategy to mitigate adverse outcomes.

The long-term growth, cost-effectiveness, and glycemic effects of growth hormone therapy on children born small for gestational age over 10 years: a retrospective cohort study

OBJECTIVES

We aimed to report our 10-year experience of treating short children born small for gestational age (SGA) by comparing the long-term growth, metabolic safety, and cost-effectiveness of recombinant human growth hormone (rhGH) therapy in short children born SGA with those in rhGH-treated children with growth hormone deficiency (GHD) and Turner syndrome.

METHODS

We performed a 10-year retrospective cohort study at King Saud University Medical City. We included children aged 3-16 years who received rhGH for GHD, SGA, or Turner syndrome for >1 year.

RESULTS

A total of 166 children received rhGH therapy for GHD, 58 for SGA, and 16 for Turner syndrome. During the last study visit, the average height change was 21 cm for GHD children and 14 cm for children born SGA (p-value <0.001). The height SDS change was 0.84 for GHD children and 0.55 for SGA children (p-value=0.004). The average cost-effectiveness ratios for treating GHD and SGA children were USD 1,717.22 and USD 1,157.19 per centimeter gained, respectively. Moreover, the mean incremental cost-effectiveness ratio for GHD vs. SGA patients was USD 2,820.39 per centimeter gained. Dysglycemia developed in 70 patients: 43 (36.44%), 22 (40.74%), and 5 (13%) in the GHD, SGA, and Turner syndrome groups, respectively.

CONCLUSIONS

rhGH is effective in height improvement of short children. However, pursuing rhGH treatment for children born SGA requires a shared decision-making approach to balance the modest benefit of final adult height gain with the long-term metabolic effects, considering the acceptable costs on the Saudi healthcare system.

Human Growth and Growth Hormone: From Antiquity to the Recominant Age to the Future

Since antiquity Man has been fascinated by the variations in human (and animal) growth. Stories and art abound about giants and little people. Modern genetics have solved some of etiologies at both extremes of growth. Serious study began with the pathophysiology of acromegaly followed by early attempts at treatment culminating in modern endoscopic surgery and multiple pharmacologic agents. Virtually at the same time experiments with the removal of the pituitary from laboratory animals noted the slowing or stopping of linear growth and then over a few decades the extraction and purification of a protein within the anterior pituitary that restored, partially or in full, the animal's growth. Human growth hormone was purified decades after those from large animals and it was noted that it was species specific, that is, only primate growth hormone was metabolically active in primates. That was quite unlike the beef and pork insulins which revolutionized the care of children with diabetes mellitus. A number of studies included mild enzymatic digestion of beef growth hormone to determine if those "cores" had biologic activity in primates and man. Tantalizing data showed minimal but variable metabolic efficacy leading to the "active core" hypothesis, for these smaller peptides would be amenable to peptide synthesis in the time before recombinant DNA. Recombinant DNA changed the landscape remarkably promising nearly unlimited quantities of metabolically active hormone. Eight indications for therapeutic use have been approved by the Food and Drug Administration and a large number of clinical trials have been undertaken in multiple other conditions for which short stature in childhood is a sign. The future predicts other clinical indications for growth hormone therapy (and perhaps other components of the GH?IGF-1 axis), longer-acting analogues and perhaps a more physiologic method of administration as virtually all methods at present are far from physiologic.

Growth and metabolic effects of long-term recombinant human growth hormone (rhGH) treatment in short children born small for gestational age: GH-RAST study

Objectives To study the efficacy and influence on metabolism of recombinant human growth hormone (rhGH) treatment in short children born small for gestational age (SGA). Methods Retrospective, observational, multicenter study in 305 short children born SGA, treated with rhGH during a mean ± SD of 5.03 ± 1.73 years at a mean ± SD dose of 37 ± 8 μg/kg/day. Auxological and metabolic assessment including glucose and lipids profile were collected. Results Mean ± SD age at the start of treatment was 7.11 ± 2.78 years. Height and weight improved significantly until the end of treatment from mean -2.72 (CI95%: -2.81 to -2.63) standard deviation score (SDS) to -1.16 (CI95%: -1.44 to -0.88) SDS and from -1.62 (CI95%: -1.69 to -1.55) SDS to -0.94 (CI95%: -1.14 to -0.74) SDS respectively. Mean height gain was 1.27 (CI95%: 0.99-1.54) SDS. Prepubertal patients showed higher height gain than pubertal children (mean [CI95%] = 1.44 [CI95%: 1.14-1.74] vs. 0.73 [CI95%: 0.22-1.24], p=0.02). Height gain SDS during treatment negatively correlated with chronological age (CA) and bone age (BA) delay and positively correlated with duration of treatment, height gain during first year of treatment, years on prepubertal treatment and height SDS from target height (TH). Glucose, insulin, and triglycerides increased significantly but remained within the normal range. Total and LDL-cholesterol decreased significantly, and HDL-cholesterol remained unchanged. Conclusions rhGH treatment in short SGA children effectively normalized height in most of the patients and showed a safe metabolic profile. Children who benefit the most are those with greater height SDS distance from TH, BA delay, longer duration of treatment and prepubertal treatment initiation.

Evaluation of Changes in Insulin Sensitivity in Prepubertal Small for Gestational Age Children Treated with Growth Hormone

BACKGROUND

Although growth hormone (GH) therapy for children born small for gestational age (SGA) has been approved for many years, there are still concerns about increasing their risk for insulin resistance and diabetes mellitus type 2. Monitoring of glucose homeostasis is therefore generally recommended, but there is no consensus on either the methods or consequences.

METHODS AND AIMS

The aim of our study was to analyze the oral Glucose Tolerance Tests (oGTTs) which were performed yearly from baseline to 4 years of GH therapy in a collective of 93 SGA children, who were prepubertal during the whole follow-up. We looked for correlations with auxological and laboratory data as well as predictive baseline results for glucose homeostasis during further treatment.

RESULTS

While glucose levels remained constant, insulin secretion increased from baseline to the first year of GH therapy. Insulin sensitivity index (ISI) showed no significant change afterwards; HOMA1, HOMA2, and QUICKI stabilized after the second year. For all indices mean values never reached pathological levels and no cases of diabetes mellitus were induced. Higher gestational age, lower birth length, and older age at start of GH therapy were associated with lower insulin sensitivity. No predictive factors for later insulin resistance could be found.

CONCLUSION

As expected, in GH-treated prepubertal SGA children insulin resistance was induced, but not to pathological levels. No special risk factors for disturbed glucose homeostasis could be identified. Based on our opinion, performing oGTTs in GH-treated SGA children at baseline and in puberty should remain mandatory, but the current study recommendations regarding further surveillance of glucose homeostasis are questionable.

Children Born Small for Gestational Age: Differential Diagnosis, Molecular Genetic Evaluation, and Implications

Children born small for gestational age (SGA), defined as a birth weight and/or length below -2 SD score (SDS), comprise a heterogeneous group. The causes of SGA are multifactorial and include maternal lifestyle and obstetric factors, placental dysfunction, and numerous fetal (epi)genetic abnormalities. Short-term consequences of SGA include increased risks of hypothermia, polycythemia, and hypoglycemia. Although most SGA infants show catch-up growth by 2 years of age, ∼10% remain short. Short children born SGA are amenable to GH treatment, which increases their adult height by on average 1.25 SD. Add-on treatment with a gonadotropin-releasing hormone agonist may be considered in early pubertal children with an expected adult height below -2.5 SDS. A small birth size increases the risk of later neurodevelopmental problems and cardiometabolic diseases. GH treatment does not pose an additional risk.

Craniofacial morphology and dental maturity in children with reduced somatic growth of different aetiology and the effect of growth hormone treatment

Children with reduced somatic growth may present various endocrinal diseases, especially growth hormone deficiency (GHD), idiopathic short stature (ISS), chromosomal aberrations, or genetic disorders. In an attempt to normalize the short stature, growth hormone (GH) is administered to these children. The aim of this literature review was to collect information about the craniofacial morphology and dental maturity in these children and to present the existing knowledge on the effect of GH treatment on the above structures.

This review demonstrated that regardless of the origin of the somatic growth retardation, these children show similar craniofacial features, such as short length of the cranial base and the mandible, increased lower facial height, retropositioned mandible, and obtuse gonion angle. On the other hand, dental maturation does not demonstrate a specific pattern. Except for the above findings, muscle alterations seem to be present in individuals with short stature, who present low body muscle mass and strength, while studies on their craniofacial muscles seem to be lacking. After GH administration, the exact amount and pattern of craniofacial growth is unpredictable; however, the facial convexity decreases, mandibular length increases, and posterior facial height increases, while tooth eruption remains unaffected. Thus, it is of great importance to gain more insight into the craniofacial growth of treated and untreated children with reduced somatic growth so that the influence of GH therapy on the various craniofacial structures could be ascertained and proper orthodontic treatment could be selected.

[Effects of growth hormone treatment on anthropometrics, metabolic risk, and body composition variables in small for gestational age patients]

INTRODUCTION AND OBJECTIVES

Small for gestational age (SGA) children without catch-up growth can benefit from treatment with growth hormone (rhGH). However, they should be monitored very closely because they are at increased risk of metabolic syndrome.

MATERIAL AND METHOD

A group of 28 SGA children with a mean age of 8.79 years and undergoing treatment with rhGH were selected for evaluation. Over the course of 4 years, an annual evaluation was performed on the anthropometric variables (weight, height, body mass index [BMI], growth rate, blood pressure and waist perimeter), metabolic risk variables (glycaemia, glycosylated haemoglobin, cholesterol ratio, insulinaemia, insulin-like growth factor 1[IGF1], IGF binding protein-3 [IGFBP-3], IGF1/IGFBP3 ratio, and HOMA index), and body composition variables.

RESULTS

Treatment with rhGH was associated with a significant increase in height (-2.76±.11 SD to -1.53±.17 SD, P=.000), weight (-1.50±.09 SD to -1.21±.13 SD; P=.016), and growth rate (-1.43±.35 SD to .41±.41 SD; P=.009), without a corresponding change in the BMI. Insulinaemia (9.33±1.93mU/ml to 16.55±1.72mU/ml; P=.044) and the HOMA index (3.63±.76 to 6.43±.67; P=.042) increased, approaching insulin resistance levels. No changes were observed in the lipid profile. Body composition changes were observed, with a significant increase in lean mass (73.19±1.26 to 78.74±1.31; P=.037), and a reduction of fat mass (26.81±1.26 to 21.26±1.31; P=.021).

CONCLUSION

Treatment with rhGH is effective for improving anthropometric variables in SGA patients who have not experienced a catch-up growth. It also produces changes in body composition, which may lead to a reduction in risk of metabolic syndrome. However, some insulin resistance was observed. It is important to follow up this patient group in order to find out whether these changes persist into adulthood.

Efficacy and safety of growth hormone treatment for children born small for gestational age

Recombinant growth hormone (GH) is an effective treatment for short children who are born small for gestational age (SGA). Short children born SGA who fail to demonstrate catch-up growth by 2-4 years of age are candidates for GH treatment initiated to achieve catch-up growth to a normal height in early childhood, maintain a normal height gain throughout childhood, and achieve an adult height within the normal target range. GH treatment at a dose of 35-70 µg/kg/day should be considered for those with very marked growth retardation, as these patients require rapid catch-up growth. Factors associated with response to GH treatment during the initial 2-3 years of therapy include age and height standard deviation scores at the start of therapy, midparental height, and GH dose. Adverse events due to GH treatment are no more common in the SGA population than in other conditions treated with GH. Early surveillance in growth clinics is strongly recommended for children born SGA who have not caught up. Although high dose of up to 0.067 mg/kg/day are relatively safe for short children with growth failure, clinicians need to remain aware of long-term mortality and morbidity after GH treatment.

Comparative evaluation of short-term biomarker response to treatment for growth hormone deficiency in Chinese children with growth hormone deficiency born small for or appropriate for gestational age: a randomized phase IV open-label study

OBJECTIVES

To compare the response between Chinese children with growth hormone deficiency (GHD) born either small for gestational age (SGA) or appropriate for gestational age (AGA) after 4 weeks of recombinant human growth hormone (r-hGH) therapy.

METHODS

This was a phase IV, open-label, multicenter, interventional study (NCT01187550). Prepubertal children with GHD received open-label treatment with daily r-hGH (0.033 mg/kg) for 4 weeks. Serum levels of insulin-like growth factor I (IGF-I) and insulin-like growth factor-binding protein 3 (IGFBP3), and metabolic markers (including fasting glucose, insulin, total cholesterol, and homeostasis model assessment of insulin resistance) were assessed at baseline and after 4 weeks of treatment, and were analyzed according to patient subgroup (SGA or AGA).

RESULTS

A total of 205 children with GHD (mean age 10.4 years; 175 AGA, 30 SGA) were included in the analysis. Mean baseline serum IGF-I and IGFBP3 standard deviation scores (SDS) across the whole patient population were lower than the population norms (mean values: -2.1 SDS for IGF-I and -1.2 SDS for IGFBP3), with no significant differences between the two patient subgroups. After 4 weeks, IGF-I and IGFBP3 levels increased by 1.0 SDS (p < 0.001) and 0.34 SDS (p < 0.001), respectively, but no significant differences were found between the two patient subgroups for growth-related or metabolic markers.

CONCLUSIONS

For children with GHD born SGA, IGF-I and IGFBP3 are short-term biomarkers of responsiveness to treatment with growth hormone, as for children with GHD born AGA.

Prediction models for short children born small for gestational age (SGA) covering the total growth phase. Analyses based on data from KIGS (Pfizer International Growth Database)

BACKGROUND

Mathematical models can be developed to predict growth in short children treated with growth hormone (GH). These models can serve to optimize and individualize treatment in terms of height outcomes and costs. The aims of this study were to compile existing prediction models for short children born SGA (SGA), to develop new models and to validate the algorithms.

METHODS

Existing models to predict height velocity (HV) for the first two and the fourth prepubertal years and during total pubertal growth (TPG) on GH were applied to SGA children from the KIGS (Pfizer International Growth Database)--1st year: N = 2340; 2nd year: N = 1358; 4th year: N = 182; TPG: N = 59. A new prediction model was developed for the 3rd prepubertal year based upon 317 children by means of the all-possible regression approach, using Mallow's C(p) criterion.

RESULTS

The comparison between the observed and predicted height velocity showed no significant difference when the existing prediction models were applied to new cohorts. A model for predicting HV during the 3rd year explained 33% of the variability with an error SD of 1.0 cm/year. The predictors were (in order of importance): HV previous year; chronological age; weight SDS; mid-parent height SDS and GH dose.

CONCLUSIONS

Models to predict growth to GH from prepubertal years to adult height are available for short children born SGA. The models utilize easily accessible predictors and are accurate. The overall explained variability in SGA is relatively low, due to the heterogeneity of the disorder. The models can be used to provide patients with a realistic expectation of treatment, and may help to identify compliance problems or other underlying causes of treatment failure.

Growth hormone treatment, final height, insulin-like growth factors, ghrelin, and adiponectin in four siblings with Seckel syndrome

OBJECTIVE

To report on the effect of growth hormone (GH) treatment on final height (FH) and to describe the insulin-like growth factor (IGF) system, ghrelin, and adiponectin (ADPN) in children with Seckel syndrome.

SUBJECTS AND RESULTS

Four severely growth-retarded Iraqi siblings (two girls and two boys) with Seckel syndrome were referred at ages 16.5, 14.4, 12.4, and 10.4 years. They were born at term, but their growth was retarded and birth weight ranged between 1 and 1.5 kg. The children were healthy and had a normal response to GH provocative test. Long-term GH treatment of the youngest brother and sister increased the FH by 7.2 and 3.4 cm, respectively, compared with their older brother and sister. At FH, body mass index standard deviation scores (BMISDS) ranged from -3.0 to -3.9. Serum levels of immunoreactive IGF-1, bioactive IGF-1, and IGF-binding protein 3 were all within normal to high range before GH treatment and increased after GH treatment. Fasting plasma ghrelin remained severely reduced. Despite low BMISDS, plasma ADPN was moderately reduced and showed an almost complete absence of the low-molecular-weight subform.

CONCLUSION

This is the first report on the effect of GH treatment on FH in children with Seckel syndrome. GH may have increased FH. In addition to growth defects and reduced BMISDS, patients with Seckel syndrome are characterized by low fasting ghrelin levels, low total ADPN, and near deficiency of the low-molecular-weight ADPN subform. The possible significance of the hormonal changes requires further investigations.

IGF-I and IGF Binding Protein-3 Generation Tests and Response to Growth Hormone in Children with Silver-Russell Syndrome

Objectives. To evaluate, in children with Silver-Russell Syndrome, the response to the IGF-I and IGFBP-3 generation test and compare results to the growth response after 6 months of rhGH. Methods. Eight children (6 males), with a mean age of 5.71 ± 2.48 years and height SDS of -3.88 ± 1.28 received rhGH for 6 months. IGF-I and IGFBP-3 were analyzed before and after 4 doses of rhGH. Results. The mean growth velocity (GV) before treatment was 5.28 ± 1.9 cm/year. GV increased after rhGH in five children to a mean GV of 10.3 ± 3.64 cm/year. Six children had normal basal IGF-I levels and two low levels. After 4 doses of rhGH, the IGF-I levels were normal in seven. There was no correlation between the growth response and the IGF-I generation test. Conclusions. Children with SRS have normal IGF-I generation test. There is no correlation between the generation test and the growth velocity after 6 months of rhGH.

Randomized GH trial with two different dosages in combination with a GnRH analogue in short small for gestational age children: effects on metabolic profile and serum GH, IGF1, and IGFBP3 levels

BACKGROUND

GnRH analogue (GnRHa) combined with GH treatment has been proposed to increase adult height. Effect on metabolic profile and GH, IGF1, and IGFBP3 levels in short small for gestational age (SGA) children is unknown.

OBJECTIVE

To assess fat mass and lean body mass SDS, percentage trunk fat, blood pressure (BP), insulin sensitivity (Si), beta-cell function (disposition index, DI), lipid profile, and GH, IGF1, and IGFBP3 levels during 2 years of combined treatment.

SUBJECTS

Forty-one pubertal short SGA children with a mean (+/-S.D.) age of 12.1 (+/-1.0) years.

DESIGN

Children received 3.75 mg of leuprolide acetate depot subcutaneously every 4 weeks, and they were randomly assigned to receive 1 mg (group A) or 2 mg (group B) of GH/m(2) per day.

RESULTS

Percentage trunk fat increased in both groups, but to a lower extent in group B. Lean body mass SDS increased only in group B. Changes in BP, Si, DI, and lipids were similar in both groups. Si significantly decreased, but DI remained unchanged. Lipids remained normal. GH and IGF1 levels were significantly higher in group B.

CONCLUSION

Our study is the first to report that 2 years of combined treatment with a GnRHa and either 1 or 2 mg GH/m(2) per day does not adversely affect body composition and metabolic profile of short SGA children who come under medical attention at the onset of puberty. There was a dose-dependent effect on fat mass SDS(height), percentage trunk fat, lean body mass SDS(height), and GH and IGF1 levels in favor of treatment with GnRHa and the higher GH dose of 2 mg/m(2) per day.

A case of Silver-Russell syndrome (SRS): multiple pituitary hormone deficiency, lack of H19 hypomethylation and favourable growth hormone (GH) treatment response

Hypomethylation of the imprinting control region 1 (ICR1) at the IGF2/H19 locus on 11p15 is linked to Silver-Russell syndrome (SRS) and/or hemihypertrophy. This SRS patient was born in term with weight of 3500 g (50 percentile) and length 48 cm (1 SD below the mean). He was first noticed at the age of 10 years for short stature (114.5 cm, -3.85 SD), relatively normal head circumference, a classic facial phenotype, hemihypertrophy (2.5 cm thinner left arm and leg in comparison to the right, asymmetric face), moderate clinodactyly and striking thinness (BMI of 15.3). At the age of 30, the body asymmetry ameliorated (1 cm thinner left arm and leg than the right), and BMI normalized (20.5 cm). Methylation analysis was performed by bisulphate treatment of DNA samples, radiolabelled PCR amplification, and digestion of the PCR products using restriction enzymes. The patient had normomethylation, and in addition hypopituitarism, with low levels of growth hormone (GH) (provocative testing before the start and after termination of GH treatment), thyroxin, TSH, FSH, LH and testosterone. The GH was given for six years, growth response was satisfactory and he reached an adult height of 166 cm. This is a first report of hypopituitarism in a patient with SRS without H19 hypomethylation. It seems that the lack of hypomethylation in this hypopituitary SRS patient is responsible, at least partly, for the favourable final adult height under GH treatment.

Impact of growth hormone therapy on adult height of children born small for gestational age

CONTEXT

Use of growth hormone (GH) therapy to promote growth in short children born small for gestational age (SGA) was recently approved in the United States and Europe, but there is still disagreement about the magnitude of effectiveness of GH.

OBJECTIVE

To determine the impact of GH therapy on adult height in short SGA children by a meta-analysis of randomized, controlled trials (RCTs).

METHODS

We performed a systematic review of controlled studies using as data sources the Cochrane Central Register of Controlled Trials, Medline, and the bibliographic references from all retrieved articles describing RCTs up to November 2008. A meta-analysis of all RCT studies conducted up to the achievement of adult height was performed. Inclusion criteria were birth weight and/or length below -2 SD score (SDS), initial height less than -2 SDS, and GH dose range of 33 to 67 microg/kg per day. Adult height SDS and overall height gain SDS were the primary outcome measures.

RESULTS

Four RCTs (391 children) met the inclusion criteria. The adult height of the GH-treated group significantly exceeded controls by 0.9 SDS. Mean height gain was 1.5 SDS in treated versus 0.25 SDS in untreated SGA subjects. No significant difference in adult height was observed between the 2 GH dose regimens.

CONCLUSIONS

GH therapy seems to be an effective approach to partially reduce the adult height deficit in short SGA children. However, the response to therapy is highly variable, and additional studies are needed to identify the responders.

Insulin sensitivity decreases in short children born small for gestational age treated with growth hormone

OBJECTIVES

To evaluate insulin sensitivity in short children born small for gestational age (SGA) treated with growth hormone (GH), and to study the relationship between growth response and insulin levels.

STUDY DESIGN

In 29 children (16 female, 13 male) who were short and SGA, an oral glucose tolerance test was performed before (mean age, 8.8 years; range, 4.5-14.3 years) and after 1 year of GH treatment (33 microg/kg/day). Insulin sensitivity was calculated with the homeostasis model assessment (HOMA) and the insulin sensitivity index (ISI) of Matsuda.

RESULTS

The mean height increased from -3.1 to -2.4 SD. Insulin resistance (ISI<5) was seen in 17.2% of children before and in 48.3% (mainly pubertal) children after GH treatment. Insulin sensitivity decreased significantly: ISI fell from 12.2 to 6.1 (P= .02) and HOMA increased from 1.2 to 2.2 (P= .001). Glucose and HbA1c levels did not change significantly. ISI after 1 year did not correlate with height gain, but it did correlate with age (r= -0.469; P= .01) and body mass index (r= -0.52; P= .004).

CONCLUSIONS

Insulin sensitivity is impaired in some children who are SGA already at baseline and decreases with GH treatment in most of them. Children close to puberty and children who are less underweight have the highest risk to become insulin resistant.

Growth hormone treatment for short stature in children born small for gestational age

Children born small for gestational age (SGA) who do not show catch-up in the first 2 years generally remain short for life. Although the majority of children born SGA are not growth hormone (GH) deficient, GH treatment is known to improve average growth in these children.Early studies using GH in children born SGA demonstrated increased height velocity, but these effects tended to be short-term with effects decreasing when GH treatment stopped. With refined GH regimens, significant effects on height have been shown, with gains of approximately 1 standard deviation score after 2 years. Studies have also shown that long-term continuous GH therapy can significantly increase final height to within the normal range. GH treatment of children born SGA does not appear to unduly affect bone age or pubertal development. Growth prediction models have been used to identify various factors involved in the response to GH therapy with age at start, treatment duration, and GH dose showing strong effects. Genetic factors such as the exon 3 deletion of the GH receptor may contribute to short stature of children born SGA and may also be involved in the responsiveness to GH treatment, but there remain other unknown genetic and/or environmental factors. No unexpected safety concerns have arisen in GH therapy trials. In particular, no long-term adverse effects have been seen for glucose metabolism, and positive effects have been shown for lipid profiles and blood pressure.GH treatment in short children born SGA has shown a beneficial, growth-promoting effect in both the short-and long-term, and has become a recognized indication in both the US and Europe. Further studies on individualized treatment regimens and long-term safety are ongoing.

Safety and efficacy of growth hormone treatment in small for gestational age children

PURPOSE OF REVIEW

Approximately 100,000 infants are born small for gestational age (birth weight <2 standard deviation) annually in the US alone. Because of catch-up growth, 10-20% of all children born small for gestational age will be eligible for growth hormone therapy. Growth hormone has been approved by the Food and Drug Administration in 2003 and by the European Agency for the Evaluation of Medical Products though at different enrollment and treatment criteria. Benefits and risks of growth hormone therapy for small for gestational age children are the purpose of the present review.

RECENT FINDINGS

Mean height increased by as much as two standard deviation over 3 years of treatment in infants born small for gestational age. Rapid catch-up growth is desirable and will only be achieved with higher growth hormone doses (0.48 mg/kg/week) Treatment should be continuous and not interrupted. The safety profile of growth hormone treatment is excellent. Transient elevation of insulin levels returned to near normal after growth hormone treatment was discontinued.

SUMMARY

Growth hormone treatment in small for gestational age children has been found to be well tolerated and is an important advance in the treatment of short stature in pediatrics. Treatment of short prematurely born infants with growth hormone may offer similar efficacy and safety as growth hormone treatment in small for gestational age infants.

[Growth hormone therapy for short children born small for gestational age]

Approximately 10% of all children born small for gestational age (SGA) fail to achieve sufficient catch-up growth and remain with short stature throughout childhood and adult life. Abnormalities of the GH/IGF-1 axis are not always identified. Several studies have demonstrated that GH is an effective and well-tolerated therapy and most children will reach a normal adult height. In this review, it can be seen the encouraging results of GH treatment in growth-retarded children born SGA highlighting the benefits of early treatment.

Individualization of growth hormone therapy

Short children born small for gestational age account for 20% of patients with short stature. These children should be investigated individually to identify treatable causes of their short stature and any associated neurodevelopmental problems. Randomized controlled growth hormone therapy trials demonstrate growth acceleration in childhood and improved adult height. The individualization of therapy is increasingly possible with insight from the available prediction models. These identify the main modifiable factors such as dose of growth hormone and age at the start of therapy. Non-modifiable factors including target height standard deviation score (SDS), weight SDS at the start of therapy, and first year response to therapy also play a significant role.

Growth hormone therapy for short children born small for gestational age

Children born small for gestational age may demonstrate continued growth retardation, resulting in persistent short stature. In the majority of the cases, this is linked with abnormal growth hormone secretion and also abnormal insulin-like growth factor levels. This review discusses the treatment of such children with recombinant human growth hormone. It illustrates the importance of starting therapy early, the dose-dependent response, and the advantages of continuous therapy and describes safety considerations.

Small for gestational age: short stature and beyond

Depending on the definitions used, up to 10% of all live-born neonates are small for gestational age (SGA). Although the vast majority of these children show catch-up growth by 2 yr of age, one in 10 does not. It is increasingly recognized that those who are born SGA are at risk of developing metabolic disease later in life. Reduced fetal growth has been shown to be associated with an increased risk of insulin resistance, obesity, cardiovascular disease, and type 2 diabetes mellitus. The majority of pathology is seen in adults who show spontaneous catch-up growth as children. There is evidence to suggest that some of the metabolic consequences of intrauterine growth retardation in children born SGA can be mitigated by ensuring early appropriate catch-up growth, while avoiding excessive weight gain. Implicitly, this argument questions current infant formula feeding practices. The risk is less clear for individuals who do not show catch-up growth and who are treated with GH for short stature. Recent data, however, suggest that long-term treatment with GH does not increase the risk of type 2 diabetes mellitus and the metabolic syndrome in young adults born SGA.

Growth hormone treatment strategy for short children born small for gestational age

Several studies performed in the last 15 years have shown that growth hormone (GH) induces a profound catch-up in height in short children born small for gestational age (SGA). We know from more recent studies that final height can be normalized through GH treatment. In Europe, GH is now a recognized indication, enabling treatment of short children born SGA. Treatment is given to the most severe growth-retarded children after the age of 4 years. A dose of 0.035 mg/kg per day is recommended. However, in our opinion a higher dose would be more efficient in very short children, especially if they are treated later in childhood.

Should recombinant human growth hormone therapy be used in short small for gestational age children?

Short small for gestational age (SGA) children represent 20% of all children with short stature and therefore constitute a significant portion of the caseload in a growth clinic. The recent approval of recombinant human growth hormone (GH) for the treatment of short stature in SGA children by the European Union's Committee on Proprietary Medicinal Products offers a new licensed therapeutic option. This article examines the role of GH therapy in short SGA children with particular reference to selection of patients, effectiveness, safety, and its potential metabolic implications.

Growth and growth hormone in children born small for gestational age

At present, there are no uniform definitions for terms such as "small for gestational age" (SGA) and "catch-up growth" that can be used when evaluating children who are born small. Data suggest that growth hormone (GH) therapy can play a role in helping children born SGA achieve adequate height. For therapy to be successful, however, precise terminology must be defined and standardized, surveillance and identification of potential candidates must be performed, and treatment plans must be tailored to the unique needs of each patient. This manuscript focuses on each of these issues, and also identifies additional concerns that must be addressed as a consequence.

GH treatment and its effect on bone mineral density, bone maturation and growth in short children born small for gestational age: 3-year results of a randomized, controlled GH trial

BACKGROUND

To investigate in a group of short children born small for gestational age (SGA), the effects of 3 years of GH treatment vs. no treatment on bone age (BA), height and bone mineral density (BMD). Also, to evaluate the influence of the severity of growth retardation at start and the GH dose on the gain in height.

PATIENTS AND METHODS

The study design was an open-labelled, controlled multicentre GH study for 3 years. Non-GH-deficient (GHD) children (n = 87) were randomized to either a GH group (n = 61) or an untreated control group (n = 26). In addition, 12 SGA children had GHD (GHD group) and were treated in parallel. Both the GH and the GHD group were treated with a GH dose of 33 microg/kg/day. BMD was evaluated using dual energy X-ray absorptiometry (DEXA). In addition, data of our first GH trial in which short SGA children were treated with a GH dose of 66 microg/kg/day (n = 24) were used for comparison of height gain.

RESULTS

In contrast to the control group, the GH group showed a significant increase in height (P < 0.001), as did the parallel GHD group. Bone maturation [delta bone age (BA)/delta calendar age (CA)] increased significantly during the first 2 years of GH treatment but slowed-down thereafter. The 3-year deltaBA/deltaCA ratio correlated significantly with the gain in height (r = 0.6, P < 0.001). At start, mean BMD SDS and mean BMAD SDS were significantly lower than zero. During GH treatment both increased impressively (P < 0.001). The gain in height of children with severe short stature at start (< or = -3.00 SDS), did not differ between those receiving either a GH dose of 33 or 66 microg/kg/day.

CONCLUSION

Three years of GH treatment in short children born SGA results in a normalization of height during childhood. Also, bone maturation increased proportionately to the height gain. At start, mean values of BMD and BMAD were significantly reduced but normalized during GH treatment. We did not find an indication to treat very short SGA children (H SDS < or = -3.00) with a higher GH dose. We rather suggest to start GH treatment at an early age in order to achieve a normal height before puberty starts.

International Small for Gestational Age Advisory Board consensus development conference statement: management of short children born small for gestational age, April 24-October 1, 2001

OBJECTIVE

To provide pediatric endocrinologists, general pediatricians, neonatologists, and primary care physicians with recommendations for the management of short children born small for gestational age (SGA).

METHODS

A 13-member independent panel of pediatric endocrinologists was convened to discuss relevant issues with respect to definition, diagnosis, and clinical management of short children born SGA. Panel members convened over a series of 3 meetings to thoroughly review, discuss, and come to consensus on the identification and treatment of short children who are born SGA.

CONCLUSIONS

SGA is defined as birth weight and/or length at least 2 standard deviations (SDs) below the mean for gestational age (<or=-2 SD). Accurate gestational dating and measurement of birth weight and length are crucial for identifying children who are born SGA. Comprehensive pregnancy, perinatal, and immediate postnatal data may help to confirm the diagnosis. Maternal, placental, and fetal causes of SGA should be sought, although the cause is often not clear. Most children who are SGA experience catch-up growth and achieve a height >2 SD below the mean; this catch-up process is usually completed by the time they are 2 years of age. A child who is SGA and older than 3 years and has persistent short stature (ie, remaining at least 2 SD below the mean for chronologic age) is not likely to catch up and should be referred to a pediatrician who has expertise in endocrinology. Bone age is not a reliable predictor of height potential in children who are SGA. Nevertheless, a standard evaluation for short stature should be performed. A diagnosis of SGA does not exclude growth hormone (GH) deficiency, and GH assessment should be performed if there is clinical suspicion or biochemical evidence of GH deficiency. At baseline, insulin-like growth factor-I, insulin-like growth factor binding protein-3, fasting insulin, glucose, and lipid levels as well as blood pressure should be measured, and all aspects of SGA-not just stature-should be addressed with parents. The objectives of GH therapy in short children who are SGA are catch-up growth in early childhood, maintenance of normal growth in childhood, and achievement of normal adult height. GH therapy is effective and safe in short children who are born SGA and should be considered in those older than 2 to 3 years. There is long-term experience of improved growth using a dosage range from 0.24 to 0.48 mg/kg/wk. Higher GH doses (0.48 mg/kg/wk [0.2 IU/kg/d]) are more effective for the short term. Whether the higher GH dose is more efficacious than the lower dose in terms of adult height results is not yet known. Only adult height results of randomized dose-response studies will give a definite answer. Monitoring is necessary to ensure safety of medication. Children should be monitored for changes in glucose homeostasis, lipids, and blood pressure during therapy. The frequency and intensity of monitoring will vary depending on risk factors such as family history, obesity, and puberty.

The Russell-Silver syndrome: a case report and brief review of the literature

The Russell-Silver syndrome's phenotypic features consist of musculoskeletal abnormalities, genitourinary malformations, craniofacial dysmorphy and cutaneous dyschromia, which is usually reported as café au lait spots. We present the first instances of a large, unilateral, achromic patch as an additional cutaneous manifestation of the Russell-Silver syndrome.

Adrenarche, pubertal development, age at menarche and final height of full-term, born small for gestational age (SGA) girls

Children born small for gestational age (SGA) may present advanced bone maturation in childhood and reduced final height. The objectives of the study were to evaluate adrenarche, pubertal development, age at menarche and final height in full-term born-SGA girls. Twenty-four girls (12 born-SGA and 12 matched controls) were evaluated at 6-7.5 years of age for clinical signs of puberty and dehydroepiandrosterone sulfate (DHEAS) levels, as a marker of adrenarche. Thirty-eight girls (19 born-SGA and 19 matched controls) were evaluated at 17.5-18.5 years of age to assess final height, sexual maturation and age at menarche. SGA girls had a mean final height (160.1 cm vs 165.8 cm, p < 0.01) and mean weight (52.1 kg vs 56.5 kg, p < 0.05) significantly lower than controls. Controls had a mean final height significantly higher than their mean target height. Sexual maturation was at stage 5 of Tanner's staging in SGA girls and control subjects. SGA girls had a slightly anticipated puberty (9.9 vs 10.4 years for initial breast development) and a lower age at menarche (11.9 vs 12.3 years). At 6-7.5 years of age, SGA females and controls did not show any difference for clinical signs of puberty; however, DHEAS levels (0.75 + 0.18 microgram/ml vs 0.57 + 0.22 microgram/ml, p < 0.05) were significantly higher in SGA girls than in control subjects. We concluded that full-term born-SGA females have impaired final height and weight in adolescence but substantially normal sexual maturation and age at menarche. Increased DHEAS levels before puberty in born-SGA girls may predispose to increased bone maturation in childhood with a reduced final height. In our population a progressive increment in final stature is evident.

Growth hormone treatment in short children with intrauterine growth retardation

The aim of this prospective controlled study was to assess the effect of rhGH in short prepubertal children with intrauterine growth retardation and normal growth hormone status. Twenty-six children were randomized into treatment (12F, 4M) and control (6F, 4M) groups. Mean ages were 5.3 (1.3) yr and 4.3 (1.7) yr, respectively. rhGH (Genotropin) was used at a dose of 0.2 IU/kg/day as daily s.c. injections for two years. In the treated group, mean height SDS increased from -3.0 (0.5) to -1.9 (0.7) and height velocity SDS showed a significant increase from -1.3 (2.0) to 3.7 (1.8) in the first year (p < 0.001) and 1.6 (1.8) (p < 0.01) in the second year of treatment. In the controls, height SDS, initially -2.7 (1.4), and height velocity SDS, initially -0.9 (1.1), remained essentially the same during two years of follow-up. Height SDS for bone age changed by 0.6 in the treated group and 0.4 in the control group. Target height SDS--initial height SDS in the treated group improved by 1.1 SD but declined in the control group. IGF-I levels increased from 9.5 (4.2) nmol/l (72 [31.8] ng/ml) to 32.5 (27.0) nmol/l (244.4 [202.8] ng/ml) (p = 0.004) in the treated group while no change was observed in the controls. No adverse effects were encountered during rhGH therapy. It was concluded that rhGH treatment induces a significant increase in growth velocity in the short term. This outcome, as opposed to the unchanged indices in the control group over the same period, may be indicative of an improved height prognosis in short children born with intrauterine growth retardation treated with rhGH.

Fetal size to final height in Hong Kong Chinese children

OBJECTIVES

It has been known that size at birth is important for postnatal growth and final height. However, there are few data in the literature on the difference in height growth patterns from fetal size to final height between less privileged and more privileged populations. The aim of this study was to describe the important features in height growth from birth to maturity in an underprivileged Hong Kong Chinese cohort in comparison to a more privileged Swedish cohort.

METHODS

The longitudinal height growth data from birth to maturity in full-term healthy Hong Kong Chinese children (n=132) who were born in 1967 were analyzed, and compared with those for Swedish children who were born in 1973-75 (n=3650).

RESULTS

Children with longer birth length achieved taller adult stature with respect to their target height. The mean final height retained the same order as that of the mean length at birth for various birth length groups. All children in the Hong Kong Chinese series showed catch-down height growth during the first 2 years of life, in contrast to the catch-up in smaller babies and catch-down in larger babies for the Swedish series. The growth deficit for the Hong Kong Chinese was -0.9 SDS at birth, -1.8 SDS at 2.0 years of age, -2.1 SDS at 8 years of age, and -1.7 SDS at final height.

CONCLUSIONS

Fetal size is important for postnatal growth and attained final height with respect to a child's familial genetic potential in stature, not only for privileged populations, but also for underprivileged populations. However, children in underprivileged populations experience a persistent increasing growth deficit during infancy and childhood. Special attention should be given to monitor their growth status in early years and to institute appropriate intervention programs.

Predicting the response to recombinant human growth hormone in Turner syndrome: KIGS models. KIGS International Board. Kabi International Growth Study

A mathematical model for predicting the growth response in patients with Turner syndrome who received growth hormone (GH) therapy was developed by analysing data from KIGS, the Pharmacia & Upjohn International Growth Database. A model for year 1 of GH therapy explained 46% of the variability of the growth response, with GH dose being the most important of the predictors of height velocity. In years 2-4 of therapy, height velocity during the previous year was the most important predictor, suggesting that an individual's initial response to GH may determine the height outcome of treatment. Additional predictors of height velocity in years 1-4 of GH therapy included age (negative), weight SDS and additional treatment with oxandrolone. The predictions in all 4 years were highly accurate, as indicated by the low error SDs. However, relatively low predictive power (R) during years 2-4 of treatment suggests the models are missing other parameters that would explain more of the variability of the growth response. These growth prediction models could help clinicians to design individualized treatment regimens, provide realistic expectations of therapy outcomes, and adjust treatment on the basis of detected differences between observed and predicted height velocities.

Length and body mass index at birth and target height influences on patterns of postnatal growth in children born small for gestational age

OBJECTIVE

Previous growth studies on children born small for gestational age (SGA) indicate that birth length, weight, and target height are important predictors for postnatal catch-up growth in SGA. Their influences on different phases of catch-up growth are still not described. The aim of this study was to clarify the influences of target height, length, and nutritional status at birth on different phases of postnatal catch-up growth (infancy, childhood, puberty) in SGA and the long-term consequences.

METHODS

Data were obtained from a longitudinal population-based growth study on Swedish children (N = 2815). Primary outcome measurements include heights, the changes in height standard deviation scores (SDS) during various phases of growth and relative risk for adult shortness.

RESULTS

The difference in final height in children born SGA was attributable to their difference in target height and the magnitude of catch-up growth during the first 6 months of life, rather than the difference in length or body mass index (BMI) at birth. Length at birth showed negative influence on catch-up growth during infancy (0 to 2 years of age), but no significant influence thereafter. The BMI or weight for length SDS at birth showed no significant influence on catch-up growth during any growth phase. Target height showed positive influence on catch-up growth from the onset of childhood. Neither target height nor length and BMI at birth showed any significant influence on catch-up growth during puberty. The magnitude of catch-up growth during infancy, especially the first 6 months of life, is most critical in decreasing risk at adult shortness. We confirmed that the SGA group had a sevenfold greater risk for adult shortness than the non-SGA group (relative risk = 7.31; 95% confidence interval: 3.96-13.52). However, approximately 40% of children who were below -2 in height SDS at 2 years of age remained short at final height in both SGA and non-SGA groups. The mean height SDS of children born SGA increased by 1.65 from birth to final height, but the length deficit in centimeters at birth (-5.4 cm) persisted into adulthood (-5.9 cm).

CONCLUSIONS

BMI at birth is not related to postnatal catch-up growth in infants born SGA, but birth length and target height are important. The genetic influence on catch-up growth appears to start from the onset of childhood. Being born short or becoming short during the first 2 years of life is similar in terms of risk for adult short stature.

Target height as predicted by parental heights in a population-based study

The corrected midparental height method was introduced by Tanner in 1970 (Tanner method) and is commonly used to estimate target height in children to evaluate the effectiveness of growth-promoting therapies. It has not been established if the equation used to compute target height should be the same for children with short, normal, or tall parents. In this study, we examined the predicted target height values by parental heights in a large population-based study (n = 2402). A simple linear function of midparental height (x) was proposed to estimate target height (y): y = 45.99 + 0.78x (boys), y = 37.85+0.75x (girls), with a 95% predicted interval of about +/-10 cm. The prediction model was similar for boys and girls in SD scores (SDS), and was not affected by assortative mating or difference in parental heights. The model may underestimate the potential stature by about 2 cm for children with midparental height below -2 SDS, or 163 cm. In comparison, the Tanner method may lead to a 6-cm error in underestimating target height for these children. The function would be a better choice than the Tanner method for estimating target height in the clinical evaluation of growth promotion treatments because it is common that short children also have short parents. Children with very short parents will usually be much taller than their parents in adult stature, and we believe that a different function should be developed. The results support the proposed nondominant, non-sex-linked, polygenic inheritance in stature. The estimated heritability values were 0.75-0.78 in cm or 0.55-0.60 in SDS.