Birth weight affects final height in patients treated for growth hormone deficiency

Different long-term response to growth hormone therapy in small- versus appropriate-for-gestational-age children with growth hormone deficiency

BACKGROUND/AIMS

The role of birth weight on growth hormone (GH) therapy response in GH-deficient (GHD) children has not been fully elucidated. Therefore, we examined the growth of 23 small-for-gestational-age GHD children (SGA-GHD, 11 females and 12 males), 26 appropriate-for-gestational-age GHD children (AGA-GHD, 11 females and 15 males) during the first 5 years of GH therapy and that of 22 non-GH-treated SGA children (12 females and 10 males).

METHODS

We collected height and height velocity measurements yearly.

RESULTS

In AGA-GHD children, height was always greater than in the SGA groups and significantly increased from the fourth year of treatment. Height velocity was higher (SGA-GHD: 1.72 ± 0.30 standard deviation score, SDS, AGA-GHD: 2.67 ± 0.21 SDS; p = 0.039) in AGA-GHD children during the first year of treatment. The AGA-GHD group showed the highest percentage (52.4%) of subjects surpassing mid-parental height and the greatest height gain after 5 years of follow-up.

CONCLUSION

Our results show that birth size is an important factor affecting the response to GH therapy in GHD children during the first 5 years of treatment. The paediatric endocrinologist should be aware of this factor when planning the management of GHD children born SGA.

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.

Final height in children with idiopathic growth hormone deficiency treated with a fixed dose of recombinant growth hormone

There is no consensus regarding the optimal dosing of recombinant human growth hormone (rhGH) for children with growth hormone deficiency (GHD). Our objective was to evaluate the final adult height (FAH) in children with idiopathic GHD treated with a fixed rhGH dose of 0.18 mg/kg/week. We reviewed all charts of patients with idiopathic GHD treated with rhGH since 1985 who reached FAH. Ninety-six patients were treated for an average of 5.4 years. The mean age was 11.9 years, the mean height -2.87 standard deviation score (SDS) and the mean FAH was -1.04 SDS. Females had a lower predicted adult height than males at the initiation of therapy (-2.0 vs. -1.01 SDS; p = 0.0087) but a higher FAH - predicted adult height (1.08 vs. 0.04 SDS; p = 0.0026). In multiple regression analysis, the FAH SDS was positively related to the midparental height SDS, the height SDS at GH initiation and growth velocity during the first year of therapy, and negatively correlated with peak GH and bone age at initiation (r(2) = 0.51; p < 0.005). Treatment of children with idiopathic GHD with a fixed dose of 0.18 mg/kg/week rhGH is sufficient to reach FAH within 2 SDS of the normal population range (84%) with an average FAH within -0.5 SDS of midparental height.

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.

Comparison of final height in monozygotic twins, one with idiopathic and isolated growth hormone deficiency treated with low dose of growth hormone

OBJECTIVE

We report final heights in a pair of monozygotic twins, one unaffected and the other affected with idiopathic and isolated growth hormone (GH) deficiency treated with human GH, and discuss the effect of GH dosage on the attainment of the genetic height potential in GH deficiency.

PATIENTS

Male monozygotic twins were born at 35 weeks of gestation; birth weights were 1,876 g in the unaffected and 1,510 g in the affected twin. At 4.9 years of age, the affected twin was studied for short stature (-3.38 SD) and was diagnosed as having idiopathic and isolated GH deficiency, whereas the unaffected twin was normal in height (+/- 0 SD). GH treatment was started at the age of 5.7 years and continued throughout childhood and adolescence. The average dose of GH administered during the treatment period was 0.35 IU (0.12 mg)/kg/week. The affected twin appeared to grow normally without other hormone replacement and achieved a final height of 165.6 cm (-0.86 SD) compared with that of 166.4 cm (-0.71 SD) in the unaffected twin at 17.5 years of age.

CONCLUSION

Our results indicate that a relatively low dose of GH treatment started at an early age may preserve genetic height potential in patients with isolated GH deficiency.

Final height of short subjects of low birth weight with and without growth hormone treatment

AIM

To compare final height in two groups of low birth weight children examined for short stature: the first group untreated because of normal growth hormone (GH) secretion, the second treated with human growth hormone (hGH) because of abnormal secretion.

METHODS

A total of 49 subjects born at term of birth weight below the 10th centile were consecutively examined for idiopathic short stature. The first group of subjects (n = 20) with normal GH peaks after pharmacological tests (>8 microg/l) spontaneously reached final height. The second group (n = 29) with abnormal secretion were treated with hGH (20 U/m(2)/week) for 36-84 months. At diagnosis the two groups were of similar height for chronological age and bone age, and had similar target height.

RESULTS

In both groups final height was significantly lower than target height (-0.65 (SEM 0.20) in untreated cases, -0.61 (0.18) in treated cases). Fewer than one third of subjects had a final height above target height. Final height data of untreated and treated cases were not different. In the treated group the best results were obtained by those subjects who improved their height for bone age after three years of therapy.

CONCLUSIONS

Our subjects with birth weight below the 10th centile remained as short adults with final height below target height. Treatment with hGH 20 U/m(2)/week in those diagnosed as deficient was not effective, with final results overlapping those of untreated subjects.

Early puberty: rapid progression and reduced final height in girls with low birth weight

OBJECTIVE

To assess whether, in girls with early onset of puberty, low birth weight is a risk factor for rapid progression to menarche and for short adult stature.

DESIGN

Longitudinal clinical assessment of 54 Catalan (Northern Spanish) girls followed from early onset of puberty (onset of breast development between 8.0 and 9.0 years of age) to final height. The timing of menarche and the final height were analyzed a posteriori according to birth weight, the cutoff level between normal and low birth weight subgroups being -1.5 standard deviation (SD; approximately 2.7 kg at term birth).

RESULTS

Normal and low birth weight girls had similar target heights and characteristics at diagnosis of early puberty. However, menarche occurred on average 1.6 years earlier in low versus normal birth weight girls (11.3 +/-.3 years vs 12.9 +/-.2 years), and final height was >5 cm shorter in low birth weight girls (parental adjusted height SD: -.6 +/-.2 cm vs.3 +/-.2 cm).

CONCLUSION

The timing of menarche and the level of final height in Catalan girls with early onset of puberty was found to depend on prenatal growth. Girls with normal birth weight tend to progress slowly through puberty with a normal timing of menarche and normal final height. In contrast, girls with low birth weight tend to progress relatively rapidly to an early menarche and to a reduced final height. If these findings are confirmed in other ethnic and/or larger groups, then a subgroup has been identified that will most likely benefit from any therapeutic intervention aiming at a delay of pubertal development and/or an increase of final height.