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

Effect of growth hormone treatment on children with idiopathic short stature (ISS), idiopathic growth hormone deficiency (IGHD), small for gestational age (SGA) and Turner syndrome (TS) in a tertiary care center

OBJECTIVES

To assess the long-term effect of growth hormone (GH) therapy in a large cohort of short children with different etiologies.

PATIENTS AND METHODS

We evaluated retrospectively the anthropometric data of 252 short children [height SDS <-2: 154 children with growth hormone deficiency (GHD), 63 with idiopathic short stature (ISS), 26 with SGA, and 9 with Turner syndrome (TS)] who were treated, in our center, with GH between 1-2007 and 1-2018. Before and during recombinamt growth-hormone (recGH) treatment, auxological parameters including height (Ht), weight (Wt), Ht - Z score (HtSDS), body mass index (BMI) and BMISDS were recorded every 6 months; bone age (BA) was assessed every 12 months.

RESULTS

At the end of first year of rhGH therapy and after an average of 3 years treatment all groups of short children had significant increase in HtSDS, which was higher in GHD compared to other groups. Children with GHD, SGA, ISS and TS increased their HtSDS by an average of 2.2, 1.46, 0.6 and 0.99 SD, respectively at the end of follow up period (for all groups, p: <0.001). The bone age/chronological age (BA/CA) ratio did not differ significantly among ISS, GHD and SGA groups after GH therapy. The HtSDS gain was higher in children with GHD compared to other ISS, SGA and TS groups (p:< 0.01; p: 0.015 and p: 0.029, respectively).  HtSDS improvement occurred during the first 3 years of rhGH therapy. The BMISDS increased significantly in children with GHD, after 3 years of rhGH therapy (p: < 0.001). After rhGH treatment, the BMISDS decreased significantly in children with ISS and SGA (p: < 0.01 and < 0.001, respectively) but did not change in children with TS (p: 0.199).

CONCLUSIONS

Children with GHD, SGA, ISS and TS exhibited significant increases in HtSDS when treated with rhGH for 3 years. The HtSDS gain was higher in children with GHD compared to other groups.

Risk factors for absence of catch-up growth in small for gestational age very low-birthweight infants

BACKGROUND

Many small for gestational age (SGA) infants have catch-up growth during the first 2 years of life, but approximately 10% have no catch-up growth, and short stature continues into adulthood. Identification of risk factors for absence of catch-up growth at an early age may be useful for earlier diagnosis and earlier treatment.

METHODS

This was a retrospective multicenter study. The subjects were SGA infants with very low-birthweight (VLBW), who were followed up until the age of 3 years. The risk factors for absence of catch-up growth were identified on statistical analysis.

RESULTS

Of the 217 SGA infants in this study, 181 were in the catch-up group and 36 were in the no catch-up group. The catch-up rate was 83%. On multivariate analysis adjusted for gestational age, birthweight, birth height, and birth head circumference, multipara, Z and ΔZ scores of length at 12 months of corrected age, and the Z score of height at 24 months of corrected age were risk factors for lack of catch-up at 3 years.

CONCLUSIONS

The length Z and ΔZ scores at 12 months of corrected age may be useful for an earlier diagnosis and earlier initiation of growth hormone treatment in VLBW infants.

A prospective study about physical growth of children from birth to 2 years old born full-term small-for-gestational-age

AIM

To evaluate the growth trend of children from birth to 2 years old born full-term small-for-gestational-age (SGA) in Chengdu, China.

METHODS

Full-term SGA infants were prospectively followed from birth to 2 years of age. The weight, length and head circumference were monitored at 3, 6, 12, 18 and 24 months. Catch-up growth and growth velocity were measured by using standardised z-score and Δz-score. Growth deviation was analysed.

RESULTS

A total of 850 full-term SGA infants were involved in our study. There were no significant differences in weight or length at birth between male and female infants. Full catch-up growth was seen in 95.85% of SGA infants within 2 years of life, with no gender differences. The z-score and Δz-score for weight at 3 months were less than those at other ages (P < 0.05). The z-score and Δz-score for length at 3 and 6 months were less than those at other ages (P < 0.05). Smaller z-score for head circumference was seen at 3 and 6 months (P < 0.05). The z-score for body mass index at 6 months was the largest over the period of follow-up. The total prevalence of being overweight or obese fluctuated around 10% at different follow-up stages. Males had a faster growth velocity for length at 12 months compared to females (P < 0.05). The proportion of those who were underweight, of short stature or had a head circumference z-score < -2 significantly decreased between 3 and 6 months. At 24 months, there was an increase in z-score of 0.67 standard deviation for both weight and length in most full-term SGA infants, and the proportion of underweight and short stature was 2.97 and 2.67%, respectively.

CONCLUSIONS

Most full-term SGA infants undergo catch-up growth during the first year of life. Regardless of gender, the catch-up velocity for weight exceeded that for length at each visit. Additional follow-up studies are needed to determine long-term growth outcomes for full-term SGAs.

A 2-year multicentre, open-label, randomized, controlled study of growth hormone (Genotropin®) treatment in very young children born small for gestational age: Early Growth and Neurodevelopment (EGN) Study

OBJECTIVE

In Europe, growth hormone (GH) treatment for children born small for gestational age (SGA) can only be initiated after 4 years of age. However, younger age at treatment initiation is a predictor of favourable response. To assess the effect of GH treatment on early growth and cognitive functioning in very young (<30 months), short-stature children born SGA.

DESIGN

A 2-year, randomized controlled, multicentre study (NCT00627523; EGN study), in which patients received either GH treatment or no treatment for 24 months.

PATIENTS

Children aged 19-29 months diagnosed as SGA at birth, and for whom sufficient early growth data were available, were eligible. Patients were randomized (1:1) to GH treatment (Genotropin®, Pfizer Inc.) at a dose of 0·035 mg/kg/day by subcutaneous injection, or no treatment.

MEASUREMENTS

The primary objective was to assess the change from baseline in height standard deviation score (SDS) after 24 months of GH treatment.

RESULTS

Change from baseline in height SDS was significantly greater in the GH treatment vs control group at both month 12 (1·03 vs 0·14) and month 24 (1·63 vs 0·43; both P < 0·001). Growth velocity SDS was significantly higher in the GH treatment vs control group at 12 months (P < 0·001), but not at 24 months. There was no significant difference in mental or psychomotor development indices between the two groups.

CONCLUSIONS

GH treatment for 24 months in very young short-stature children born SGA resulted in a significant increase in height SDS compared with no treatment.

Modeling height for children born small for gestational age treated with growth hormone

The analysis of growth curves of children can be done on either the original scale or in standard deviation scores. The first approach is found in many statistical textbooks, while the second approach is common in endocrinology, for instance in the evaluation of the effect of growth hormone in children that are born small for gestational age that remain small later in childhood. We illustrate here that the second approach may involve more complex modeling and hence a worse model fit.

Predictors of growth in children based on 2007 Korean National Growth Charts

BACKGROUND

Postnatal growth patterns in children are associated with various factors within the birth and infancy periods. The aim of the present study was to examine the correlation between growth patterns and parameters including gestational age (GA), birthweight (BW), sex, and feeding method in the records of 61,631 children aged 6-72 months.

METHODS

The data were obtained from the 2007 Korean National Growth Charts provided by the Korean Centers for Disease Control. Data were analyzed using descriptive statistics, Pearson's correlation, and multiple linear regression.

RESULTS

BW and sex were highly correlated with weight and height by 72 months (P < 0.01), with BW being the primary predictor (P < 0.001). Sex was the second predictor of weight and height in children by 66 months (P < 0.01). Feeding method was the predictor of weight in children aged 12-48 months and 60 months (P < 0.05), and was also influential in the height of children by 48 months (P < 0.05). GA was the predictor of weight at 12 months and from 30 to 42 months (P < 0.05).

CONCLUSION

GA, BW, sex and feeding method were the predictors of weight and height among children at different times. Therefore, the present population-based study strengthens the consideration of these factors for routine monitoring of growth patterns in Korean children.

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.

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.

Prediction model for adult height of small for gestational age children at the start of growth hormone treatment

CONTEXT

GH treatment is approved for short children born small for gestational age (SGA). The optimal dose is not yet established.

OBJECTIVE

Our objective was to develop a model for prediction of height at the onset of puberty and of adult height (AH).

DESIGN AND SETTING

Two GH studies were performed in short SGA children.

PATIENTS/INTERVENTION

A total of 150 SGA children with height sd scores (SDS) less than -2, age 3 yr or older, no signs of catch-up growth, available height at the onset of puberty, and at least 1 yr of GH treatment before the onset of puberty were studied. In one study, patients were randomly assigned to either 0.033 or 0.067 mg/kg x d; in the other study all received 0.033 mg/kg x d. In 71 children, AH was reached.

MAIN OUTCOME MEASURES

Height SDS at the onset of puberty and AH SDS were calculated.

RESULTS

Determinants positively related to height SDS at the onset of puberty were: height SDS at the start; target height SDS; and GH dose, whereas age at the start and female gender were negatively related. Positively related to AH SDS were: height SDS and chronological age--bone age at the start; target height SDS; and GH dose, whereas serum IGF binding protein (IGFBP)-3 SDS at the start was negatively related. There was a significant interaction between GH dose and IGFBP-3 SDS, indicating a smaller GH dose effect for higher levels of IGFBP-3. The final model explained 57% of the variance in height SDS at the onset of puberty and 41% of AH SDS.

CONCLUSIONS

The prediction model for height SDS at the onset of puberty and AH SDS of short SGA children treated with GH provides useful information about the expected long-term growth. Because GH dosage is one of the determinants, the model aids in determining the optimal GH dose for each child.

Longitudinal follow-up of height up to five years of age in infants born preterm small for gestational age; comparison to full-term small for gestational age infants

OBJECTIVE

This aims to conduct a comparative study of the height catch-up rate in preterm small for gestational age (SGA) infants during early childhood by gestational age and identify the factors affecting short stature in comparison to full-term SGA infants.

METHODS

449 SGA infants (214 full-term infants, 73 infants with gestation of less than 32 weeks, and 162 infants with gestation of more than 32 weeks but less than 37 weeks) from 25 institutions in Japan were assessed for catch-up (> or = -2SD) rate in growth by measuring for length/height at 1 year, 3 years and 5 years of age and the risk factors for no catch-up (< -2SD) at 5 years.

RESULTS

The overall length/height catch-up rate was 68% at 1 year, 89% at 3 years and 88% at 5 years. The catch-up rate at 3 and 5 years of age in the group with gestation of less than 32 weeks had a rate of 74%, which was significantly less than the other two groups (approximately 90%). A significant factor associated with short stature at 5 years in the group with gestation of less than 32 weeks was the lower length SD score at time of birth, and for preterm infants born more than 32 weeks of gestation and full-term infants, significant factors were the lower maternal height and head circumference at birth.

CONCLUSION

SGA infants born less than 32 weeks of gestation had a higher risk of no catch-up and different factors affecting catch-up compared to preterm SGA infants of gestation more than 32 weeks and full-term SGA infants.

Identification of newborns with Fetal Growth Restriction (FGR) in weight and/or length based on constitutional growth potential

This study was carried out to build statistical models for defining FGR (Fetal Growth Restriction) in weight and/or length after taking growth potential of an infant into account. From a cohort of pregnant women having given birth to 47,733 infants in 141 French maternity units, two statistical models gave individualized limits of birth weight and birth length (based on the 5th centile) below which, after adjustment for its individual growth potential, a newborn must be considered as FGR in weight and/or in length. A sample of 906 infants had measures taken of cord blood growth factors (IGF1, IGFBP3). The FGR(W) definition (weight<5th centile for growth potential) permitted the identification of infants who presented rates of maternal hypertension (13.6%) and of Apgar score at 5 min<6 (2.9%) higher than in the classical group SGA(W) (weight<5th centile for sex and gestational age) (9.6% and 2.2% respectively). By combining FGR(W) and SGA(W), a subgroup of infants, not currently recognized as SGA, presented very high rates of maternal hypertension (19.9%) and of low Apgar score (3.9%). Conversely a subgroup of infants, currently recognized as SGA(W), had rates as low as in the normal infants group, and had to be considered as "constitutionally small" (that is to say 24% of the SGA(W)). Combining FGR(W) and FGR(L) (length<5th centile of growth potential), 7.6% of infants appeared growth-restricted, and 1.8% appeared constitutionally small in weight and/or in length. The FGR(W)-FGR(L) infants showed the lowest mean values of IGF1 (126.2+/-3.2) and IGFBP3 (0.86+/-0.03). These new definitions of FGR(W) and FGR(L) could help to better identify infants at birth requiring neonatal care, and monitoring of growth catch-up and neurodevelopmental outcome.