Comparison between the growth response to growth hormone (GH) therapy in children with partial GH insensitivity or mild GH deficiency

Response to growth hormone according to provocation test results in idiopathic short stature and idiopathic growth hormone deficiency

PURPOSE

To investigate growth response in children with either idiopathic short stature (ISS) or growth hormone (GH) deficiency (GHD).

METHODS

The data of prepubertal GHD or ISS children treated using recombinant human GH were obtained from the LG Growth Study database. GHD children were further divided into partial and complete GHD groups. Growth response and factors predicting growth response after 1 and 2 years of GH treatment were investigated.

RESULTS

This study included 692 children (98 with ISS, 443 partial GHD, and 151 complete GHD). After 1 year, changes in height standard deviation score (ΔHt-SDS) were 0.78, 0.83, and 0.96 in ISS, partial GHD, and complete GHD, respectively. Height velocity (HV) was 8.72, 9.04, and 9.52 cm/yr in ISS, partial GHD, and complete GHD, respectively. ΔHt-SDS and HV did not differ among the 3 groups. Higher initial body mass index standard deviation score (BMI-SDS) and midparental height standard deviation score (MPH-SDS) were predictors for better growth response after 1 year in ISS and the partial GHD group, respectively. In the complete GHD group, higher Ht-SDS and BMI-SDS predicted better growth response after 1 year. After 2 years of GH treatment, higher BMI-SDS and MPH-SDS predicted a better growth outcome in the partial GHD group, and higher MPH-SDS was a predictor of good growth response in complete GHD.

CONCLUSION

Clinical characteristics and growth response did not differ among groups. Predictors of growth response differed among the 3 groups, and even in the same group, a higher GH dose would be required when poor response is predicted.

Significance of Direct Confirmation of Growth Hormone Insensitivity for the Diagnosis of Primary IGF-I Deficiency

Primary insulin-like growth factor-I (IGF-I) deficiency is a synonym of growth hormone (GH) insensitivity (GHI), however the necessity of direct confirmation of GH resistance by IGF-I generation test (IGF-GT) is discussed. GHI may disturb intrauterine growth, nevertheless short children born small for gestational age (SGA) are treated with GH. We tested the hypothesis that children with appropriate birth size (AGA), height standard deviation score (SDS) <−3.0, GH peak in stimulation tests (stimGH) ≥10.0 µg/L, IGF-I <2.5 centile, and excluded GHI may benefit during GH therapy. The analysis comprised 21 AGA children compared with 6 SGA and 20 GH-deficient ones, with height SDS and IGF-I as in the studied group. All patients were treated with GH up to final height (FH). Height velocity, IGF-I, and IGF binding protein-3 (IGFBP-3) concentrations before and during first year of treatment were assessed. Effectiveness of therapy was better in GHD than in IGF-I deficiency (IGFD), with no significant difference between SGA and AGA groups. All but two AGA children responded well to GH. Pretreatment IGF-I and increase of height velocity (HV) during therapy but not the result of IGF-GT correlated with FH. As most AGA children with apparent severe IGFD benefit during GH therapy, direct confirmation of GHI seems necessary to diagnose true primary IGFD in them.

Auxological characteristics of pediatric patients with permanent or transient isolated growth hormone deficiency. Response to treatment and final height

INTRODUCTION

Treatment with recombinant human growth hormone (rhGH) has been shown to improve adult height in pediatric patients with GH deficiency (GHD). However, reassessment of patients after they reach their final height shows some of them have permanent GH deficiency (PGHD), while others had a transient deficiency (TGHD). The study objective was to assess, in a cohort of pediatric patients with GHD, potential differences in response to treatment with rhGH depending on whether deficiency is permanent or transient.

MATERIALS AND METHODS

A retrospective study of 89 patients with GHD, who were monitored from diagnosis to adult height. Clinical, auxological, radiographic and laboratory variables were collected at diagnosis, after the first year of treatment, and when they had reached their adult height.

RESULTS

PGHD was found in 28% of patients. Initial height was -2.46 ± 0.86 SD and -2.24 ± 0.68 SD in subjects with PGHD and TGHD respectively. Peak GH level at diagnosis was 4.26 ± 2.78 and 6.20 ± 2.01 ng/mL (p < 0.01) in the PGHD and TGHD groups respectively. After the first year of treatment, increase in growth velocity was greater in the PGHD group: 4.33 ± 3.53 SD vs. 2.95 ± 2.54 SD in the PGHD group (p = 0.043). Final height was -0.81 ± 0.87 SD in the PGHD and -0.95 ± 0.83 SD in the TGHD group (p = 0.47).

CONCLUSIONS

Patients with PGHD had a better short- and long-term response to rhGH. They also showed lower GH levels in stimulation tests at diagnosis, as previously reported.