ABSTRACT
OBJECTIVE: To evaluate whether two different regimens of weekly injections could lead to similar auxological and metabolic effects in children with growth hormone deficiency (GHD). DESIGN: 32 GHD children (25 males, mean age 10.5 ± 2.2 yr) were randomly assigned to receive daily (group A, 16 patients) or TIW (group B, 16 patients) GHT for 12 months. METHODS: Auxological parameters, insulin-like growth factor-I (IGF-I), glucose and insulin during OGTT, glycosylated hemoglobin (HbA1c), lipid profile, the oral disposition index (DIo), the homeostasis model assessment estimate of insulin resistance (Homa-IR), and the insulin sensitivity index (ISI). RESULTS: After 12 months, both groups showed a significant and comparable improvement in height (p < 0.001) and IGF-I (p < 0.001). As regards the metabolic parameters, in both groups, we found a significant increase in fasting insulin (p < 0.001 and p = 0.026) and Homa-IR (p < 0.001 and p = 0.019). A significant increase in fasting glucose (p = 0.001) and a decrease in ISI (p < 0.001) and DIo (p = 0.002) were only found in group A. CONCLUSIONS: The TIW regimen is effective and comparable with the daily regimen in improving auxological parameters and has a more favorable metabolic impact in GHD children. This trial is registered with ClinicalTrials.gov NCT03033121.
ABSTRACT
OBJECTIVE: GH treatment (GHT) can lead to glucose metabolism impairment through decreased insulin sensitivity and impaired pancreatic ß-cell function, which are the two key components of the pathogenesis of diabetes. Therefore, in addition to insulin sensitivity, during GHT it is very important to perform a reliable evaluation of insulin secretion. However, conflicting data exist regarding the insulin secretion in children during GHT. C-peptide provides a more reliable estimate of ß-cell function than insulin, but few studies evaluated it during GHT. Our aim was to assess the usefulness of C-peptide in the evaluation of insulin secretion in GH deficiency (GHD) children. DESIGN: In 48 GHD children, at baseline and after 12 and 24months of GHT, and in 56 healthy subjects we evaluated fasting and glucagon-stimulated (AUCCpep) C-peptide levels in addition to other commonly used secretion indexes, such as fasting and oral glucose tolerance test-stimulated insulin levels (AUCINS), Homa-ß, and insulinogenic index. The main outcomes were the change in C-peptide during GHT and its correlation with the auxological and hormonal parameters. RESULTS: At baseline GHD children showed a significant lower AUCCpep (p=0.006), while no difference was found for the other indexes. Both fasting C-peptide (beta 0.307, p=0.016) and AUCCpep (beta 0.379, p=0.002) were independently correlated with IGF-I SDS, while no correlation was found for all other indexes. After 12months an increase in Homa-ß (p<0.001), fasting C-peptide (p=0.002) and AUCCpep (p<0.001) was found. At multivariate analysis, only fasting C-peptide (beta 0.783, p=0.001) and AUCCpep (beta 0.880, p<0.001) were independently correlated with IGF-I SDS. CONCLUSIONS: C-peptide, rather than the insulin-derived indexes, has proved to be the most useful marker of insulin secretion correlated to IGF-I levels in GHD children. Therefore, we suggest the use of glucagon test both as diagnostic test for the GH assessment and as a useful tool for the evaluation of insulin secretion during GHT in children.
