Glucose homeostasis in GHD children during long-term replacement therapy: a case - control study

PURPOSE: To evaluate glucose homeostasis in children with growth hormone (GH) deficiency (GHD) receiving long-term replacement therapy. METHODS: We evaluated glucose, insulin, HOmeostasis Model Assessment (HOMA-IR), and HbA1c in 100 GHD children at diagnosis and during 5 years of therapy. One hundred healthy children comparable to patients were evaluated at baseline and after 1 and 5 years. RESULTS: No difference was detected at baseline between GHD patients and controls in glucose (79.58 ± 9.96 vs. 77.18 ± 8.20 mg/dl), insulin (4.50 ± 3.24 vs. 4.30 ± 2.60 µU/ml), HbA1c (5.20 ± 0.31 vs. 5.25 ± 0.33%) levels, and HOMA-IR (0.93 ± 0.72 vs. 0.86 ± 0.61). One year of GH was associated with a significant increase in insulin (7.21 ± 4.84, p < 0.001) and HOMA-IR (1.32 ± 0.98, p < 0.001) in GHD children, which became different from controls (p < 0.001 and p = 0.004). These parameters did not change further during the following years of treatment in GHD subjects. In contrast, controls did not show significant changes in insulin (4.40 ± 2.60) and HOMA-IR (0.82 ± 0.60) during the first year; however, at the fifth year of the study a significant increase in insulin (6.50 ± 3.50, p = 0.004) and HOMA-IR (1.29 ± 0.54, p < 0.001) was documented, making these parameters comparable between patients and controls. CONCLUSIONS: Our results suggest that growth hormone (GH) treatment is not associated with significant impairment of insulin sensitivity in GHD children. The slight impairment observed in GHD adolescents after long-term GH is comparable to that physiologically occurring in healthy pubertal subjects.