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

To evaluate glucose homeostasis in children with growth hormone (GH) deficiency (GHD) receiving long-term replacement therapy. 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. 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 A mu U/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. 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.