Insulin sensitivity in Turner's syndrome: Influence of GH treatment

Objective: Excessive GH secretion may lead to secondary diabetes mellitus, while prolonged GH treatment may accelerate the onset of type 2 diabetes mellitus in predisposed individuals. Turner's syndrome (TS) patients are a population at risk since they have reduced glucose tolerance (GT) spontaneously and because they are usually treated with high doses of GH. Design and methods: The aim of the study was to evaluate insulin sensitivity (IS) and glucose tolerance (GT) in a group of TS patients treated with GH for a period of 6 years. Forty-seven TS girls were included in the study. GH was administered at a mean weekly dosage of 0.35 mg/kg, injected subcutaneously over 6-7 days. GT was assessed according to the criteria of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. IS was evaluated with the quantitative insulin sensitivity check index (QUICK-I). Results: No significant increase of impaired GT was observed in the patients during the follow-up period, while a reduced IS was detected. IS in TS patients was already lower than in prepubertal controls (P < 0.001) before starting treatment and further decreased during the first year of therapy (P < 0.05), and then remained stable over the following years. No correlation was found between QUICK-I, body mass index, years of treatment, onset and duration of puberty. One patient became diabetic during the course of treatment. Conclusions: GH treatment in TS girls does not significantly increase the prevalence of impaired GT or type 2 diabetes mellitus, while it does, however, decrease IS.