Can glucose intolerance and/or diabetes be predicted in patients treated with rhGH?

Various studies have convincingly shown that recombinant human growth hormone (rhGH) therapy accelerates growth significantly in children with growth retardation secondary to chronic renal insufficiency (CRI) and after renal transplantation (RTx). rhGH therapy appeared remarkably safe intermediate-term, but paediatricians are concerned about the potential adverse effects on glucose homeostasis and insulin action. Particularly in children with CRI and after RTx, pre-existing insulin resistance may be aggravated by exogenous rhGH therapy. Patients after RTx had significantly higher pretreatment insulin levels than controls (p < 0.001). Various studies in both patient groups showed that one year of rhGH therapy at 4 i.u./m2/day did not impair glucose tolerance but significantly increased plasma insulin levels (p < 0.001). No patients developed impaired glucose tolerance or permanent diabetes mellitus (DM), but from these studies, it was concluded that euglycemia was maintained at the expense of increased insulin levels. The long-term consequences of the compensatory hyperinsulinaemia are not yet known. Although permanent DM has not been reported in any of the rhGH trials in renal patients, it cannot be excluded that some patients with CRI or after RTx may develop impaired glucose tolerance and/or permanent DM during long-term rhGH therapy, particularly those with risk factors such as familial type II DM and obesity. Long-term studies, including careful monitoring of carbohydrate metabolism, are required.