Endocrine Abstracts

Introduction: Acromegaly is associated with alterations of glucose metabolism. The effect of somatostatin analogues (SMS) and pegvisomant (PEG) on glucose metabolism is still argument of debate.

Study design: The purpose of this historical-prospective study was to compare, in a cohort of 47 patients with active acromegaly, the effects of SMS and PEG alone or in combination on glucose metabolism. All subjects were evaluated at baseline and at least 6 months after therapy changes with fasting chemistry evaluation and OGTT. All patients were initially treated with SMS; 21 were controlled (SMS-contr); those uncontrolled received pegvisomant in combination with SMS (PEG-SMS), and, thereafter only PEG (PEG).

Results: Fasting blood glucose was higher in groups receiving SMS (SMS, SMS–PEG) than at baseline or PEG even after correction for biochemical control of disease (P<0.0001). Mean glucose concentrations at OGTT’s were higher in SMS groups (P=0.0004; associated with a higher prevalence of IGT and DM) than in the PEG group. The insulin was reduced in all groups compared to baseline (P<0.05) regardless of the type of treatment. The insulin sensitivity, reduced at baseline, improved after therapy (HOMA-IR, QUICK-I), especially in groups with biochemical disease control (SMS-cont, SMS-PEG and PEG, P<0.05). Moreover, in subjects receiving SMS was observed a reduction in HOMA-β values.

Conclusion: PEG, at variance with SMS, is not associated with changes in blood glucose levels. Either SMS or PEG therapy were associated with improvement in insulin sensitivity, probably due to the reduction in GH levels or to the reduction of its action. The deterioration in glycaemic control observed with SMS may be secondary to inhibition on direct insulin secretion as suggested by the reduction in the values of HOMA-β. In conclusion, the type of medication used in acromegaly may have a significant impact on glucose metabolism.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.