Endocrine Abstracts

Introduction: Impaired glucose tolerance and insulin resistance are frequently associated with acromegaly. The aim of this study was to assess the impact of long-acting somatostatin analog treatment on glucose homeostasis in acromegalic patients.

Patients and methods: In this prospective study 16 naïve acromegalic patients (eight females, eight males; aged 51.5±10.9 years) were studied before and after 3-month therapy with long-acting somatostatin analog (i.e. octreotide LAR 20 mg i.m. every 28 days). Diagnosis of active acromegaly was established on the basis of widely recognized criteria. In each patient glucose and insulin concentrations were assessed during the 75 g oral glucose tolerance test (OGTT) before and after 3 months of treatment. HbA1c levels were evaluated baseline and after 3 months of therapy. To estimate insulin sensitivity we performed hyperinsulinemic euglycemic clamp and calculated homeostasis model assessment (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI).

Results: We did not found any statistically significant change in plasma glucose concentrations either fasting or during OGTT (P>0.05). A significant reduction in HbA1c levels was observed (6.54±1.72% vs. 6.02±0.78%) after 3 months of treatment. A prominent decrease in insulin secretion during OGTT was found after octreotide LAR treatment compared to the baseline (4.4±2.0 vs 12.1±9.6 mIU/ml, P<0.001). After 3 months of therapy there was an improvement in insulin resistance: a significant reduction in HOMA-IR (0.92 vs 2.27, P<0.05) and a significant increase in QUICKI (0.39 vs 0.34, P<0.05) values. In euglycemic clamp method we found a statistically significant increase in glucose disposal rate, i.e. M value (4.52±2.34 vs. 2.37±1.24 mg/kg per min).

Conclusions: We concluded that the treatment of acromegaly with octreotide LAR improve insulin sensitivity and HbA1c levels, even if it does not show any effect on glucose concentrations during OGTT.

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 work was supported, however funding details unavailable.