Endocrine Abstracts

Introduction: Acromegaly is associated with increased cardiovascular morbidity and mortality, in part, as a consequence of the increased insulin resistance that frequently accompanies GH hypersecretion. Glucose tolerance may worsen in patients treated with somatostatin analogs (SSA).

Objective: To compare the long term effects of SSA treatment to successful surgery on glucose metabolism in Cretan acromegalic patients.

Design and methods: This is a cross-sectional study. We studied 22 normoglycemic acromegalics (12 female/10 male, age 53±14). Fifteen patients were on SSA treatment (seven were controlled) and seven patients were surgically cured. The median period of SSA treatment was 10 years. Twenty seven age-and sex-matched healthy subjects were studied as controls. Glucose homeostasis was studied using the indexes stated below, at baseline and following an oral glucose challenge (OGTT 75 g). The areas under the response curves of glucose (AUC_GLUC) and insulin (AUC_INS) during OGTT were estimated.

Results: On average, both groups of acromegalic patients had significantly elevated fasting glucose, compared to controls (P_surg=0.01, P_ssa<0.001). AUC_GLUC after OGTT was significantly elevated in all SSA-treated patients (P_{ssa controlled}=0.04, P_{ssa not controlled}=0.003). AUC_INS was significantly decreased only in controlled SSA-treated acromegalics (P=0.035). No significant differences in AUC_GLUC or AUC_INS were observed between surgically cured acromegalics and the control group. Basal insulin secretion evaluated by HOMA-B%, was significantly decreased in all SSA-treated patients compared to controls (P=0.001) but no difference was observed in basal and OGTT-derived insulin resistance evaluated by HOMA-IR, QUICKI and ISIComposite between acromegalics and controls.

Conclusion: Cretan acromegalics, even if cured had elevated fasting plasma glucose. SSA treatment resulted in higher glucose values in the fasting state and after OGTT, because of impaired insulin secretion, but had no impact on insulin resistance.