Endocrine Abstracts

Background: In acromegaly, carbohydrate metabolism disorders (CMD) are frequently observed. The effect of therapy of acromegaly on pathogenesis of CMD is not clear.

Aim: To assess the effect of somatostatin analogues (SSA) on pathogenesis of carbohydrate metabolism disturbance in acromegaly.

Patients and methods: 103 acromegaly patients were examined (31 men, 72 women; age 54 (46–61) years; 60 had newly diagnosed acromegaly (NA), 23 receiving SSA, 20 after transsphenoidal surgery (TSS). We analyzed fasting plasma insulin and glucose levels (FPI and FPG), HbA1c, the Matsuda, and HOMA-IR indices, area under insulin curve in the first 30 min (AUCins.30) and from 30 to 120 min of oral glucose tolerance test (AUCins.30–120). In 23 NA patients we assessed these parameters after 3 and 6 months of SSA therapy (12 patients) and TSS (11 patients).

Results: The prevalence of CMD in NA, SSA, and TSS groups was 52, 87, and 35% respectively. Levels of HOMA-IR index and FPI did not differ between SSA and TSS groups, but were considerably lower compared to the NA group (HOMA-IR 1.7 (IQR 0.7–3.1) vs 3.3 (2.0–7.4), P=0.008; FPI 46.0 (IQR 17.1–88.00) vs 90.0 (55.3–179.5) mU/l, P=0.002). Early insulin secretion estimated by AUCins.30 was severely reduced in the SSA group compared to the NA and TSS groups (P<0.01). Among 12 prospective SSA-treated patients, the reduction of IGF1 after 6 months coincided with a decrease of FPI and HOMA-IR (both P<0.05), and an increase of the Matsuda index (P=0.068). SSA-treatment resulted in a considerable reduction of early insulin secretion (AUCins.30) during an OGTT compared to the TSS group, while the reduction of AUCins.30–120 was similar between these groups.

Conclusions: Despite reduction of IGF1 levels and insulin resistance during SSA therapy and after TSS, the decrease of early insulin secretion on SSA therapy leads to the development of CMD.