Endocrine Abstracts

Introduction: There is a well-established association between acromegaly and insulin resistance (IR). The abnormalities in glucose metabolism may be an important risk factor of cardiovascular morbid-mortality in these patients.

Objective: Evaluation of glucose metabolism abnormalities in a population of naïve acromegalic patients and its relationship with delay in diagnosis, gender, levels of insulin like growth factor 1 (IGF1) and GH.

Methods: Retrospective study of 98 acromegalic patients diagnosed between 1982 and 2011. Levels of glucose and insulin were evaluated during fasting and after 75 g oral glucose tolerance test. Homeostasis model assessment for insulin resistance (HOMA-IR) and for insulin secretion (HOMA-beta) was calculated using the following formulas: HOMA−IR index=(fasting insulin×fasting glucose)/22.5. HOMA-beta index=(20×fasting insulin (mU/ml))/(fasting glucose (mMol/l)−3.5).

Results: Seventeen patients had previous diagnosis of type 2 diabetes mellitus (T2DM), 42 had normoglycemia, five impaired fasting glucose (IFG), 12 impaired glucose tolerance (IGT), 10 IFG and IGT, four diagnosis of T2DM according to glucose fasting levels, four T2DM according to glucose levels at 120′ PTGO and four patients diagnosis of T2DM on both methods. Patients with previous T2DM were older (50.7±13.2 vs 40.8±14.0, P=0.03) and had higher levels of HOMA-IR index (11.3±11.3 vs 4.0±3.5, P=0.005) than normoglycemic patients. Although normoglycemic patients had higher levels of HOMA-beta index than patients on the other groups of glycemia, these differences were not statiscally significant (P=0.846). There were no statistically significant differences between groups in what concerns diagnosis delay, body mass index, levels of GH and IGF1. There was a positive correlation between IGF1 levels and HOMA-IR (r=0.306, P=0.013).

Discussion: The prevalence of T2DM in this population is higher than in portuguese population. A considerable proportion of patients presented intermediate hyperglycemia. In this analysis, age was the only factor predisposing to glucose metabolism alterations and T2DM. There is a correlation between insulin resistance and disease activity.