Endocrine Abstracts

Growth hormon (GH) counteracts the effects of insulin on glucose metabolism and GH excess may lead to insulin resistance (IR). Impaired glucose tolerance (IGT) and diabetes mellitus (DM) are frequently associated with acromegaly. Microalbuminuria (MAU) is a well established cardiovascular (CV) risk factor and a predictor of CV mortality in both diabetic and nondiabetic subjects.

The aim of this preliminary study was to investigate the MAU levels as a marker of CV disease in patients with acromegaly but without DM.

Forty-one acromegalics without DM with a mean age of 43.86±11.7 years, mean BMI 29.74±4.7 kg/m² and median disease duration 48 (IQR 21–108) months and age, sex and BMI matched 18 healthy controls were included. Patients and controls underwent OGTT and hormonal/biochemical evaluation and 24-hour urinary microalbumin excretion was measured. IR was evaluated with the homeostasis model insulin resistance index (HOMA-R). HOMA-R was not different between patients and controls (P>0.05). Mean nadir GH level was 4.36±14.71 ng/ml. In nondiabetic patients with normal IGF-1 levels for age, HOMA R was found to be lower than nondiabetic patients with elevated IGF-1 levels for age (1.06±0.99 and 1.82±1.27, P<0.05). However, in nondiabetic patients HOMA-R values were not statistically different between patients who achieved the nadir GH level of less than 1 ng/ml after OGTT and who did not achieve the nadir GH level (P=0.063). We demonstrated a positive but weak correlation between HOMA-R values and MAU in nondiabetic acromegalic patients (R=0.105, P<0.05), but not in the control group. In conclusion, daily urinary albumin excretion in acromegalic patients seems to be correlated with IR (HOMA-R) even before devoloping overt DM. Since, both IR and presence of MAU are CV risk factors, MAU may be important in the assessment of nondiabetic acromegalic patients.