DIABETES MELLITUS AND IMPAIRED GLUCOSE TOLERANCE IN ACROMEGALIC PATIENTS

Abstract

Acromegaly is a disease caused by growth hormone (GH) overproduction. In this state, carbohydrate metabolism disturbance often occurs. Diabetes mellitus prevalence has been demonstrated between 19 and 56%, and impaired glucose tolerance prevalence between 5 and 46% in many groups of patients with acromegaly. The present study was designed to estimate diabetes mellitus and impaired glucose tolerance prevalence in a group of acromegalic patients assisted in the Endocrinology/Metabology Division of University Hospital of School of Medicine of Ribeirão Preto, São Paulo University (HCFMRP), attempting to also analyze their endocrine and metabolic characteristics. The patients were studied before any therapeutic intervention and were divided in three groups: diabetics, with impaired glucose tolerance and nondiabetics/non impaired glucose tolerance patients. We studied 55 acromegalic patients assisted in HCFMRP. We determined age, sex, weight, height, time of typical acromegalic symptoms upset, and blood GH and glucose during oral glucose tolerance test (oGTT): 0, 30, 60, 90 and 120 minutes. In 19 patients (39,5%) the basal insulin levels were determined in the first sample of the oGTT. Using this data, we calculated body mass index (BMI = weight (kg), divided by square height (meters)), and areas under curves of mean values of GH and glucose in blood during oGTT. Statistical analyzes were processed by Kruskal-Wallis, Mann Whitney and Spearman correlation tests.Among the 55 acromegalic patients studied, 15 (27,3%) were diabetics (DM), 9(16,4%) had impaired glucose tolerance (IG), and 31 (56,4%) did not have blood glucose disturbances (NL). Females were more frequent in DM and IG groups (66,7% in both groups), while women were minority in NL group (29%). DM and IG groups show similar age distribution (45,8+13,1 and 46,3+10,6 years, respectively), and significantly higher age than NL group (36,4+11,1 years; p<0,05). Between the 19 patients whose basal insulin level were obtained, 4 were of the DM group, 6 of the IG group and 9 of the NL group. Mean basal serum insulin level in acromegalic patients, even from the DM, IG or the NL group, was higher than that seen in normal adult population. There was no correlation between areas under GH and glucose curves during oGTT. We did not see statistical differences among the three groups in BMI, activity acromegaly time and area under GH curves during oGTT. In conclusion, we verified increased prevalence of glucose metabolism alterations among our acromegalic patients, associated with female gender, older age, and higher levels of basal serum insulin.