MON-LB50 Poor Response to Pre-Surgical Treatment With Somatostatin Receptor Ligands Is Associated With Diabetes Mellitus in Patients With Acromegaly

Abstract

Introduction: somatostatin receptor ligands (SRL) represent the first-line medical therapy in acromegaly patients who were not cured by surgery and in those where surgical remission is unlikely. It is well known that SRL may negatively act on insulin secretion, with consequent hyperglycemia and diabetes mellitus (DM). Purpose: To evaluate whether the degree of response to surgical pre-treatment with SRL predicts alterations in blood glucose levels.Patients and Methods: We retrospectively studied 181 patients attending the Unit of Neurosurgery of our Hospital prior to transsphenoidal surgery. All patients had a biochemical and radiological diagnosis of acromegaly (nadir GH during OGTT >0.4 ng/mL; IGF-I above age-standardized UNL and pituitary adenoma at MRI scans); diagnosis of DM and impaired fasting glucose (IFG) was performed on fasting blood glucose (FBG) according to the American Diabetes Association guidelines; all parameters of the pituitary axes were determined. The response to SRL treatment was determined as percent change of GH levels. Data are presented as mean±SD; Continuous data normally distributed were analyzed using a two-tailed Student’s t-test to compare two groups, and one-way ANOVA to compare several groups, followed by the Bonferroni post-hoc procedure for pairwise comparison of groups after the null hypothesis was rejected (p<0.05); categorical data were analyzed by chi-squared test.Results: 97 (54%) patients with acromegaly underwent pre-surgical treatment with SRL; we found no difference in age (53±11 vs. 51±12 years; p=NS) and sex (M/F: 51/46 vs. 43/41; p=NS) between SRL treated and non-treated patients. We found no difference in FBG between SRL treated vs. non-treated patients. In contrast, we found increased proportions of IFG and DM patients in SRL treated when compared to non-treated patients (euglycemic: 45%, IFG: 42%, DM: 13% vs. euglycemic: 70%, IFG: 22%, DM: 8%, respectively; p=0.006). In addition, SRL treatment increased the odds ratio of IFG and DM (OR 4.7; 95%CI 2.1-10.3). When considering the degree of response to SRL pre-surgical treatment, we found that poor responders displayed at the time of surgery glycemias diagnostic of DM; whereas, good responders displayed glycemias in the range of IFG (percent change in GH levels 50±35% vs 79±22%, respectively; p<0.05).Conclusions: Our findings show that the proportion of patients with acromegaly undergoing surgery with glycemic levels diagnostic of DM, is modest. Interestingly, pre-treatment with SRL represents an independent risk factor for high glucose levels. Moreover, among patients on SRL pre-treatment, the ones that respond poorly are the ones that at the time of surgery display glycemias diagnostic of DM. Our findings suggest that SRL pre-treatment may predispose to worsened glucose metabolism but selectively affecting those patients in whom biochemical control is not reached.