Endocrine Abstracts

Purpose: To evaluate whether the degree of response to surgical pre-treatment with somatostatin receptor ligands (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 diagnosis of acromegaly (nadir GH during OGTT >0.4 ng/ml; and IGF-I above age-standardized UNL); diagnosis of diabetes (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±s.d.; 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.