Impact of Somatostatin Analogs vs. Surgery on glucose metabolism in acromegaly: Results of a 5 years observational, open, prospective study

Objective. To investigate the 5-yr impact of surgery and somatostatin analogues (SSA) on glucose metabolism in acromegaly. Design. Observational, prospective, comparative, non randomized. Patients. 100 patients (48 women, 52 men, median age 49 yrs). Treatment with SSA only (group A; n=34), SSA followed by surgery (group B; n=20), surgery only (group C; n=30), and surgery followed by SSA (group D; n=16). Results. At diagnosis, 28% had impaired glucose tolerance (IGT) and 22% had diabetes mellitus; fasting glucose levels (4.13-10.60 mmol/L) were best predicted by age (t=2.88, p=0.0049) and disease duration (t=1.99, p=0.049). After 60 months, fasting glucose levels reduced (-4.9+/-19.7%) in group A only while they did not change in the other groups. In the 68 non diabetic patients at baseline, fasting glucose levels increased by 0.7+/-11.2%, 7.5+/-10.3%, 4.3+/-10.4% and 4.3+/-14.8% (p=0.28), from group A to D, respectively. Percent change of fasting glucose in all patients receiving SSA was 1.9+/-12.3% and in those non receiving SSA was 6.4+/-10.8% (p=0.13). Overall, prevalence of new onset of diabetes during SSA treatment was 9 of 55 (16.4%) vs. 3 of 23 after surgery (13.0%, p=0.98). Deterioration of glucose tolerance was correlated with increased BMI (r=0.49, p<0.0001) and not with use of SSA or surgery (r=0.06, p=0.53), control or not of GH (r=-0.10, p=0.31) and IGF-I (r=-0.12, p=0.22). Conclusions. The results of this study demonstrate a similar deterioration of glucose tolerance after 60 months in patients receiving SSA or cured with surgery. Increase in BMI was the major predictor of deterioration of glucose tolerance.