Prevalence of Abnormal Glucose Metabolism in Acromegaly & Impact of Treatment Modalities on Glucose Metabolism

Objective: To determine the frequency of diabetes mellitus impaired glucose tolerance and impaired fasting glucose in Pakistani patients with acromegaly and to establish the impact of the intervention (surgery/ medical) on glucose metabolism. Methods: Eighty-nine patients fulfilling the endocrine society criteria for acromegaly diagnosis were included. A data of baseline, growth hormone (GH), Insulin-like growth factor-1 (IGF-1) level, Hemoglobin A1C (HbA1C), fasting blood glucose (FBG), and random blood glucose (RBS) levels were reviewed before and after the intervention (surgery/medical therapy). Normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and diabetes mellitus (DM) were defined based on the 2003 ADA criteria. Patients were grouped into normoglycemic (NGT) and dysglycemic (IFG, IGT, and DM) based on FBS, RBS, and HbA1C. Results: Major risk factors for dysglycemia included age (15-45 years), male sex (33.70%), obesity (45.7%), and macroadenoma (76%). Both mean GH levels (58.29 vs. 54.36 ng/dl) and IGF-1 levels (862.98 vs. 824.32 ng/dl) were higher among the normoglycemic than dysglycemia. Pre-surgery, NGT, IFG, IGT, IFG, and IGT combined and DM were found in 48.31, 5.61, 1.1, 5.61, and 39.32 % of the subjects, respectively. Post-surgery, HbA1C improved in 79.5%, deteriorated in 6.8%, and remained the same in 13.6%. Similarly, it improved in 67.4.7% post-medical therapy. Both FBS and RBS improved post-surgery and medical therapy. Further, the number of anti-diabetic drugs used also decreased post-surgery. Conclusion: Dysglycemia is more common among patients with acromegaly as compared to the general population and tends to be poorly controlled in untreated acromegaly. Glycemic control improves significantly after the surgery and medical therapy. Keywords: Acromegaly, Diabetes Mellitus, Transsphenoidal surgery