Diabetes mellitus in acromegaly: prevalence, pathophysiological particulars and treatment strategies

Abstract

The prevalence of diabetes mellitus in acromegaly is significantly higher than that in the general population. Carbohydrate metabolism abnormalities often precede other phenotypic manifestations of acromegaly. The review presents data on the prevalence of carbohydrate metabolism disorders in acromegaly and describes their pathophysiological characteristics and approaches to treatment. Growth hormone (GH) excess is recognized as a key factor of glucose homeostasis abnormalities due to decreased insulin sensitivity (resulting from active lipolysis) and direct stimulation of insulin secretion. Insulin-like growth factor 1 (IGF1) improves insulin sensitivity; however, the GH diabetogenic effects prevail over the insulin-sensitizing impact of IGF1. Surgical and radiation treatment for somatotropinoma may indirectly improve carbohydrate metabolism, because they decrease the GH levels. Treatment with first generation somatostatin analogues can both improve glycemic control due to decreased GH levels and worsen it due to deterioration of postprandial insulin release, especially in patients with already manifest carbohydrate metabolism disorders. The GH receptor antagonist pegvisomant blocks the effects of excess GH on the target tissues without suppressing insulin secretion, which results in better glucose control; treatment with this agent can be preferred in patients with acromegaly and diabetes mellitus. Management of carbohydrate metabolism disorders in acromegaly is done in accordance with general treatment principles for type 2 diabetes mellitus.