Glucose metabolism in elderly patients with type 2 diabetes mellitus

Type 2 diabetes mellirus contributes to excess morbidity and mortality among the elderly. Few studies have compared parameters of glucose metabolism in elderly subjects with and without type 2 diabetes. In order to characterize glucose metabolism in the elderly, we performed frequently sampled intravenous glucose tolerance tests modified to include an insulin infusion on 23 subjects (11 diabetics and 12 controls) all of whom were over the age of 65 The acute insulin response to glucose (AIRglu), the glucose disappearance constant (Kg), and indices of insulin sensitivity (Si) and glucose effectiveness (Sg) were determined using the minimal model of glucose kinetics. Compared with controls, elderly diabetics had significantly lower values for Si (mean values: 1.285 min^-1/μU/ml in diabetics vs. 2.390 min^-1/μU/ml in controls, p = 0.009), Sg (mean values: 1.332 min^-1 in diabetics vs. 1.677 min^-1 in controls, p = 0.029) and Kg (mean values: 1.255 %min^-1 in diabetics vs. 1.703 %min^-1 in controls, p = 0.009). AIRglu was also lower in diabetics (mean values: 4 min*μU/ml in diabetics vs. 69 min*μU/ml in controls, p < 0.001). Similar to younger subjects with type 2 diabetes, these results suggest that type 2 diabetes in the elderly is characterized by alterations in insulin release and insulin sensitivity as well as changes in non-insulin mediated glucose disposal. Further study will be required to determine the relative importance of each of these mechanisms in the pathogenesis of type 2 diabetes in the elderly.

Duke Scholars

Author David A D'Alessio Medicine, Endocrinology, Metabolism, and Nutrition