What Geriatricians Should Know About Diabetes Mellitus

Aging is associated with a progressive decline in glucose tolerance to the extent that most elderly people have abnormal carbohydrate metabolism and an increasing proportion have type II (non-insulin-dependent) diabetes mellitus. This review focuses on the pathophysiology, evaluation, and treatment of this process and emphasizes that although normal glucose tolerance and diabetes mellitus are strictly defined, there is a large subset of elderly individuals who, although nondiabetic, fall into the carbohydrateintolerant zone. This diminished carbohydrate tolerance is the result of a decrease in insulin sensitivity and an impairment of pancreatic β-cell function, which both may result, in part, from changes in sensitivity to dietary carbohydrate associated with aging. Similar defects in insulin action and insulin secretion are also present in type II diabetes. Although the macro- and microvascular complications of diabetes mellitus occur in older individuals with hyperglycemia, carbohydrate intolerance does not appear to be associated with microvascular events. Thus, therapeutic decisions must be based on an understanding of the degree of impairment in carbohydrate tolerance and the risk of acute and chronic complications associated with this abnormality. This is of even more importance when managing a group of subjects whose life expectancy is reduced and who may be less amenable to interventions that could include diet, oral sulfonylureas, or insulin. Furthermore, although all these interventions may result in a decline in glucose level and improved health, they are also associated with risks, some of which may be life threatening in this population.