Diabetes mellitus is a common metabolic disorder affecting elderly people. Although it is recognized by its effects on carbohydrate metabolism to cause hyperglycemia, diabetes mellitus usually also affects lipid and protein metabolism. With time, effects of diabetes on the cardiovascular system, the kidneys, the retina, and the peripheral nervous system, often referred to as long-term complications of diabetes, substantially increase mortality and morbidity in older adults. Furthermore, diabetes may accelerate the risk and contribute to worse outcomes for other common age-related disorders. In general, diabetes mellitus in older adults is underdiagnosed and undertreated. A growing body of evidence assessing outcomes of interventions and an increasing number of therapeutic options for diabetes management has increased the importance of making a diagnosis and offering appropriate intervention strategies to elderly patients who have this potentially devastating disorder. There is also growing evidence of the ability to prevent the development of diabetes, including in older people. Management of diabetes is often considered to be synonymous with treatment of hyperglycemia. However, it is now recognized that appropriate diabetes management of an older patient must be much broader, addressing many factors that contribute to long-term complications.
Diabetes mellitus is a heterogeneous set of disorders affecting multiple body systems; however, diagnostic criteria are based on documentation of elevated circulating blood glucose levels. Because glucose levels vary during the course of the day, and even in the fasting state form a continuous variable in populations, the definition of a single cut point that separates normal from abnormal is somewhat arbitrary. The challenge of establishing appropriate diagnostic criteria for elderly subjects is made more difficult by well-described effects of aging on glucose metabolism (summarized later in this chapter in the section on “Effects of Aging”). Similar to criteria for hypercholesterolemia and hypertension, the diagnostic criteria for diabetes mellitus are based on values that predict poor outcomes in population studies.
Table 109-1 summarizes the currently accepted diagnostic criteria, which were established by an expert panel convened by the American Diabetes Association (ADA) and published in 1997 with a follow-up report in 2003.
Table 109-1 1997 and 2003 American Diabetes Association Diagnostic Criteria for Diabetes Mellitus, Impaired Glucose Tolerance, and Impaired Fasting Glucose |Favorite Table|Download (.pdf)
Table 109-1 1997 and 2003 American Diabetes Association Diagnostic Criteria for Diabetes Mellitus, Impaired Glucose Tolerance, and Impaired Fasting Glucose
Classic diabetes symptoms plus a random glucose level ≥200 mg/dL (11.1 mmol/L)
Fasting* glucose level ≥126 mg/dL (7.0 mmol/L)†
Glucose level ≥200 mg/dL (11.1 mmol/L) at 2 hours during a standard OGTT†
Impaired glucose tolerance (IGT)
Glucose level ≥140 mg/dL (7.8 mmol/L) and <200 mg/dL (11.1 mmol/L) at 2 hours during a standard OGTT
Impaired fasting glucose (IFG)
Fasting glucose level ≥100 mg/dL (5.6 mmol/L) and <126 mg/dL (7.0 mmol/L)