Chapter 13 Nutritional Aspects of Diabetes

postprandial hyperglycemia increases with age and typically is more extreme in older individuals than in younger persons with comparable fasting glucose con- centrations (5). As a result of this postprandial hyper- glycemia, more than half of adults 70 years and older will have fasting glucose levels within the normal range, and the diagnosis of type 2 diabetes may be missed if fasting glucose values are used for diagnosis. Latent autoimmune diabetes in adults (LADA) represents a slow, progressive form of type 1 diabetes that is frequently confused with type 2 diabetes; however, the presence of autoantibodies suggests that it is, like type 1 diabetes, an autoimmune disease. It may account for as much as 10% of cases of insulin-requir- ing diabetes in older adults. Persons with LADA are typically older than 35 years and non-obese. Their dia- betes may be controlled initially with nutrition therapy, but within a relatively short period of time a need for glucose-lowering medications and progression to insulin treatment are required. When insulin therapy is required, they generally need to be treated aggressively with a basal-bolus insulin regimen (6).

The physiology of aging includes changes in the pharmacokinetics of both insulin and glucose-lowering medications. Treatment must take into consideration changes in drug absorption, distribution, metabolism, and clearance, and these alterations affect individual drug choices and dosing decisions. Hypoglycemia is often a risk of diabetes treatment in older adults. Glucose counter-regulation involving glucagon, epi- nephrine, and growth hormone responses diminish with age, which may contribute to the reduction in the usual warning symptoms for hypoglycemia.

DIAGNOSIS OF DIABETES Diagnosis can be made based on HbA1c, fasting plasma glucose (FPG), an oral glucose tolerance test (OGTT), or random plasma glucose levels. The HbA1c has several advantages to the FPG and OGTT, includ- ing greater convenience (as fasting is not required), greater preanalytical stability, and less day-to-day per- turbations during stress and illness. Normoglycemia is defined as a FPG level less than 100 mg/dL (5.5 mmol/L) and a 2-hour postglucose level less than 140 mg/dL (7.7 mmol/L). Prediabetes is defined as an FPG level greater than 100 mg/dL (5.5 mmol/L) and less than 126 mg/dL (7 mmol/L), a 2-hour postglucose level less than 199 mg/dL (11 mmol/L), or an HbA1c of 5.7% to 6.4%. The current criteria for diagnosis of diabetes in older adults are the same as those for younger adults. The American Diabetes Association has the following criteria for diagnosis of diabetes (7):

● HbA1c 6.5% or higher OR ●

Fasting plasma glucose (FPG) levels at or above 126 mg/dL (7 mmol/L)a

OR ●

Two-hour plasma glucose at or above 200 mg/dL (11.1 mmol/L) during an OGTTa

OR ●

In a patient with classic symptoms of hyperglyce- mia or hyperglycemic crisis, a random plasma glucose at or above 200 mg/dL (11.1 mmol/L)

aIn the absence of unequivocal hyperglycemia, the result should be confirmed by repeat testing.

TREATMENT GOALS

The management of diabetes in older adults can be complicated by their clinical and functional heteroge- neity. Some older individuals may have developed dia- betes years earlier and may have significant complications, or they may have been well controlled and are without significant complications; others may be newly diagnosed but may have had years of undiag- nosed diabetes with resultant complications; and others may have recent-onset diabetes with few or no compli- cations. Some older adults with diabetes are frail, with substantial diabetes-related comorbidities or limited physical or cognitive functioning. Other older individ- uals with diabetes have minimal comorbidities and are active. Therefore, providers caring for older adults with diabetes must take this heterogeneity into consideration when setting and prioritizing treatment goals. The American Diabetes Association framework for consid- ering treatment goals is listed in Table 13.1 (see page 178 [7]).

There are few long-term studies in older adults demonstrating the benefits of intensive glycemic, blood pressure, and lipid control. Persons with longer life expectancy should receive diabetes care with goals similar to those for younger adults. It is suggested that less intensive glycemic target goals be set for persons with intermediate remaining life expectancy, high treat- ment burden, hypoglycemia vulnerability, and fall risk. However, for individuals with limited remaining life expectancy, glycemic goals should be set to avoid acute complications of diabetes (7).

As for all patients, medical nutrition therapy, dia- betes self-management education, and ongoing diabe- tes self-management support (particularly regarding healthy food choices and physical activity) are essen- tial for older adults and their caregivers. To be relevant and effective, educational and support efforts must be individualized.

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