Diabetes mellitus – especially type 2 diabetes (T2DM) – is becoming increasingly common among US residents aged 65 and older. In 2010, 10.9 million (26.9%) of this population had diabetes, and the number is expected to continue rising to 26.7 million by 2050.1,2 There are several reasons for this phenomenon, including the aging of the population, decreased mortality rates among individuals with diabetes, and the obesity epidemic.3 The aging process also plays a role by contributing to insulin resistance and impaired beta-cell function, which in turn contribute to the pathogenesis of T2DM in older adults.3 Aging is associated with a variety of pathogenic processes, including accumulation of fat in muscle and liver tissues, as well as reduced rates of mitochondrial activity in the brain, and defects in insulin secretion.3
A recent review of four randomized clinical trials, ranging in size from 1791 to 11440 patients, examined glycemic control in aging patients with T2DM.3 The authors set out “to synthesize the available evidence and provide clinicians with practical information to guide discussions about glycemic treatment with these vulnerable patients.” They note that the evidence regarding benefits and harms of standard vs intensive glycemic control are derived from trials that focused on younger patients and used surrogate end points, rather than clinical outcomes. Their review extrapolates from these limited data to offer “evidence-informed” suggestions about glycemic control in older adults.
What Makes Older Adults Different?
In older adults, the classic symptoms of diabetes (eg, polyuria and polydipsia) may be absent and the patient may be asymptomatic. Diabetes may be discovered only on routine laboratory studies. On the other hand, diabetes may be symptomatic and present with dehydration, confusion, incontinence, and diabetes-related complications (eg, neuropathy or nephropathy)3 Older adults are more likely to have abnormal 2-hour plasma glucose during an oral glucose tolerance test (OGTT). The authors caution that the hemoglobin A1c (HbA1C) level may not accurately reflect hyperglycemic in the setting of conditions common in this age group (eg, anemia, recent blood transfusions, treatment with erythropoietin, or chronic kidney disease).
Glycemic control is the cornerstone of all diabetes treatment; but setting the glycemic target is more complicated in the elderly because, while intensive glycemic control may lower the risk of some long-term complications (eg, microvascular disease), it may also increase the risk of harm (ie, hypoglycemia). So decisions about glycemic treatment “involve trade-offs between these possible benefits versus the potential harms and burdens of treatment.”3 Recent guidelines encourage individualizing glycemic targets in older adults.4,5,6