In contrast, those at greater risk from the hypoglycemia associated with intensive glycemic control are people who are older and frail, have longer duration of diabetes, have macro- and microvascular complications and comorbidities, are unable to safely follow complex regimens, and have shorter life expectancy.
She also pointed to a 2010 retrospective cohort study that identified a U-shaped curve relationship between hemoglobin A1c and all-cause mortality and cardiac events, suggesting that “there is a threshold beyond which, if the control is tighter, then the risk of mortality increases.”
Medications used by older adults with diabetes also pose risks, as shown in a study published in 2011 of 99,628 emergency hospitalizations for adverse drug events among U.S. adults aged 65 years and older conducted during 2007-2009.
In that study, warfarin topped the list, but insulin was the second most common, and oral hypoglycemic agents were also in the top 5.
And those episodes of emergency hospitalization, another study found, were associated with a 3.4-fold increased risk for 5-year mortality.
“ It increases the risk of cognitive decline, depression, frailty, falls and fractures, functional decline, anxiety, and fear of hypoglycemia; and it lowers quality of life,” Dr. Munshi explained.
Other unintended consequences of strict glycemic control in older adults include difficulty coping with complex regimens, increased caregiver burden, loss of independence, and increased financial burden, she added.
Control in healthy adults
A valid question, Dr. Munshi said, is whether strict glycemic control might be appropriate for older adults who are still healthy.
She responded to that by explaining that there is a phenomenon of aging called homeostenosis, a physical limit beyond which homeostasis cannot be restored in the presence of stressors, such as hypoglycemia leading to a fall, hospitalization, delirium, and poor outcome.
Another reasonable question, she added, was whether strict glycemic control in older adults could be achieved more safely and with greater benefit by using newer agents with lower risks for hypoglycemia that have been found to have cardiovascular and renal benefits.
To that, she noted that it’s not clear whether those benefits are a result of glycemic control, that the duration of the trials has been short (2-3 years), and drug interactions and side effects in populations with multiple morbidities have not been studied. Moreover, “cost and availability need consideration,” she said.
And so, she concluded, “Is strict glycemic control in the elderly really worth the risk? My answer would be no.”
The case for ...
Dr. Suzuki, a professor in the division of diabetes, metabolism, endocrinology, rheumatology, and collagen diseases at Tokyo Medical University, argued that strict glycemic control in the elderly is not “meaningless.”
He began by pointing out that his country, Japan, is “one of the most highly aging societies in the world.”
His arguments were based on three points: The elderly population is “full of diversity;” HbA1c is “not a perfect marker of glycemic control;” and new glucose-lowering drug classes may have benefits beyond reduction of blood glucose levels.
He also noted that there is no consensus on the definition of “elderly.”
Most developed countries use age 65 years and older as the cut-off, but the United Nations defines being elderly as 60 years and older, whereas the International Diabetes Federation’s guideline for managing older people with type 2 diabetes, uses 70 and older. These differences, he asserted, emphasize “the difficulty to generalize the gap between calendar age and biological age.”