In a large study of older male veterans with type 2 diabetes and dementia, about half had HbA1c levels below 7%, even though guidelines caution against such tight glycemic control in this type of patient population.
Moreover, three-quarters of the patients with tight glycemic control were receiving sulfonylureas and/or insulin, medications that are known to cause hypoglycemia.
This study of more than 15,000 community-dwelling veterans was published online January 15 in Diabetes Care.
"Historically, there has been such an emphasis on tight control for younger patients — appropriately so — that this older, vulnerable group has been overlooked," lead author Dr Carolyn T Thorpe (Veterans Affairs Pittsburgh Healthcare System, Pennsylvania) told Medscape Medical News.
However, this study identified "a high rate of intense treatment of diabetes in older patients with comorbid dementia, potentially placing them at elevated risk for hypoglycemia and serious adverse events," she and her colleagues write. "Equally disconcerting is the high frequency of use of medications known to cause hypoglycemia."
Thus, clinicians "who care for older patients with diabetes who have dementia should review their glycemic targets and medications and consider relaxing the glycemic targets to moderate levels, maybe an HbA1c of 7% to 9%, and [replacing] sulfonylureas and insulin with agents that have a lower risk of hypoglycemia," Dr Thorpe said.
There is a "compelling need for the development of quality initiatives to encourage review of glycemic targets and antidiabetic medications in this rapidly growing group of patients, especially those aged > 75 and those with weight loss," the researchers conclude.
Changing Medication Needs in Diabetes with Dementia
Older patients with type 2 diabetes may have weight loss, reduced appetite, poor eating habits, and difficulty following therapy regimens, making them more prone to hypoglycemia, and they may not live long enough to reap the potential long-term benefits of tight glycemic control, Dr Thorpe and colleagues explain in their paper.
The 2003 US Departments of Veterans Affairs/Department of Defense (VA/DoD) guidelines recommend an HbA1c target of less than 7% only for diabetic patients expected to live at least 10 years and who have mild or no microvascular complications. The American Diabetes Association and the American Geriatrics Society (AGS) subsequently adopted similar recommendations.
And in 2013, the AGS specifically advised against using the sulfonylureas glyburide and chlorpropamide in patients aged 65 and older.
However, little is known about tight glycemic control and the use of insulin and sulfonylurea in older patients with type 2 diabetes and dementia.
To investigate this, Dr Thorpe and colleagues identified 15,880 community-dwelling veterans who were 65 or older in 2008 to 2009 and diagnosed with type 2 diabetes (or receiving an oral antidiabetic medication) and Alzheimer's disease or other dementia (or receiving medication for this).
Almost all patients (99%) were men, and 80% were non-Hispanic white. About half (55%) were 75 to 84 years old, and 21% were 85 and older. Most (81%) had hypertension, and 71% had documented dementia.
Frequent Unwarranted Tight Glycemic Control
Over half of the patients (52%) had tight glycemic control (HbA1c < 7%; mean, 6.3%), and over a third (36%) had moderate glycemic control (HbA1c 7% to <9%; mean, 7.5%). Few (7%) had poorly controlled glycemia (HbA1c > 9%; mean, 9.8%), and 5% did not have any reported HbA1c values.
Sulfonylureas were the most commonly prescribed antidiabetic (56% of patients), followed by metformin (41%) and insulin (35%). Few patients received thiazolidinediones (5.2%) or alpha-glucosidase inhibitors (1%). Meglitinides, dipeptidyl peptidase-4 (DPP-4) inhibitors, amylin analogs, and glucagonlike peptide-1 (GLP-1) receptor agonists were each used very rarely (< 1% of the sample).
Overall, 47% of patients were taking a sulfonylurea and no insulin; 26% were taking insulin and no sulfonylurea; and 9% were taking both agents. Among patients with tightly controlled glycemic levels, 75% were taking these agents.
Patients who had weight loss, chronic lung disease, or deficiency anemias or were 75 or older were more likely to have tight glycemic control, whereas obesity was protective.
Patients who were 75 or older; male; black; had congestive heart failure, peripheral vascular disease, or renal failure; or had been hospitalized or had spent time in a nursing home during the study year were more likely to be using sulfonylureas and/or insulin (and thus be at increased risk for hypoglycemia).
The researchers acknowledge that study limitations include a lack of data on actual hypoglycemic events, drug dose, patients' functional status, and whether patients received help from caregivers.
Although this research was conducted in a population of male veterans, another recent study in a population of older men and women who were not veterans "also showed that older adults who were in very poor health still tended to have very tightly controlled glycemia…and [high use] of sulfonylurea and insulin," Dr Thorpe noted.
Since it is unlikely that clinical trials will be conducted to compare different antidiabetic agents in this population, well-designed observational studies to help guide prescribing choices are needed, she and her colleagues say.
In the meantime, since lightweight, sicker, older patients with diabetes and dementia may be able to control blood glucose with less intense or even no antidiabetic medication, clinicians need to "consider medication options with a lower hypoglycemic risk" and "use the minimally intensive regimen required to achieve moderate glycemic control levels," they conclude.
Thorpe receives funding from the VA Health Services Research & Development. The authors have reported no relevant financial relationships.
Diabetes Care. Published online January 15, 2015. Abstract
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Cite this: Glycemic Control Too Tight in Elderly Diabetics with Dementia - Medscape - Jan 22, 2015.
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