Only one in three older Americans have their diabetes under control as measured by guidelines set by the American Diabetes Association, new Johns Hopkins Bloomberg School of Public Health research suggests.
Some argue that ADA guidelines may be too stringent for some older adults. But even using less stringent measures, the researchers found, there are still many older Americans whose diabetes is not well managed, a condition that can lead to multiple long-term health problems ranging from kidney disease to blindness.
In a report published in the July issue of Diabetes Care, the researchers also found serious racial disparities, primarily in women, in how well diabetes is being managed, with black women much less likely to have acceptable blood sugar, blood pressure and cholesterol levels than white women.
The findings suggest that there is a lot of work to be done to care for people with diabetes over the age of 65, a population universally eligible for government-funded health care through Medicare. But the research also raises questions about the value of broad guidelines for glucose and blood pressure control in older Americans considering that medications to lower blood sugar and blood pressure come with potentially serious side effects that may outweigh the benefits of pushing for lower sugar and blood pressure levels.
"This research gives us a good picture of diabetes control in older adults and gets us thinking about what it means that older Americans are not meeting clinical targets and how we should address this from a public health perspective," says study leader Elizabeth Selvin, PhD, MPH, a professor of epidemiology at the Bloomberg School. "There is tremendous debate about appropriate clinical targets for diabetes in older adults, particularly for glucose control. Are some older adults being over-treated? Are some being undertreated? These are questions for which we don't have answers."
For the study, Selvin and the team used data from the Atherosclerosis Risk in Communities Study (ARIC), which in 1987 began following a group of 15,792 middle-aged adults in communities in Maryland, North Carolina, Minnesota and Mississippi. Selvin's team focused on the 1,574 now-older participants with diabetes remaining in the group between 2011 and 2013 when they had their fifth study visit.
The researchers looked at three different measures key to good diabetes control - hemoglobin A1C (which measures blood glucose levels), blood pressure and LDL cholesterol. The American Diabetes Association guidelines call for hemoglobin A1C levels below seven percent, blood pressure under 140/90 mmHg and LDL cholesterol under 100 mg/dL. While 72 percent met the hemoglobin A1C level, 73 percent met blood pressure goals and 63 percent had good cholesterol levels, only 35 percent met all three targets.
When the target levels were raised to a less stringent level - hemoglobin A1C under eight percent, blood pressure under 150/90 mmHg and LDL cholesterol under 130 mg/dL - the results were better, but many still did not meet the targets. Ninety percent met the target for hemoglobin A1C, 87 percent for blood pressure and 86 percent for cholesterol. Yet only 68 percent had their diabetes well controlled by meeting all three targets.
One factor involved in poor diabetes control could be that older people with diabetes are more likely to be sick with other diseases on top of their diabetes and those other illnesses may need more immediate attention from doctors, says study co-author Christina M. Parrinello, PhD, MPH, who recently earned her doctorate from the Bloomberg School. Many of the complications associated with poor diabetes management - kidney disease, blindness and nerve damage - take a long time to appear, longer than the patient's life expectancy given other illnesses, she says.
If patients over 65 are over-treated - say, their blood pressure goes too low or their glucose levels drop too sharply - they are at risk of losing consciousness, falling and other medical problems.
"There is a question in this field of how much good we are doing as opposed to harm when we try to tightly control diabetes in older people, because the treatments are not benign in older adults," Parrinello says. "If the primary benefit of glucose control, for example, is to prevent kidney, eye and nerve damage - complications that take 10 to 20 years to develop - maybe it doesn't make sense to focus on glucose control in certain patients where diabetes may be the least of their concern."
More research is needed to determine what the best control targets are in an older population. The researchers say that each patient needs to be carefully considered individually. A 70-year-old with newly diagnosed diabetes and no other major illnesses should probably be treated differently than someone who is 70 but has long-standing diabetes and is struggling with other major health issues, yet guidelines often consider these two patients to be similar.
The researchers say more also needs to be understood about racial disparities in diabetes control, particularly with regard to women. The racial differences persisted even when the researchers accounted for factors such as income and education levels. White women were 58 percent more likely than black women to meet all three clinical targets.
"Prevalence of and Racial Disparities in Risk Factor Control in Older Adults with Diabetes: The Atherosclerosis Risk in Communities Study" was written by Christina M. Parrinello, Ina Rastegar, Job G. Godino, Michael Miedema, Kunihiro Matsushita and Elizabeth Selvin. Rastegar was a student at Baltimore Polytechnic Institute, a local high school, when she worked on the study. She came to the Bloomberg School as part of the Ingenuity Project, which aids promising Baltimore City students.
ARIC is carried out as a collaborative study supported by contracts with the National Institutes of Health's National Heart, Lung, and Blood Institute. This new study was supported by the National Institutes of Health's National Heart, Lung, and Blood Institute Cardiovascular Epidemiology Training Grant (T32-HL-007024); the National Institute on Aging Epidemiology and Biostatistics of Aging training grant (T32-AG-000247) and the National Institute of Diabetes and Digestive and Kidney Diseases (R01-DK-089174).