ARTICLE IN BRIEF
Investigators reported that each year of diabetes duration was linked with an absolute 3 percent increase in stroke risk, compared with the risk for non-diabetics.
SAN DIEGO—Diabetic patients who have had the disease for 10 years or more carry a more than three times greater risk of stroke than non-diabetics, and nearly twice the risk as those who have had diabetes up to five years, according to a Columbia University study presented here at the annual meeting of the American Neurological Association.
Researchers say that while it can be expected that the stroke risk will go up with longer duration of diabetes, this is the first time that the risk associated with duration has actually been measured among both men and women.
The findings are based on an analysis of data from the Northern Manhattan Study, begun in 1993, which has been monitoring health risk factors for 3,298 participants who had not suffered a stroke at baseline.
Diabetes was determined either by self-reported diagnosis, the use of anti-diabetic medication, or a fasting glucose of greater than 126 mg/dL.
Researchers found that people who had diabetes up to five years had a 70 percent higher risk of stroke than non-diabetics (95% CI = 1.1-2.7). Those with diabetes from five up to 10 years had an 80 percent higher risk of stroke than those without the disease (95% CI = 1.1-3.0). And people with diabetes 10 years or more had a three times greater risk of stroke than non-diabetics (95% CI = 2.4-4.5).
Overall, each year of diabetes duration was linked with an absolute 3 percent increase in stroke risk, compared with non-diabetics, however the relationship was non-linear, researchers found.
“It has a threshold — for those who have diabetes greater than 10 years, the risk triples,” said Julio R. Vieira, MD, MS, an epidemiologist at Columbia University who is also a resident in neurology.
The average age of the participants was 69 at baseline. At baseline, 717 (22 percent) of the subjects had diabetes. Among those who were not diabetic at baseline, 338 subjects (13 percent) reported developing new-onset diabetes. There were 244 ischemic strokes during follow-up, which averaged 13.3 years.
Researchers are continuing to follow the participants. The message, Dr. Vieira said, is that if we can control diabetes early on, we may not see the increased risk for stroke.
LIFESTYLE COMPLIANCE A FACTOR
Pratik Bhattacharya, MD, MPH, assistant professor in the Stroke Program at Wayne State University, said the study results might help reinforce patient compliance with suggested lifestyle changes for better control of diabetes.
He noted that compliance varies from population to population. “I'm from Detroit. I deal with an inner-city population who are often underinsured and it can get really difficult,” he said.
The study, he said, “gives us all the more reason to look for and treat diabetes.”
He said it was important, though, not to focus too much on the exact 10-year mark for the sharp increase in stroke risk.
“We don't know what the duration has been when we pick up diabetes,” he said. “The patients could have had it for a while. More than the timeline, for me, it increases the urgency to treat diabetes and achieve control as soon as possible.”
“To say to patients, when you” ve had diabetes for a significant amount of time, you might skyrocket your risk — I think thats the idea, the take-home message.”