(RxWiki News) Women with a common abnormal heartbeat condition called atrial fibrillation are at a greater risk of stroke even if they take anticoagulants to lower their risk. This was especially true for women over the age of 75.
Researchers said the findings suggest that current anticoagulant therapy such as the commonly prescribed Coumadin (warfarin) may not be sufficient for preventing stroke in older women.
"Control high blood pressure to lower stroke risk."
Meytal Avgil Tsadok, PhD, of the McGill University Health Center in Canada, found that the stroke risk for women with atrial fibrillation was higher regardless of their risk profile or use of warfarin. One of the most concerning sex-based differences related to atrial fibrillation has been the increased risk of women suffering cardiovascular events, particularly stroke.
It had been previously suggested that the added risk in women, in part, stemmed from an underutilization of oral anticoagulants.
During the cohort study, 39,398 men and women over the age of 65 who were recently diagnosed with atrial fibrillation at a Canadian hospital between 1998 and 2007 were followed. Investigators used administrative hospital discharge data, and physician and prescription drug claims databases.
Women tended to be older upon hospital admission, with 74 percent older than age 75 as compared to 61 percent of men. Women also were more likely to have suffered from congestive heart failure, hypertension, diabetes, or have had a prior stroke or mini-stroke.
Women were slightly more likely to have been prescribed warfarin at a rate of 61 percent in women versus 58 percent in men. The proportion of warfarin prescriptions filled was 68 percent for both women and men, and compliance rates were similar among both genders.
Investigators found that 6 percent of women suffered strokes as compared to 4 percent of men. The difference was mostly driven by the higher stroke rates among patients over the age of 75.
However, women over the age of 75 were significantly more likely to have a stroke, regardless of whether they took warfarin. Researchers said women were 14 percent more likely to suffer a stroke, after adjustments were made for various factors.
They have not yet determined why women are more susceptible to stroke, though they suggested uncontrolled hypertension, genetics, hormones or psychosocial factors could play a role.
The study was published in the May 9 issue of the Journal of the American Medical Association.