Aspirin No Help for Stroke Outcomes
Low-dose aspirin might help ward off transient ischemic attacks (TIAs), but it didn't reduce overall incidence of stroke or improve outcomes following a stroke, an analysis of the Women's Health Study showed.There was no significant difference in total stroke incidence between women randomized to 100 mg of aspirin every other day and those randomized to placebo (OR=0.86, 95% CI 0.72 to 1.04), according to Pamela M. Rist, ScD, of Brigham and Women's Hospital in Boston, and colleagues.
Nor was the use of aspirin associated with significantly better functional outcomes in terms of total stroke, ischemic stroke, or hemorrhagic stroke (although outcomes tended to be worse for hemorrhagic stroke), they reported in the February issue of Stroke: Journal of the American Heart Association.
The odds ratios for experiencing a modified Rankin score (mRs) of 2-3, for example, were 0.94 for total stroke and 0.90 for ischemic stroke, but 1.66 for hemorrhagic stroke (all nonsignificant).
For an mRs of 4-6, the odds ratios were 0.94 for total stroke and 0.63 for ischemic stroke, but 1.47 for hemorrhagic stroke (all nonsignificant).
The fact that there was no benefit for aspirin for total stroke incidence is was most likely due to a nonsignificant increase in hemorrhagic stroke (OR=1.30, 95% CI 0.86 to 1.97), the authors wrote. Those taking aspirin did have a significantly decreased risk for TIA (OR=0.77, 95% CI 0.63 to 0.94) and a significant reduction in ischemic stroke (OR 0.90, 95% CI 0.65 to 0.98).
"This underscores the importance of using primary prevention methods, for example, aspirin or blood pressure-lowering treatment to reduce stroke incidence and its associated morbidity," Rist and colleagues wrote.
They also noted the importance of reducing "the morbidity burden" in women because they tend to have "worse functional outcomes after stroke compared with men."
Although aspirin has been validated as a means to prevent ischemic stroke in women, its impact on stroke morbidity is less well known.
However, an observed lower risk of TIA associated with aspirin in a previous analysis of the Women's Health Study might translate into a reduction of the "risk of stroke with a mild functional impairment," they said.
To accumulate more evidence for aspirin's effect on outcomes, Rist and colleagues analyzed participants from the Women's Health Study who had reported a stroke or TIA in the preceding year: 460 confirmed strokes (366 ischemic, 90 hemorrhagic, and four unknown), and 405 confirmed TIAs. Mean follow-up was 10 years. They compared stroke patients against study participants who had not reported a stroke.
The original Women's Health Study randomized nearly 40,000 healthy female healthcare professionals to receive 600 IU vitamin E or placebo, and low-dose aspirin or placebo on alternate days. The primary endpoint was cardiovascular disease or cancer.
The results, reported in 2005, showed vitamin E supplements did not protect women against heart attacks and stroke, nor did the vitamin have an effect on total cancer or the most common cancers in women -- breast, lung, and colon cancers, according to the study published July 6 in the Journal of the American Medical Association.
A subanalysis of the Women's Health study last year concluded that vitamin E was no help in preventing heart failure.
There was some functional benefit to those taking aspirin who did not smoke compared with placebo nonsmokers, but only in reducing TIA (OR 0.71, 95% CI 0.58 to 0.89) and having an mRs of 0-1 (OR 0.67, 95% CI 0.43 to 0.93).
"Whereas randomized assignment to 100 mg of aspirin every other day may reduce the risk of ischemic cerebral vascular events, especially TIA, we did not observe differential effects on functional outcomes from stroke," Rist and colleagues concluded.
Researchers did not have information on pre-stroke disability, and the results may not be generalizable to men, they said.
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