Thursday, March 10, 2005

Women's Health Study,low dose aspirin, revisted

In my March 8th blog I questioned whether the AHA asa guidelines were still appropriate in light of the WHS's less than positive findings regarding primary prevention of cardiovascular disease with aspirin. Overall, there was no reduction in heart attack risk.Table 1 in the NEJM article indicates that only 3.9% of study participants had a Framingham Risk Score of 10% or higher which is the AHA threshold for recommendation for aspirin. So most of the participants would not have been recommended aspirin according to AHA guidelines. 84 % of women had a risk score of less than 5 %. The finding of of no decrease in risk in a group of women the majority of which did not "need" asa according to AHA, if anything, tends to validate the AHA recommendations.The article's tabulations do not display the percentage of women with a Framingham risk from 6-10%, but 11.8 % were from 5.0 to 9.9, so somewhere around 10% would have been recommended aspirin according to the more proactive USPHS guidelines. A similar argument seems to apply to those guidelines.
My spin on this is that the WHS study should not invalidate the AHA guidelines.In younger women, whose risk profile is less than 5%, I believe they should be counseled that the WHS study did show a fairly small decrease in stroke risk but that would have to be balanced by the demonstrated increase in GI bleeding.

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