Aspirin for primary prevention of CVD is an ongoing controversy for more than 2 decades. Please note, the controversy is not in the competence of Aspirin to prevent cardiovascular event, but in the potential risk of GI bleed and whether that risk is worth taking. Secondary prevention has no such issues as the benefits easily outweigh the potential bleeding risk .
Male vs female
There is a “gender” and “age” difference in the ability of Aspirin to prevent vascular events.Aspirin primarily prevents MI in men(>45) and stroke in women(>55) (Funny it may look, that’s what data says!)
Hence, the target age group for aspirin is between 45/55 to 80 years. (Up to 45 and beyond 80 it has no role .Beyond 80 , risk of hemorrhagic stroke is significant )
Diabetic vs non diabetic
Many believe all diabetics should straightway get Aspirin as it was considered CAD equivalent.Its not acceptable to all. . American diabetic association has risk stratified DM and advice Aspirin only in high / Intermediate risk.Look for Key word ie “Net benefit“ (Ref 2)
Why so much confusion ? and What can be the conclusion ?
The confusion is because each scientific body like AHA, ESC, ACCP, ADA ,USPSTF have their own inference and the presence of too many risk assessment tools adds further dizziness .(SCORE /FRAMINGHAM, etc). It tempts me to say ignore all these and use cortical sense !
Fortunately ,we do have some clarity as there is a common theme in all these advisories .Aspirin is indeed a wonder drug and able to block the platelets to prevent acute thrombus formation in the critical circulations.(FDA doesn’t seem to agree with this , How can a cheap generic do that job so effectively ? Let the Bayer fight ! )
It seems reasonable to conclude
All men and women between 45/55 to 80 years should get Aspirin (81mg /day or 325mg alternate days ) if there is at least one or two CVD risk factors provided there is no major bleeding risk .
Ongoing studies on primary prevention with Aspirin
ASCEND: A Study of Cardiovascular Events in Diabetes; or with diabetes taking a statin
ENVIS-ion (Aspirin for the Prevention of Cognitive Decline in the Elderly )
ASPREE (Aspirin in Reducing Events in the Elderly)
These studies are expected to bring more data (and be ready for more confusion!)
Can we use Clopidogrel for primary prevention if a person is intolerant to Aspirin ?
Logic may say yes.As of now it can not be advised.
2.Pignone M., Alberts M.J., Colwell J.A., et al; Aspirin for primary prevention of cardiovascular events in people with diabetes: a position statement of the American Diabetes Association, a scientific statement of the American Heart Association, and an expert consensus document of the American College of Cardiology Foundation. Circulation. 2010;121:2694-2701