Thursday, June 7, 2012

Baby Aspirin is a Double-Edged Sword

You see it all the time in advertising.  It's 100% natural, implying it's better.  It's all organic, implying it's safe.  Or you look on the grocery store or drugstore shelf and think to yourself, they're selling it, so the Food & Drug Administration must have given its blessing.  Wrong, wrong, wrong.  Have we forgotten all the recent recalls & alerts?  And let's not forget that there is no legal mandate for dietary supplement manufacturers to prove safety & efficacy of their miraculous claims as long as they display the FDA's disclaimer.

How many analogies do I need to employ?  There is no free lunch.  All medications & supplements can be likened to a double-edged sword with the ability to heal & to harm.  Don't take any medication unless the potential benefit is worth the potential risk.  Most importantly, take the medication as directed.  If you notice something out of the ordinary, notify the prescribing provider immediately.

But sometimes, the calculus isn't so easy to determine.  We've become numb to baby aspirin.  We're used to hearing "take one baby aspirin daily" without any mention of who should take it for what purpose and at what potential harms.  As I noted recently, aspirin appears to prevent heart heart attacks in men and strokes in women.  But in a population cohort study published yesterday in JAMA, the authors concluded that daily use of low-dose, baby aspirin increased risk of major bleeding, both gastrointestinal and intracerebral, by 55% compared to those who did not take aspirin.

In the case-control analysis, the authors followed for close to 6 years 186,425 Italian men (47%) & women (53%), average age 69yo, with & without diabetes, who were newly started on said low-dose, baby aspirin and compared them to 186,425 controls matched for the usual variables aside from aspirin use.  Rate of major hemorrhagic events was 5.58 per 1,000 patient-years in those who took aspirin, compared to 3.60 per 1,000 patient-years in those who did not take aspirin.

So what are we to make of this new data?  The editorialists remind us that there is a difference between secondary prevention (where benefit exceeds risk) vs primary prevention (where the balance is not so clear).    In secondary prevention (known cardiovascular disease), treating 40 persons w/aspirin prevents one thrombotic event while 240 are needed to be treated before causing a hemorrhagic event.  In primary prevention, we would need to treat 1,430 patients w/aspirin to prevent one thrombotic event while 2,500 need to be treated before causing a similar hemorrhagic event.  Clearly who we treat makes a difference.  So think twice before reaching for that daily aspirin.  Are you taking it because you have known heart disease or are you hoping to prevent a heart attack or stroke while placing you at greater risk for bleeding out?  As always, choose wisely!

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