As if there aren't enough people taking Plavix already ($6 billion in sales per year) researchers published a study today showing incremental benefit to adding plavix to aspirin in atrial fib patients deemed not candidates for coumadin. The issue is this: coumadin has long been shown to be superior to aspirin for preventing stroke in atrial fibrillation. Coumadin's bleeding risk is similar to asprin but only if properly managed in a compliant patient. In the real world it can be difficult to make sure people are taking coumadin correctly and many patients are deemed not to be candidates for coumadin. We are probably "treating the doctor" when we withhold coumadin from an elderly patient but I have seen enough mishaps from improperly managed coumadin that we are ok using caution. So the friendly folks at Sanofi-Aventis which makes Plavix funded a study showing what happens when these non-candidates for coumadin take Plavix in addition to their aspirin. Lo and behold there is a benefit with fewer strokes. There is substantially more bleeding and in my mind this probably invalidates the benefit seen in the study. The obvious question was overlooked by what I think to be a poor trial design. Here is the trial design they used: Asprin alone versus aspirin plus plavix Here is the trial design that I really want to know about: Coumadin versus aspirin plus plavix. If we accept that coumadin bleeding risk is about 1% per year then aspirin plus plavix looks to be more toxic than coumadin and probably no more effective than coumadin. This is the little secret of this article that they don't want you to figure out: probably many of these patients would be ok going on coumadin which is a lot cheaper than plavix. When you have a $6 billion dollar hammer every new indication looks like a nail. Thanks for nothing NEJM.