Choosing blood thinners for Atrial Fibrillation–a great summary

YES – I agree that Dr. Seth Bilazarian DOES give a nice presentation – and has come up with a handy acronym of “CRABI” for assisting in decision to user warfarin vs one of the newer blood thinners. I do think of him (as I think of you) as a very high integrity excellent clinician who truly wants to do the best for his patients.

That said – “lower risk of stroke” was presented in Dr. Bilazarian’s presentation in a “slam-dunk” fashion – whereas in my view it is anything but. “Slam-dunk” is what the manufacturers have put their billions of dollars into – in the hope of encouraging marketing of their product.

My interpretation of the literature is different and more guarded. The ARISTOTLE Trial (NEJM 365:981,2011) was promoted as showing apixaban to be more effective than warfarin in preventing stroke, systemic embolism, bleeding and mortality. BUT – to get those results to achieve statistical significance – they needed no less than 1000 sites to get their 18,000 patients – with numbers like reduction in stroke from 5.04% with coumadin to 4.49% with apixaban. Yes – that’s a relative 10% improvement – but a NNT (Number-Needed-to-Treat) ~ 200 patients in order to benefit one. Similar small statistially significant differences were found in the other parameters stated, all of which sound much better with relative percentage reduction numbers than when absolute numbers of patients over the denominator of total patients in this study are used ….

This is THE BEST that it is going to get: i) manufacturer-supported study; ii) cards stacked in favor of apixaban (patients with renal insufficiency Cr <25 excluded) – AND – patients therapeutic on warfarin only 66% of the time (would seem excess bleeding clearly faciliated when warfarin is supratherapeutic – as often occurred in this manufacturer study …. ).

I am NOT saying warfarin is wonderful – because it is not. Credit to Dr. Bilazarian because he does acknowledge issues of cost, and also favors continuing warfarin in patients doing well on that drug, those with renal problems, and those who don't want to be "early adaptors". BUT – Isn't this scenario familiar with "great results" in a manufacturer-supported study initially, only to see the blemishes come out one-by-one several billion-dollars-spent later after a period of use … – and to me, results in Aristotle – while positive, are anything but "great" given small absolute number reductions, huge cost, GI upset, no monitoring (as a disadvantage), need for compliance given shorter-duration-of-action with no-way-to-monitor-if-patient-is-taking-the-drug – plus lack of reversibility.

I DO think the new blood thinners offer certain advantages – and for some patients they are a better choice than coumadin. THAT SAID – overpromotion and "slam-dunk-appearance" of "increased efficacy" makes me highly suspicious of the maker of the drug …