study published online two weeks ago in Archives of Internal Medicine , the authors performed a meta-analysis of eight randomized controlled trials involving 32,053 patients w/atrial fibrillation followed for 55,789 patient-years (11-32 months) of warfarin use. Average age was 70-71 years old in most of the studies w/one study averaging 81 years old. Men comprised approximately two thirds of the participants. Average CHADS2 score was 2+ when calculated. And while multiple studies have demonstrated that atrial fibrillation increases the risk of ischemic stroke by 5 fold, judicious use of warfarin can decrease this elevated risk by 67%, down to an annual incidence of 1.66% in this meta-analysis w/major bleeding events varying from 1.4-3.4% depending upon definition of "major". More importantly, this meta-analysis confirmed the increase risk of stroke in the truly elderly (2.27%), female (2.12%) patients w/prior history of stroke (2.64%).So here's the good news: in a
Which then raises the question why aren't all qualified (high enough risk) patients w/atrial fibrillation given warfarin? As physicians, we use excuses like limited life expectancy, dementia, fall risk increasing the potential for hemorrhage. We also cite a history of gastrointestinal bleeding, history of hemorrhagic stroke, and history of other non-central nervous system bleeding as reasons to preclude warfarin use. And of course, we also claim (potential) drug-drug interactions, concerns for adherence, and requirements for regular testing as reasons to explain our reticence.
This could certainly go a long ways to explain our low use of warfarin, ranging from 17-57%, in patients at high risk for stroke but low risk for bleeding events, except that this was from a meta-analysis of 22 studies published last week in BMC Geriatrics involving patients institutionalized in long-term care facilities where one would hope that fall risk might be a bit less under supervision, medication adherence would be higher, and regular testing easier to obtain. So while it may be easy to exhort from the bully pulpit, I would encourage my colleagues to use the above calculators and think long & hard about using a proven therapy to prevent such a devastating event as a stroke in high risk patients, rather than fall prey to the typical excuses