Tuesday, April 10, 2012

Atrial Fibrillation & Stroke Prevention in Long-Term Care

Life is full of risk. We attempt to mitigate risk while enjoying life to its fullest.  While most decisions are made subconsciously, some require a focused risk:benefit analysis to determine whether to choose what's behind Door A or Door B.  As I noted in yesterday's post regarding atrial fibrillation, we use CHADS2, CHA2DS2-VASc and HAS-BLED to balance risk of ischemic/embolic stroke vs risk of hemorrhagic event, typically a gastrointestinal bleed or a hemorrhage stroke.  Stroke vs stroke.  Would you rather have the equivalent of a clogged pipe or a burst pipe in your house?

So here's the good news:  in a 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%).

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



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