This is an interesting study in that it confirms the low incidence of strokes associated with atrial fibrillation as mentioned in other cited papers. But citing relative risk figures when the incidence of end points is in the 0.5 to 1.5% range is certainly misleading. It may be that the decreasing rate of stroke attributed to AF is more due to the increase in heart rate monitoring---i.e. increasing the denominator. Granted the studies are usually short term, but another possibility is that Afib may not be a significant risk factor for stroke after all. With the given evidence, I would opt for no anticoagulation.
Thanks! Regarding external validity: the study was done in southkorean patients. It might be an irrelevant question, but do they have the same stroke risk as other etnicities? Even if the study was randomized, there were southkoreans in both arms... Many people of East Asian descent experience a distinct physical reaction to alcohol for example...
There are still some people whose insurance doesn’t cover DOACs, which are still expensive, so they are stuck on warfarin and regular INR measurement. Maybe these people should have an even higher bar for being on anti coagulation. Nice article.
Great stuff in the concluding paragraphs, where the thinking doctor is the one who accepts it is the (informed) patient's preferences that should make the decision. But (it follows) that on algorithms you need to actively dislike/hate recommender algorithms (and guidelines), while not tthrowing predictor algorithms out with the bathwater.
I’m curious why the AF community doesn’t switch to “CHADSVA” instead of “CHADSVASc”. The “Sc” attributes an extra point to females. Yet that extra point is disregarded at the time of clinical decision. As in this trial, low risk was 1 in males and 2 in females. So being female did not alter risk stratification in any event.
My other clinical conundrum is with newly turned 65 year olds who scored zero previously. They turn 65….happy birthday…here’s a DOAC…go ahead open it! I realize this is the case with any situation that turns a continuous variable into a (false) dichotomy, but few others involve an inexorable march in one direction. And I’ve had multiple pts (they always seem to be engineers) who balk at this “logic”: “doc, yesterday I was fine but today I’m not? That makes no sense”. For these pts, I’ve actually used a biomarker ABC score from Uppsala University (validated in a Swedish population) that treats age as a continuous variable and adds biomarkers (hsTrop and NT BNP). I’m curious how others have handled this type of scenario.
Great point. I looked for some breakdown of study participants by age in Table 1 or subgroup analysis of event rates in participants age 65-74 and found nothing. It would have been enlightening to see data for this population who’s only qualifying non-AF intermediate risk factor is age. I’m a little perplexed as to how any participant age 75 to 80 would satisfy the second inclusion criteria of CHA2DS2-VASc score of 1 (male) or 2 (female).
Two year f/u is too short. In real practice decades of life must be protected. A 60-70 y.o. must be protected to age 80-90 (or longer). Extrapolate that low percentage of mostly minor strokes to 10-15 times as long as 2 years and the total number of strokes is not so low and the not so minor events are not so rare.
Further, my intuition is that the cumulative stroke incidence over time will be non linear, will accelerate. My reasoning is that new clot will build and grow on older mural clot, gaining thickness while both losing mechanical strength and protruding deeper into the flow of atrial blood.
I remember atrial fib patients with embolic stroke and embolic MI. When warfarin anticoagulation was became recommended for patients with atrial fibrillation I'd already been in clinical medicine more that 20 years and in private practice for 17. The ordeal of warfarin: chasing protimes with dose adjustments, overshoot bruising and bleeding and the thromboembolic events due to inadequate dosing, were significant vs. the dosing simplicity and the efficacy we now enjoy with direct acting oral medications. Let me pass this on to the current generation of physicians and urge that we don't regress based on a short 24 month study.
This is an interesting study in that it confirms the low incidence of strokes associated with atrial fibrillation as mentioned in other cited papers. But citing relative risk figures when the incidence of end points is in the 0.5 to 1.5% range is certainly misleading. It may be that the decreasing rate of stroke attributed to AF is more due to the increase in heart rate monitoring---i.e. increasing the denominator. Granted the studies are usually short term, but another possibility is that Afib may not be a significant risk factor for stroke after all. With the given evidence, I would opt for no anticoagulation.
Thanks! Regarding external validity: the study was done in southkorean patients. It might be an irrelevant question, but do they have the same stroke risk as other etnicities? Even if the study was randomized, there were southkoreans in both arms... Many people of East Asian descent experience a distinct physical reaction to alcohol for example...
There are still some people whose insurance doesn’t cover DOACs, which are still expensive, so they are stuck on warfarin and regular INR measurement. Maybe these people should have an even higher bar for being on anti coagulation. Nice article.
Great stuff in the concluding paragraphs, where the thinking doctor is the one who accepts it is the (informed) patient's preferences that should make the decision. But (it follows) that on algorithms you need to actively dislike/hate recommender algorithms (and guidelines), while not tthrowing predictor algorithms out with the bathwater.
I’m curious why the AF community doesn’t switch to “CHADSVA” instead of “CHADSVASc”. The “Sc” attributes an extra point to females. Yet that extra point is disregarded at the time of clinical decision. As in this trial, low risk was 1 in males and 2 in females. So being female did not alter risk stratification in any event.
My other clinical conundrum is with newly turned 65 year olds who scored zero previously. They turn 65….happy birthday…here’s a DOAC…go ahead open it! I realize this is the case with any situation that turns a continuous variable into a (false) dichotomy, but few others involve an inexorable march in one direction. And I’ve had multiple pts (they always seem to be engineers) who balk at this “logic”: “doc, yesterday I was fine but today I’m not? That makes no sense”. For these pts, I’ve actually used a biomarker ABC score from Uppsala University (validated in a Swedish population) that treats age as a continuous variable and adds biomarkers (hsTrop and NT BNP). I’m curious how others have handled this type of scenario.
Great point. I looked for some breakdown of study participants by age in Table 1 or subgroup analysis of event rates in participants age 65-74 and found nothing. It would have been enlightening to see data for this population who’s only qualifying non-AF intermediate risk factor is age. I’m a little perplexed as to how any participant age 75 to 80 would satisfy the second inclusion criteria of CHA2DS2-VASc score of 1 (male) or 2 (female).
Interesting. I didn’t notice that. You’re right, age 75 should get you 2 points regardless of gender. Not sure how such patients would be included.
You didnt mention external validity and extrapolating findings from a South Korean population to a Western one?
Two year f/u is too short. In real practice decades of life must be protected. A 60-70 y.o. must be protected to age 80-90 (or longer). Extrapolate that low percentage of mostly minor strokes to 10-15 times as long as 2 years and the total number of strokes is not so low and the not so minor events are not so rare.
Further, my intuition is that the cumulative stroke incidence over time will be non linear, will accelerate. My reasoning is that new clot will build and grow on older mural clot, gaining thickness while both losing mechanical strength and protruding deeper into the flow of atrial blood.
I remember atrial fib patients with embolic stroke and embolic MI. When warfarin anticoagulation was became recommended for patients with atrial fibrillation I'd already been in clinical medicine more that 20 years and in private practice for 17. The ordeal of warfarin: chasing protimes with dose adjustments, overshoot bruising and bleeding and the thromboembolic events due to inadequate dosing, were significant vs. the dosing simplicity and the efficacy we now enjoy with direct acting oral medications. Let me pass this on to the current generation of physicians and urge that we don't regress based on a short 24 month study.
I very much appreciate your perspective!