Dr. John Day, Cardiologist

Is Your Risk of an Atrial Fibrillation Stroke Going Down?

If you have atrial fibrillation (AFib), you may have heard about the CHADS-VASc score. It’s a scoring system doctors use to estimate your risk of having a stroke due to an atrial fibrillation blood clot. Each risk factor—such as congestive heart failure, high blood pressure, diabetes, or past strokes/TIAs—adds points to your score. Age is also a factor, with people over 65 getting one point and those over 75 getting two. Being female automatically adds one point.

According to current guidelines, men with a score of 2 or higher and women with a score of 3 or higher are recommended to take blood thinners for life. But does this really make sense? If women are already given an extra point just for their gender, why does their threshold for needing blood thinners also have to be higher? Wouldn’t it be simpler to just remove gender from the equation altogether and make it the same for men and women?

A new study of 129,789 people with newly diagnosed atrial fibrillation from Finland might help answer that question. Researchers looked at all AFib cases in Finland from 2007 to 2018 to determine whether the declining risk of AFib-related strokes was due to the increasing use of blood thinners or something else entirely. What they found was surprising.

Key Findings

Even after adjusting for blood thinner use, stroke rates in people with AFib decreased significantly over the 11-year study period—especially in women. Here’s what they found:

1. Women saw a 32% decrease in stroke risk that was independent of blood thinner use.

2. Men, on the other hand, had only a 7% decrease, which wasn’t statistically significant.

3. The biggest drop in stroke risk happened in those with higher CHADS-VASc scores. For example, patients with a score of 3 saw a 26% overall decrease in stroke risk. In patients with a CHADS-VASc score of 4, the overall incidence of a blood clot Afib stroke declined by 20%.

4. Age also played a role. In patients over 80, stroke rates dropped by 29% overall, with a 33% decrease in women and a 15% decrease in men.

What Does This All Mean?

While this is just one study, it’s an important piece of the puzzle. Scientific conclusions become much stronger when multiple studies all point in the same direction.

The findings suggest that AFib-related stroke risk may be decreasing over time, even as the population ages and accumulates more risk factors. This challenges the idea that women and older people with AFib inherently have a much higher stroke when it comes to AFib.

Could it be that previous studies overestimated the stroke risk in women and older people with AFib? Or is something else at play? With smartwatches and better awareness, many people are getting diagnosed with AFib earlier than ever before. Advancements in early detection and treatment may be reducing stroke risk across the board, making AFib less dangerous than it was two decades ago.

What’s Next?

A straightforward first step would be to remove gender from the atrial fibrillation risk assessment. The older studies that identified female gender as a higher stroke risk factor were likely flawed, and it may be time to discard this criterion. Simplifying the CHADS-VASc scoring system to CHADS-VA (by eliminating the “S” for sex so there is no distinction between men and women), with a universal cutoff score of 2 for lifelong blood thinners for both men and women, would make the process more consistent and easier to apply.

Secondly, is a score of 2 really the right threshold for a possible updated CHADS-VA system to determine when lifelong blood thinners are needed? Should the cutoff be 3 or even 4? This recent Finnish study certainly seems to suggest that the Afib stroke risk for people with higher CHADS-VA scores is also declining over time. Further studies are needed to determine whether the threshold should be adjusted to ensure that patients receive the optimal treatment.

Thirdly, should we still be giving people 2 points in the CHADS-VASc scoring system if their age is over 75? Given the findings of this study that older people with AFib may not be at as high a stroke risk as previously thought (or at least the stroke risks of older people with Afib may be declining over time), should the scoring system assign only 1 point for age over 75 instead of the current 2?

AFib, Strokes, and Blood Thinners

This Finnish new study is just one piece of the puzzle, and further research is necessary to validate these findings. But it does raise an important question: Should the way we determine who needs blood thinners in AFib be reconsidered? Personally, I believe this is the case but these things move very slowly. So, it could be years before we see any meaningful revisions to the Afib blood thinner guidelines.

For now, if you have AFib, you should continue following your doctor’s recommendations regarding stroke prevention and blood thinners. Additionally, future studies should reassess whether the criteria for lifelong blood thinners should be more flexible, as further research may help refine the appropriate cutoff.

While this study is just one piece of the puzzle, it highlights the need to continually reassess medical guidelines based on new evidence. Future research should refine stroke prevention strategies to ensure that recommendations are both effective and evidence-based.

Disclaimer

The information provided in this article is for educational and informational purposes only and is not intended as medical advice. Readers should not use this article as a substitute for professional medical advice, diagnosis, or treatment. Always consult your physician or a qualified healthcare provider before making any changes to your treatment plan, medications, or health regimen. The views expressed in this article are based on current studies and expert opinions but should not be interpreted as definitive medical guidance.

About the Blog Photo

This photo was taken today during our family’s amazing ski trip over the President’s Day weekend at Park City Mountain Resort in Park City, Utah. After a major snowstorm, we were treated to an epic powder day, making for unforgettable skiing conditions. The untouched snow beyond the resort’s boundary, just on the other side of the rope, was especially tempting to all the skiers enjoying the fresh powder.