I thought I understood stroke risk from AF until I was about to explain to my husband how CHADsVASC and HASBLED scores will be used during his consultation with a cardiologist.
Am I correct that the scores present a cumulative risk for each year in patients who are not taking any anticoagulant? My husband's CHADsVASC score is 3, representing a 3.2% stroke risk per annum, so does it really mean that the risk would increase by 3.2% each year if his health remains the same?
I'm overthinking this and don't want to get it wrong.
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Finvola
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I think that the risk is of a stroke within the next 10 years. The figure of 3.2% increase in risk is therefore not compounded annually. If it did then the risk over 10 years would be 37%.
That's what is giving me pause in what I had originally always thought -
year one - 3.2, year two - 6.4, year three - 9.6 and so on. It says in all the literature I can find that the risk is annual so I have assumed cumulative.
My understanding is that the % risk increases for each and every year, yes.
However, calculations done on this basis is about what is called ‘herd statistics’ and therefore this can only ever be, at best, an inaccurate estimate to be applied to an individual risk, based on statistics of general population.
My understanding is that CHADS has more or less been replaced by QRisk. My CHADS score is 4 but my QRisk is something like 28% of having a heart attack or stroke in the next 10 years. In 10 years I will be in my mid 80’s.
QRisk may sound high but as I don’t have any risk factors other than AF it is also based on age and gender, postcode and family history and height and weight.
Statistics cannot predict what will happen to you but they can indicate a risk profile on which a decision can be made.
I try not to get too hung up about statistics but having had a TIA when I stopped anticoagulants, pretty sure I will take for life - unless the risk of taking them suddenly outweighs the benefits.
I had a look at QRisk - did calculations for 81 year old and it gave 42% which isn't awfully far from the cumulative CHADs score of 37% for 10 years. Interesting that postcode is in the mix. I too am content to take Apixaban for life but my husband needs persuading - he has had only a few seconds of AF which he could feel and Kardia confirmed.
Yes, statistics are broadbrush - lies, damned lies, statistics and minutes of meetings is my mantra!
what you said about your TIA says it all there are so many people on here that wish they had had anti-coagulants before hand. I have been on mine since being diagnosed they were a little bit bothersome in the beginning, but not now, and I would not stop them for anything. Anyone who has had a stroke or knows someone who has should be able to tell you why you don’t stop taking them you make sure you take them . I have my AV node ablated I am still told I will be on them for life. I am aware they have new devices, but they are not for everyone and I am not a candidate. There may be many new things that come out in the future but if I stay the way, I am now I’ll be happy. The worst part about them in the beginning was the bruising because I seem to be extremely clumsy. I still have balance issues, and in the beginning I was falling down constantly, and would bruise something awful. Not sure what changed but I don’t bruise like I used to.
hearing from someone like you about your TIA is what people really need to read and pay attention to thanks for writing that
Can't add much to what has been said other than to mention HASBLED. It was explained a few years ago at conference that HASBLED did not contra CHADSVASC. It was an aid memoir of things to consider or address before prescribing anticoaguants as required by CHADSVASC. In other words a Hasbled score of 2 does not cancel out a similar Chadsvasc score.
Well I had no anti-co.agulant or any meds except B12 for deficiency B12.
I had an ischaemic stroke in Sept 2019 out of the blue @ am.
Diagnosed with Stroke and rapid persistent AF H.Rate. 4 days in hospital a carotid arteries scan which were squeaky clean the lass said "two for the price of one, I check your thyroid. Oops you have a shadow on your thyroid." The boss came into view. Transferred to local, I was rung to get my consent to have a biopsy. Of course I said yes. 4 months to a thyroidectomy.
Earlier that year my systollic seemed high and lopressor was given. But I was losing protein through my urine and stopped.
I was given a chads score of 1 last October because of a high blood pressure reading on the morning of my appointment with the cardiologist at 8.30 am after a stressful drive to my appointment. I took my home readings with me too and he said they are spot on but I am recommending anticoagulants for you to start after this reading of 155/ 92. I’m 56 active and working full time but do have occasional AFIB episodes, Iv had 3 PVI ablations, and do get weeks long bouts of ectopics which he wasn’t concerned about at all.! I’m not actually concerned about taking them because Iv read that even when in sinus rhythm someone with AFIB is more at risk of stroke. But I didn’t think a score of 1 would get me straight into the anticoagulants club.? I’m taking them and will continue to take them because no one wants a stroke.
"One recommendation suggests a 0 score for men or 1 score for women (no clinical risk factors) is “low” risk and may not require anticoagulation; a 1 score for men or 2 score for women is “low-moderate” risk and should consider antiplatelet or anticoagulation; and a score ≥2 for men or ≥3 for women is “moderate-high” risk and should otherwise be an anticoagulation candidate."
I asked this question a few months ago and the answer, counter intuitive though it seems is that the risk is cumulative. Though only a risk and not a certainty! I don’t claim to understand it myself. Here is that conversation.
Wouldn't each risk year be taken on the individual current facts/state of play of the comormorbidities at the time? There's no question on chads to ask how long a person has had AF.I wouldn't personally have thought it was cumulative, unless I'm missing something?
I understand it to be cumulative. However as mentioned above other 'individual lifestyle' factors play a part and I believe are understated purely because they are difficult to evaluate.
I am running a CHADS score of 1 until I reach 75 when, unless the goalposts are changed, my cardiologist is going to get more vocal on me starting ACs. Also a 'behind the curtain' reason of postponing ACs where appropriate for some is that it stops you relying on medication and drives you on to make more lifestyle changes to protect yourself.
This debate will run and run as without a parallel universe we will never know if we made the right decision 😖.
My understanding is that for the next period of 10 years, there is a 3.2% probability of a stroke in any one year. So the probability of one in the next 10 years is 32% (10 x 3.2%). Of course, in a large population, some may have one tomorrow, some not at all.
Thanks Speed - that was my understanding too but as I thought about it - and the stats on lightning striking the same place twice - I began to doubt my memory.
This is not how risk works. It 3.2% at any moment in time over the next 10 years. It's really not cumulative.
It is the same as the risk in dice of rolling a 6, which is one in six on each throw. If it was cumulative then if you hadn't thrown a 6 in the first 5 throws you definitely would on the sixth.
I suspect the 3.2% over a 10 year period is actually arrived from a 32% probability in 10 years but to provide an annual figure and make it more meaningful, they have divided the total by 10.
To be more specific, the way it actually works is to look at the chance of not having a stroke is 96.8% (presuming the 3.2% figure is the actual %).
The probability of being stroke free after 10 years is therefore 96.8 to power of 10 which is 69.92%. This is as near as damn it to the 68% (by taking 100-3.2 x 10)
If the % is significantly higher than the 3.2% or over significantly longer than 10 years then these numbers will diverge quicker.
I really don't think that's how risk calculations are meant to be used, you've introduced a cumulative element that is just not there in the 3.2% figure.There is probably an increased risk as the years go by but that would be represented by an increase in the specific 3.2% figure not by any accumulation of 3.2% over a period.
I’m not quite sure but are these stats based on a person being in permanent AF? My first PAF episode was 31 years ago and I would experience one episode on average every 5 years until 2022. My Chad score is 1
I am not a statistician but intuitively I would understand that as meaning that if the risk each year is 3.2% then the risk over a ten year period is 32% . But, providing nothing else changes, the risk of a stroke in any one year is still 3.2% . So it's 3.2% for year 1 and it's still 3.2% for year 10. It's not the risk that increases the likelihood, its the length of time that you consider it over - so if you're looking at the risk over a one year period then that is always going to be much smaller than the risk over a five or ten year period.
That makes sense Wilkie. Unfortunately, other explanations make sense too but yours is the best explanation for my understanding. My husband is/was an engineer, so I'm expecting a long, complicated dialogue when I introduce the subject to him. 🙂
Noooooo. If you role a dice the chance of it landing on a 6 the first time is 16.67%. On the second role it's still 16.67% not 33.33% and not 50% on the next throw. The chance resets every role of the dice.
For a stroke with Afib the chance resets every day, if not every second. It does not accumulate towards inevitability. No risk does.
If you look at it from the view of not landing on a 6. The chance each time is 5/6 (83.3333%). On your first throw, you have an 83% chance of not landing on a 6. If you have not landed on a 6, on throw 2, you still have an 83.33% chance again of not landing on a 6, so a 69% (83.33% x 83.33%) chance of not having landed on a 6 in 2 consecutive throws. Extrapolate this for 6 throws and you get a 33% (83.33% x 83.33% x 83.33% x 83.33% x 83.33% x 83.33%) probability that in 6 consecutive throws, you will not have thrown a 6.
The same principle applies to the stroke risk and after 10 lots of 96.8%, you get a 69 % chance of not having had a stroke if your in year risk is 3.2%
Think that's what I said ..the chance of a stroke any one year is still 3.2%. To use your dice analogy the chance that you will throw a 6 increases the more times you throw the dice. So the chance of throwing a six if you throw the dice once is lower than the chance of throwing a six is if you throw the dice many times. The more often that you throw the dice the higher the likelihood that one of those throws will be a six. Same with the stroke risk, the chance of having a stroke in the next year will be lower than the chance of having a stroke in the next decade.
After 7 years of infrequent AFIB I suffered a mild stroke a day after an AFIB episode. Hindsight is 20/20 but I sure wish I was on a blood thinner before
I was forewarned by two sisters having strokes in their mid sixties, before they knew they had AFib. Once I was diagnosed, I was very keen to take those anticoagulants! Though I was told that I wouldn’t have been offered them if I had been under 65 with a score of just 1 at that point.
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