Statins

[Mike Islander]

You do realize 1-1.3% is up to 60% greater risk than 0.8%?

Your numbers show that 3 is significantly different risk than 0 on CAC. He has been telling you the fact that someone has a 3 shows some calcification. The number of those people that then proceed to have CAD morbidity is real. Also, 10 year risk is short term when looking at a 30 or 40 year old man. We don’t know what that risk is in 30-40 years, but we can infer at simple extrapolation of 10 year risk that it’s 4-5%, and most would infer that it would be much higher than that. A relatively safe drug that has proven to reduce that risk is perfectly justifiable.

I want to be respectful, but I'm actually disappointed and a bit pissed off at your replies. Most charitably, you demonstrate why doctors sometimes recommend stuff based on a poor understanding of what numbers actually mean. It's a good demonstration of doubling down instead of admitting you were wrong. It's also a great demonstration of moving goalposts instead of just addressing my actual statements. Let's talk about where we disagree.

Absolute risk is what matters, not relative risk. It's five extra events per 1,000 people in 10 years (13 insead of 8). That's tiny! How about NNT? The NNT for CAC = 1-10 is 70-90. What is it for 0? 80-100. Almost meaningless difference.

EXAMPLE OF ABSOLUTE VERSUS RELATIVE RISK: If you have a 0.01% chance of dunking a basketball and I have a 0.02% chance, I’m technically 100% more likely to dunk on you. But in absolute terms, that’s just one extra dunk in ten thousand tries. Both of us are functionally not dunking that ball.”

If you linearize the log of the CAC number, which is the curve that is used for MESA risk versus CAC, there are about 8 per 1000 individuals in 10 years for CAC = 0 and 13 per 1000 for CAC = 3. It's actually more of a hockey stick cuve around CAC = 10 or less, so it's even less risk than the straight line shows.


Your risk over time position is flawed. It's irresponsible to extrapolate 40 years out when you can actually measure the disease on demand. Every time you retake the CAC, the timeline RESETS. If I get a CAC = 3 in five years (or even a lower CAC, since a 3 is on the same level as noise in the CAC test), my 10 year risk starts all over again from that value. You seem to be (and correct me if I'm wrong) advocating for treating someone for decades based on a 30-40 year timeline. If not, I have no idea what you are talking about. Do you think everyone should just take statins and be done with it? That's not supported by the data, nor by a CAC = 3.

 

[omicron1792]

This demonstrates why doctors sometimes recommend stuff based on a poor understanding of what numbers actually mean.

Absolute risk is what matters, not relative risk. It's five extra events per 1,000 people in 10 years. That's tiny! The NNT for even CAC = 10 is 70-90. What is it for 0? 80-100. Almost meaningless difference.

EXAMPLE OF ABSOLUTE VERSUS RELATIVE RISK: If you have a 0.01% chance of dunking a basketball and I have a 0.02% chance, I’m technically 100% more likely to dunk it. But in absolute terms, that’s still one extra dunk in ten thousand tries. Both of us are functionally not dunking that ball.”

If you linearize the log of the CAC number, which is the actual curve that fits risk versus CAC, there are about 8 per 1000 individuals in 10 years for CAC = 0 and 13 per 1000 for CAC = 3. It's actually more of a hockey stick around CAC = 10 or less, so it's even less critical that the straight line shows.
View attachment 947831

Your risk over time position is flawed. It's irresponsible to extrapolate 40 years out when you can actually measure the disease on demand. Every time you retake the CAC, the timeline RESETS. If I get a CAC = 3 in five years (or even a lower CAC, since a 3 is on the same level as noise in the CAC test), my 10 year risk starts all over again from that value. You seem to be (and correct me if I'm wrong) advocating for treating someone for decades based on a 30-40 year timeline. If not, I have no idea what you are talking about. Do you think everyone should just take statins and be done with it? That's not supported by the data, nor by a CAC = 3.

This is a great example of saying alot to say absolutely nothing.

I’m not talking about NNT. This isn’t to decide if using a statin is good for a group. This is to decide if an individual would benefit based on the known data. My 60% increase in risk is still valid, even based on your numbers.

 

[Mike Islander]

This is a great example of saying alot to say absolutely nothing.

I’m not talking about NNT. This isn’t to decide if using a statin is good for a group. This is to decide if an individual would benefit based on the known data. My 60% increase in risk is still valid, even based on your numbers.

If it's not needed for an individual with odds of 8 of 1000, why is it suddenly good for odds of 13 of 1000?

You said this “isn’t about groups, it’s about whether an individual benefits.” But that’s exactly what NNT quantifies.

All medical data come from groups — we can’t know which individual will benefit, only the probability that someone like you will.

NNT translates that group effect into individual odds:
If NNT = 100, each individual has a 1% chance of benefit.
If NNT = 20, each individual has a 5% chance.

So individual benefit is mathematically derived from group risk reduction.

That’s literally how personal risk is estimated in evidence-based medicine — your “individual benefit” is the inverse of the group’s absolute risk reduction.

I can explain it to you, but I can't understand it for you. I'm guessing most of our readers will understand my points...and my numbers.

 

[ddowning]

So the summary hit it. If you are zero (or close) your risk is low. If you are 300 (or close) you are at really high risk. So that takes care of about 25% of the people that take the test.

What about the 75% of people that fall in the middle? The data is all over the place.

That doesn’t even take into account non calcified vascular disease that doesn’t show up on CAC.

What do you ask for to test for non-calcified (redneck term...maybe) plaque? Is there something that will show up on?

 

[Marbles]

Sorry, very busy two days, I've not read all the other replies.

Why? Just why?

“A CAC score of 1–10 represents minimal calcified plaque and should not be considered diagnostic of coronary artery disease.”
— SCCT/AHA/ACC Expert Consensus, JACC Imaging, 2018"

1. A 3 CAC is near the measurable floor and treated the same as a 0 by most physicians. In fact it recently surveyed that 65% - 70% physicians treat it the exact same as a 0 regarding statin recommendations. You can look that one up on your own. Actually, you can look up both surveys.

2. A 3 does NOT equal a 3% risk over 10 years. Where did you get that number? MESA shows for a CAC of 1-10 that it indicates a 1-1.3% risk over 10 years, with a 0 score as high as 0.8%. Essentially no difference. And 3, if actually valid, is at the very bottom of that range.

3. CAC has a statistical variability of plus/minus 2%-5%. Up to HALF of those who get a second CAC after showing 1-10 score measure 0 on the next scan. My point is that we're in the noise here.

The test VERIFIED that I have no meaningful disease whatsoever. And that's a 5-10 year indicator. I like the verification.

The goal of my post was to WARN patients about what happened to me. As we've seen in the responses, many experienced the same thing...a PA/Doc putting them on statins without considering the one test that diagnosis actual disease. Remember, I had to self-educate before I realized that my artificially high clinical blood pressure alone put me over the threshold of "recommending a statin" using the blunt force ASCVD. I did the CAC to satisfy my own curiosity. A lifetime of CAC tests is about equal to ONE MAMMOGRAM SERIES worth of radiation. No measurable cancer risk. Thankfully it serendipitously showed the PA that she tried to "put me on a program of statins" without justification. I didn't throw it in her face. I simply asked for a CAC referral, and she interpreted the results. She knows what she did. Hopefully she learned from it. Hopefully docs who read but didn't post, and who aren't as caring or careful as you, also learned from this discussion. I do genuinely appreciate your input on this.

Thanks, I've enjoyed the discussion and it has gotten me to double check myself on a few things.

Old plaques calcify. To have a calcified plaque, it must have been present for some time. That or it is a false positive (which is possible) due to calcium in other structures or imaging artifact.

There is a difference between low risk (varified by your test) and no meaningful disease. A CAC cannot tell you the latter, even a CAC of zero. But, medicine deals in risk because we would cause a lot of harm demanding definitive testing in all cases and do very little good. To say no significant epicardial coronary disease you need an anatomic study, which would be a left heart cath angiogram or a CT angiogram of the coronaries with diagnostic quality images.

The reason this matters. If you have a clean cath within a reasonable time frame and tell me you have crushing chest pain and dyspnea on exertion I'm looking for a cause other than obstructive epicardial coronary disease. If you have a CAC of zero and tell me the same thing I'm ordering a stress test or going straight to an anatomic study like a cath.

What do you ask for to test for non-calcified (redneck term...maybe) plaque? Is there something that will show up on?

A Left heart cath (invasive procedure that is pretty safe, but does have some real risk of harm) or a coronary CTA.

No one should be doing caths just to lookie loo. Beyond the risk, they are quite expensive.

The CTA involves some complications. Usually they are not used on people over 65 as there is too much calcification and due to blooming artifact the images will not be diagnostic. Due to parallax error they are not great on large people. You also need to slow the heart down to about 50 beats a minute for good imaging, so the person needs to take beta blockers the night before and the morning of in most cases, which brings some risk. The contrast die can also cause kidney damage (rare) and allergic reactions (also rare) and the radiation dose is larger than for a calcium score.

 

[omicron1792]

What do you ask for to test for non-calcified (redneck term...maybe) plaque? Is there something that will show up on?

Only on a heart cath, an invasive test.