Do I Need a Calcium Score?

Calcium scores seem to be all the rage these days. Generally for good reason, but unfortunately I think many people misunderstand this test.

Why is that? How did we get here? Should you get one?

The main reason this is all so confusing is because we're trying to reduce understanding someone's cardiac risk to a radiology test. A calcium score is a CT scan (an advanced x-ray) of the heart.

It would be nice if that were possible, but unfortunately it's not.

Here are a few truths:

• Not everyone should have a calcium score.
• A normal calcium score doesn't mean you're necessarily risk free.
• A "bad" calcium score, under certain circumstances, is either redundant or unhelpful — and shouldn't make you feel any differently than you already did.

Let me explain: The calcium score can visualize calcified plaque. But cardiovascular risk is so much infinitely more complicated than that.

Atherosclerosis is a dynamic process which is based on numerous risk factors. Oh and by the way, the calcium score can't see arteries in other areas of your body (periphery, brain, organs, etc.).

The main purpose of a calcium score is to help further ascertain risk in intermediate risk patients to determine if further medications like statins or dramatic lifestyle changes are necessary to further reduce LDL cholesterol and risk in general. (I'm going to write another piece on statins and why they get so much hate, stay tuned.)

Put more clearly: if your risk factors are so minimal — or your risk factors are so high — the calcium score adds little value because we already know what to do.

An intermediate risk patient may be someone who is 50 years old with moderately high LDL (130-160), but maybe they have good blood pressure and no other risk factors, and they exercise regularly. They may be a good candidate for the calcium score if their calculated risk score is greater than 3% (the threshold for low risk) but less than 10%, the threshold for high risk. If they get a calcium score that was surprisingly higher than expected, then they really need to consider medication management to bring the LDL down to below 70. The reason for that specific number is that a significantly elevated calcium score effectively moves them up into the high risk category — and under 70 is the target that comes with it. It's virtually impossible to get an LDL that low on your own.

This is actually what the guidelines tell us to do. For patients in the borderline and intermediate range, a calcium score is recommended specifically when the decision about starting a statin genuinely isn't clear — not as a routine add-on. If the right move is already obvious, the scan isn't indicated.

And this cuts both ways, which is the part people miss. A calcium score of zero in that same patient is genuinely useful information. It's the single strongest negative marker we have in this area, and it can reasonably support holding off on medication and rechecking down the road.

If you're on the fence about a statin and would rather not take one, this is a test that can actually help you — in either direction.

That's the whole point of ordering it.

The purpose of the calcium score isn't simply "to get more information." And the reason this is the case is that, as I alluded to earlier, very high risk patients (those with numerous risk factors, or very high LDL cholesterol) should skip the calcium score and either go see a cardiologist, or just focus on reducing risk factors maximally, often with medications. There can be lots of soft plaque (which is invisible to x-rays). Also one's particular anatomy, combined with soft plaque, can result in a heart attack even in low calcium scores when the conditions are correct. Basically, if you're super high risk, a calcium score can give you a false sense of reassurance, and divert time and attention away from what is really important. Furthermore, if you have a calcium score and it is high — that should result in the exact same plan as before, which is getting risk factors maximally reduced immediately.

Very low risk patients are more likely to be harmed than helped by getting a calcium score because of radiation exposure (modest with modern scanners, but not zero) and also incidental findings discovered. I've had healthy young people getting annual calcium scores because their personal trainer told them to. I can not tell you how many patients of mine have been harmed by the work up for incidental findings from a calcium score.

There is an important exception here. Some people calculate out as low risk but have a real reason to look anyway — a parent or sibling with a heart attack in their 40s or 50s, an elevated Lp(a) (a genetic cholesterol particle that most people have never had checked, and that the risk calculators don't account for at all), or a chronic inflammatory condition like lupus or rheumatoid arthritis. The calculators simply don't capture any of that. If that describes you, a calcium score may well be reasonable even though your number looks reassuring. That's a conversation to have with your physician.

The way we determine whether you're low risk, intermediate risk, or high risk is by adding up all the main risk factors and coming up with an estimate. This is mostly based on blood pressure, cholesterol level, age, glucose levels, BMI, etc. There's a calculator you can use yourself called PREVENT online. That's actually a much more helpful place to start than ordering a calcium score.

We do not have a randomized trial showing that screening people with calcium scores reduces heart attacks or deaths.

The score predicts risk very well. Whether broadly using it to screen actually improves outcomes remains an open question — which is all the more reason to be thoughtful about who gets one.

I'm glad that people are getting more invested in their health these days — what's more important than your cardiovascular risk? But there seems to be a fundamental misunderstanding of the calcium score by both patients and doctors, and I try really hard to inform patients on exactly what and why we're ordering any given test. It's tempting to try to get a "concrete" result with a number to give us a "safe or unsafe" answer. If you've had a calcium score and don't know how to interpret it, or are curious about whether it's a good fit for you, please contact me.

Stephen