Statins, heart disease, strokes, levothyroxine doses and liothyronine. A check on the logic

[helvella]

NICE CKS guidelines for prescribing statins to reduce risk of cardiovascular disease clearly point at the QRISK3 calculator.

The NICE CKS Guideline is here:

CVD risk assessment and management: Scenario: Management of people with an estimated risk of 10% or more

Last revised in September 2024

cks.nice.org.uk/topics/cvd-...

The QRISK3 calculator is here:

Welcome to the QRISK®3-2018 risk calculator qrisk.org

qrisk.org/index.php

Many here will be aware that thyroid treatment - both in guidelines and in practice - tends to refuse any treatment until TSH is quite high, keeps levothyroxine (LT4) doses lower than many like, refuses liothyronine (LT3), tends not to test FT4 and rarely tests FT3.

The argument is frequently based on claimed increased risks of stroke and heart failure in those with low TSH (often ignoring FT4 and FT3 entirely), or taking any LT3.

Yet the massively hyped QRISK3 calculator doesn’t ask ANYTHING about thyroid. The obvious inference being that thyroid has NO effect on heart failure and stroke risk. Otherwise, those responsible would surely have included a question about thyroid, wouldn’t they?

If high FT3 (whether endogenous of exogenous) is a risk factor, why has QRISK ignored it?

Similarly for high FT4, low TSH.

And there is much evidence that high TSH, low FT4 and/or FT3 are associated with heart disease/disorder.

Which set me thinking... Imagine someone who takes levothyroxine visiting their doctor.

D: Good morning. I’ve just run QRISK3 and it says: “Your risk of having a heart attack or stroke within the next 10 years is: 26.7%.” So I’d like you to take a statin to reduce that risk.

P: Is QRISK3 accurate?

D: Yes - it has been used since 2009 and it is extremely accurate.

P: OK. While you are prescribing a statin, could you also increase my levothyroxine dose? Actually, I’d really like to try liothyronine.

D: Sorry but your TSH is already near the bottom of the range. And if I prescribe more it will increase your risk of heart disease or stroke. And liothyronine is even worse so I simply will not prescribe it.

P: Ah right. How much does it increase the risk?

D: Sorry - but I don’t have the figures to hand but it is a very serious issue.

P: Hey - you’ve just persuaded me to take a statin because you can predict my risk using QRISK3. How about using that to see the effect of changing my levothyroxine dose or prescribing liothyronine.

D: QRISK3 doesn’t look at thyroid.

P: What? Not at all?

D: No.

P: Well that means one of two things. Either QRISK3 isn’t so wonderful because it ignores thyroid entirely.

D: No - QRISKS3 is still amazingly accurate.

P: Or thyroid hormone levels, high or low, simply do not affect my risk…

[Topsy33]

Helvella, I found myself smiling at this scenario. I had a vision of you, resplendent in a Barrister's wig and gown, with Doc in the dock!

[Judithdalston]

Love it!

[Reefseeker]

Thank you for this Helvella. It underlines my significant concerns around TSH and FT3 levels. My FT3 levels for the past 4 years have averaged 4, with the lab range minimum 3.3 and max of 6.8. The TSH over the same time has averaged 0.002. I am on combination T3/T4 treatment. It has been a constant battle to get the endocrinologist not to reduce my dose, as he is obsessed with the TSH. I think my FT3 is too low for me to feel healthy. He won't have it and tells me my heart and bone density are at risk. My recent bone density test came back fine. In the paper that showed the health risks of suppressed TSH, did they test FT3 levels, which surely are more important? And can anyone provide a link to the paper please?

[DippyDame]

To quote the late Dr John Midgley/ diogenes,

"For the moment mechanical thinking has traduced medical diagnosis."

I rest my case!

[humanbean]

This blog post from Dr Malcolm Kendrick is worth reading :

drmalcolmkendrick.org/2019/...

It doesn't mention thyroid but does mention qrisk3.

I searched Malcolm's blog site and found qrisk3 mentioned several times, if anyone is interested, although most of the mentions were almost identical to one another.

[DippyDame in reply to humanbean]

MK...a man who calls a spade a spade!

[helvella Administrator in reply to humanbean]

He has a recent blog on risk calculators. Ends up:

PREVENT is just another in a long line of useless risk calculators, designed to promote pharmaceutical interventions. They all overestimate risk because that way more people end up on drugs. They are not predictive, they are not scientific. In my opinion they should all be ignored.

brokenscience.org/risk-calc...

[helvella Administrator]

Thanks, HB.

I have little faith in such calculators.

The use of postcode is, in my view particularly odd. The implication being that moving house could be a good move. No information about how long you have been there. If you have just moved from one of the worst to one of the best (or vice versa), you completely wrong-foot it.

I was really trying to use it in reverse to justify T3!

But totally ignoring thyroid is madness.

[Regenallotment Ambassador]

That made me laugh! Gotcha!!

[Brightness14]

I have just printed it out, thank you for the information. Amazing thing is nearly everybody I know is either on or asked to go onto these Statins.

Wig and Gown sound good to go.

[AKatieD]

Great thought process

Malcolm Kendrick seems to offer similar when he rubbishes conventional medical opinion. Happy to prescribe ineffective SSRIanti- depressants without any testing on an individual hoping to make them feel better, but not happy to prescribe thyroid hormones if they make us feel better unless TSH supports, being a case in point.

[serenfach]

Computer says No - cough...

[Afaghieh]

Hi

I think it's also good to have a look at " FRAMINGHAM HEART STUDY "

[Seabird4]

Magic made my day

[Guineapiggy]

Also essential viewing on data manipulation

youtu.be/T3ldcRYadR4(Not working as expected?)

[ Edited by admin as the original link did not work. The links with "watch" in them can't work. Try right-click and Copy video URL. ]

[Guineapiggy in reply to Guineapiggy]

Can't seem to do it on a tablet. Will have to use the laptop!

[Radio2]

Thank you for this Helvella, it made me smile - but also is quite sad for us with thyroid issues.