Thyroid hormone treatment intensity linked to increased risk of cardiovascular mortality

[helvella]

Just how long can this go on?

Positively defining in terms of TSH alone. "… exogenous hyperthyroidism or hypothyroidism, which is having thyrotropin levels inappropriately below or above the normal range".

And then going to to suggest it is the thyrotropin level which is the cause? Without having even mentioned the actual thyroid hormones (except levothyroxine).

Thyroid hormone treatment intensity linked to increased risk of cardiovascular mortality

The findings highlight the importance of regular monitoring of thyroid function and prompt correction of over- and under-treatment with thyroid hormone to reduce patient harm.

Michigan Medicine

One synthetic thyroid hormone, levothyroxine, lands itself on the United State’s list of top three prescribed medications in the country over the last decade. Simultaneously, despite all efforts to reduce its prevalence, heart disease remains the leading cause of death in Americans, affecting nearly half of the population aged 20 years and older.

However, studies evaluating the association between the intensity of thyroid hormone treatment and heart disease-related death are scarce, according to University of Michigan Health endocrinologist and U-M Institute for Healthcare Policy and Innovation member Maria Papaleontiou, M.D.

In a study published in JAMA Network Open, Papaleontiou sought to evaluate the relationship between thyroid hormone treatment intensity and cardiovascular mortality in a retrospective cohort study of more than 705,000 U.S. veterans who received thyroid hormone therapy between 2004 and 2017.

The work from Papaleontiou’s team follows an observation that up to half of patients who receive thyroid hormone therapy have exogenous hyperthyroidism or hypothyroidism, which is having thyrotropin levels inappropriately below or above the normal range, respectively. Could the amount of thyrotropin abnormality outside the normal range be associated with increased risk of cardiovascular death?

labblog.uofmhealth.org/lab-...

[nellie237]

"Could the amount of thyrotropin abnormality outside the normal range be associated with increased risk of cardiovascular death?"

In my miniscule world I would say yes...

Six months before I had a heart attack in Dec 2012 my TSH had an odd spike of 6.33 (0.35 - 5,5), FT4 was 17.5 (9-22.7)...... no idea what FT3 would have been because I hadn't found this wonderful forum then. I'd also been under-medicated from 2007 - 2009, which I'm sure. didn't help.

"Without having even mentioned the actual thyroid hormones" I couldn't agree more, but sadly they're never going to spend the money on testing, even if it is false economy. 🤦‍♀️

[jimh111]

This study is consistent with others including this one doi.org/10.1210/jc.2009-1625 which I think is a good study. I haven’t read this latest study yet.

These are retrospective studies and so they can only look at TSH and fT4 because fT3 is rarely measured. Yet more reason why testing should include fT3.

Certainly a TSH outside its reference interval is associated with increased risk but there’s no excuse for not going further and identifying what profiles have greatest risk. i.e. which of TSH, fT3, fT4 are most relevant?

I’ve already posted that T4 appears to have a specific role in cardiac disease (and cancer) and hence argue that levothyroxine monotherapy should not be routinely used.

An important point to note is that the adjusted risk of a TSH above 5.0 is greater than that of a TSH below 0.1. So called ‘subclinical hypothyroidism’ is a cardiac risk factor. A bigger risk than a low TSH. Doctors never point this out.

[helvella in reply to jimh111]

These are retrospective studies and so they can only look at TSH and fT4 because fT3 is rarely measured. Yet more reason why testing should include fT3.

I so agree. The amount of research which is at the least blunted by lack of any sort of T3 result is enormous.

Far too much of the not doing T3 testing is based on assumption, indeed, poorly founded assumption.

Ironically, in terms of scientific logic, they needed to do T3 testing in many more situations and much higher numbers just in order to have conclusively proved that there is no point doing T3 testing. (Though I'm sure many here have test results which demonstrate that that would not be proved in any truly valid, large-scale research.)

(I refer to "T3" simply to allow that both TT3 and FT3 might have stories to tell.)

[nellie237 in reply to jimh111]

"Doctors never point this out" No, they don't, because unlike AF, it isn't urgent/doesn't require action/intervention................until it is/does.

[HashiFedUp]

I think that there are a multitude of other factors involved in cardio death… like being unhealthy. How on earth can a study of thyroid levels alone be valid. How many patients were obese for example?! I think the American lifestyle and diet are the causes of heart disease and not hypothyroidism!

[Sparklingsunshine in reply to HashiFedUp]

Hi

Well exactly, as well, as genes, exercise levels, smoking, drinking as well as Co morbidities like diabetes.

[DippyDame in reply to HashiFedUp]

I agree!

Simultaneously, despite all efforts to reduce its prevalence, heart disease remains the leading cause of death in Americans, affecting nearly half of the population aged 20 years and older.

If medical intervention has failed does that not then suggest lifestyle as a likely cause!

Are they trying to " point the finger" away from what seems obvious!!

[bantam12 in reply to DippyDame]

Agreed that for many lifestyle is a factor however for many of us with heart problems lifestyle doesn’t come into it.My husband died of heart problems, not genetic, wasn’t overweight, never smoked or drank in excess, and the same applies to me, the only issue we both had was thyroid disease.

[DippyDame in reply to bantam12]

Apologies if my comment sounded harsh I absolutely understand that, for some, lifestyle isn't a factor. These comments referred to US lifestyles.

I'm very sorry for your loss bantam12

My parents both died (relatively young) of heart problems when I was 29 and knew nothing of hypothyroidism. Both had had a healthy life style....but had never been tested for hypothyroidism. I'll never know if there was any connection.

But, looking back , I'm sure my mother had symptoms of undiagnosed hypothyroidism and I know that I inherited the Dio2 snp from both of them.

I was agreeing with HashiFedUp 's comment, "there are a multitude of other factors involved in cardio death...like being unhealthy".....but I realise it was perhaps in an insensitive manner. I'm sorry if I upset you.

[bantam12 in reply to DippyDame]

Absolutely no worries, I wasn’t upset at all, just putting another angle on the subject. Unfortunately many health problems are automatically blamed on lifestyle and Drs are often the first ones to jump to conclusions, as we well know ! Quite annoying that some who do lead a dodgy lifestyle doing all the wrong things seem to get away with it (I have a friend like that!) whereas those that are good often don’t 🤷‍♀️

[jjf255 in reply to HashiFedUp]

The other question I have is...does undiagnosed hypothyroidism or undertreated hypothyroidism, contribute to obesity and increase the risk of diabetes, high blood pressure ETC, which in turn contributes to heart disease?

[helvella in reply to jjf255]

It would appear entirely reasonable to suspect those of being mechanisms by which hypothyroidism contributes - though there might be other ways, as well.

[roukounasGK in reply to HashiFedUp]

I dont agree. Though indeed, the lifestyle is crucial, in order to present something which is considered a study (even more if it is published) you have to take into account these cases and eliminate them. In order to be clear, suppose that on the general population the prevalence of cardiac issues is 50% (i dont know if this is true its just a number i came up for the sake of example). So if you find something close to this percent within the thyroid population, it is safe to assume that the thyroid does not affect it, and its as you mentioned, i.e. its the lifestyle to blame.

If however you find that the prevalence of cardiac issues among the thyroid population is for example 90% it is very safe to assume that the thyroid issues and/or medication does affect the cardiac health of people.

In other words, it is a given that in order to publish a paper, such cases must bw taken into account and eliminated as much as possible.

[tattybogle]

Another fine example of how the game of chinese whispers goes on .. and on ..

turning *TSH into SH*T

jamanetwork.com/journals/ja...

The original paper that this article refers to includes fT4 measurements, not just TSH .

The original paper classes exogenous hyper as TSH below range AND fT4 above range.

"Exposures: Time-varying serum thyrotropin and FT4 levels (euthyroidism: thyrotropin level, 0.5-5.5 mIU/L; FT4 level, 0.7-1.9 ng/dL; exogenous hyperthyroidism: thyrotropin level, <0.5 mIU/L; FT4 level, >1.9 ng/dL; exogenous hypothyroidism: thyrotropin level, >5.5 mIU/L; FT4 level, <0.7 ng/dL)."

But then Michigan Medicine write about it , and totally fail to mention the part about fT4 being over range , and turn a reasonably interesting paper into just one more piece of 'TSH centric' bollocks .

There is an interesting letter attached to the 'comments' section for this paper:

"Intuitive conclusions from your invaluable data

Saeed Taheri, M.D. | NLMJ

The adjusted odds ratios in Table 2 suggest that exogenous hyperthyroidism may be more benign than hypothyroidism in the context of CVD mortality. Even the highest level of hyperthyroidism had a comparable mortality risk to that of the lowest hypothyroidism level, while all other comparisons favored exogenous hyperthyroidism in terms of lower CVD mortality versus hypothyroidism at any levels. This suggests wherever there is concerns of over- or under-treatment with thyroid hormones, it may be best to err on the side of over-treating the patient.

Also, with the extremely large and precise data you have, I think you have an incomprehensibly valuable opportunity to define normal thyrotropin ranges for specific subgroups of patients, analyzing if more stringent control towards lower or higher thyrotropin ranges are safer for the recipients of thyroid hormones with specific conditions, e.g. diabetes mellitus, hypertension, history of CVD, or age, sex and ethnic specific analyses. Another analysis that could be of high interest was to deferentially analyze the data for patients with initial hyperthyroidism who became hypothyroid as a consequence of treatment versus patients who had hypothyroidism as their primary disorder."

[helvella in reply to tattybogle]

I actually agree with this phrase from Saeed Taheri

I think you have an incomprehensibly valuable opportunity

Clearly incomprehensible.

But, yes, hypothyroidism seems worse than hyperthyroidism. [ Corrected! ]

[tattybogle in reply to helvella]

i though it meant the other way round , hyper better than hypo ? but haven't read it properly just skimmed it as brain is being too scatty just now .

[helvella in reply to tattybogle]

You are right - I made a hash of typing and corrected to be the wrong way round!

I will edit now.

[tattybogle in reply to helvella]

Glad it's not just me being scatty brained then

[helvella in reply to tattybogle]

I think we all have the highest order of skills in that direction.

[tattybogle in reply to helvella]

i can multitask , i can be scatty brained and do three other things badly at the same time .

[DippyDame in reply to tattybogle]

I sometimes console/kid myself with this!!

Alice

[tattybogle in reply to DippyDame]

[shaws in reply to tattybogle]

[shaws in reply to tattybogle]

[shaws]

Thanks for posting helvella. I have had the experience of excessive heartbeats when on levo only