Muddled logic in a 2016 Choosing Wisely article against T3 testing

Here’s a brief article from October 2016 — yes two years ago — from our nemesis the Choosing Wisely campaign, their American branch.

From the Cleveland Clinic.

• LeGros, K. (2016, October 3). Choosing Wisely®: Thyroid Function Testing. Retrieved November 4, 2018, from https://clevelandcliniclabs.com/2016/10/03/recommendations-from-the-choosing-wisely-initiative-thyroid-function-testing/

I’d just like to point out some muddled logic in this quote below and the way they try to support it, and fail:

“Don’t order a total or free T3 level when assessing levothyroxine (T4) dose in hypothyroid patients, as treatment itself may impact T3 levels.”

Yes, in fact, treatment with T4 alone can adversely “impact” T3 levels, lowering them in a harmful way.

So why should we not measure T3 in these patients to see if they are being harmed by levothyroxine therapy?

This article effectually says that the therapy may impact T3 levels — but you should not measure the impact it has. What?

This quoted sentence has a citation on it.

It leads you to a 2015 article, “Screening for Thyroid Dysfunction: U.S. Preventive Services Task Force Recommendation Statement”.

• I went to the full text version of this article.
• I searched for “T3.”
• T3 was only mentioned in the context of HYPERthyroidism.

Reading further in this article, one can find NO directives regarding NOT testing T3, much less not testing it in patients on thyroid therapy.

Most of the article’s conclusions were limited to the “screening” of undiagnosed patients who did NOT have any symptoms of hypo or hyperthyroidism.

In other words, citing this article does not support anything in Choosing Wisely’s recommendation against T3 testing _within_ hypothyroid therapy.

The article even offered a sentence that went _against_ the Choosing Wisely recommendation when it acknowledged the errors that can arise from lack of thorough testing and the reliance on one single test alone — the TSH:

“The high variability of TSH secretion levels and the frequency of reversion to normal thyroid function without treatment underscore the importance of not relying on a single abnormal laboratory value as a basis for diagnosis or the decision to start therapy.”

So back to the Cleveland Clinic’s “Choosing Wisely” thyroid article.

1. They make recommendations that are intrinsically illogical given what science teaches about the importance of the T3 hormone, and
2. They use a citation to an article that does not explain or support their claim, likely hoping that merely citing something will make them appear authoritative.

All doctors and endocrinologists who don’t check the source of citations and the logical reasoning based on them are swallowing these unsubstantiated and illogical claims based on false authority.

Many likely believe because these claims happen to fall in line with the current dogma of TSH testing and the defense of T4 monotherapy.