Large Study on under- or over treatment on T4

[diogenes]

This study is interesting, because among other things, it shows that if TSH has been low for some time, even after 10 years "correction, it does not rise for about half the subjects. And T4 therapy was started in quite a large minority of patients with TSH < 5 mIU/L. I don't like the definitions of under and over treatment as regards TSH values for most, but the risks seem very small. Behind a paywall

Risk of over-and under-treatment with levothyroxine in primary care in Copenhagen, Denmark

J L la Cour, BR Medici, Mia Klinten Grand ,DR Nicolaisdottir, B Lind et al

European Journal of Endocrinology 185:673-679: 2021

Doi: doi.org/10.1530/EJE-21-0485

Objective

A decrease over time in thyroid stimulating hormone (TSH) levels when initiating levothyroxine (L-T4) therapy for hypothyroidism has been reported, where treatment most often is initiated with TSH levels below 10 mIU/L. The primary objective of this study was to investigate whether this lower TSH threshold resulted in an increased number of overtreated patients.

Design and method

Retrospective cohort study comprising inhabitants in Copenhagen had TSH measurements requested by general practitioners which led to a new prescription of L-T4 between 2001 and 2012. Over- and under- treatment were defined as TSH <0.1 mIU/L or above 10 mIU/mL, respectively, in three consecutive measurements. Data were analyzed by Aalen–Johansen estimators and Cox proportional hazards models.

Results

In total, 14 533 initiations of L-T4 were included in the study. The cumulative risk of being over- or undertreated was 4.7 and 7.4% after 10 years. The hazard of overtreatment was higher among women, younger adults, and with lower initial TSH levels. The hazard of overtreatment decreased over the time period from 2001 to 2012. Among overtreated individuals, the chance of returning to a normal TSH was about 55% after 10 years. In 18% of the cases, L-T4 therapy was initiated on TSH levels less than 5 mIU/L.

Conclusion

Although a still decreasing threshold for initiating L-T4 therapy is known, the risk of overtreatment (and undertreatment) was low and lessened in the period 2001–2012 among Danish primary

[jimh111]

Just to note there is a similar study in Germany, also released today doi.org/10.1530/EJE-21-0916 . Free access but I won't have time to look at it.

[Musicmonkey]

Thank you for sharing this diogenes

[Hidden]

As far as I understand this study, it only uses the TSH to determine if a person is under- or overtreated. In other words, they don´t care about the free Ts. A person can have a TSH of <0.1, low free T3 and display hypo symptoms, yet be diagnosed as overtreated by doctors and have levo lowered until the TSH normalises.

[jgelliss in reply to Hidden]

Ditto!!! Thank you for bringing attention to this very big problem. I was a recipient of just this treatment/care for years after my TT. My FT-3 was in the tank my FT-4 was over range and my TSH was close to 0. I experienced all sorts of awful side effects. Yet the Dr's all thought I was doing great . Great lesson to please trust yourself and to advocate for yourself.

I feel Blessed having found this Great Forum.

[TSH110 in reply to jgelliss]

So much for listening to the patient 🙄

[jgelliss in reply to TSH110]

You are Spot On TSH110 . Never mind that they don't listen to patients. But patients rely on these same Dr's who know next to nothing when it comes to dosing patients with thyroid meds. This is what we are up against.

What are we supposed to do to feel our very best . Our G-D given Rights.

[T808]

Exactly, my doctor won't even test ft3 but my TSH just came back TSH w/FT4 Reflex 1.03 0.270-4.20 on 112.5mcgs of levo for 6 weeks. But I feel hypo. He actually had me on 100mcgs but I felt even more hypo so I changed my dose to 112.5 by splitting extra 100mcg pills into 1/8s and just didn't plan on telling him until my labs came back. But I did feel better with that slight dose increase. I still have hypo symptoms even on 112.5.

[TSH110 in reply to T808]

This study and the German one based on it seems devoid of considering how the actual people feel symptoms appear to be irrelevant to them. They pick the TSH numbers and that’s it - job done. If that huge range is how they determine over and under treatment it’s a very blunt tool indeed. I don’t really get what they are driving at. Is it that treating at TSH of 5 is better than 10? Bit patently obvious if people with properly functioning thyroid have a TSH not much over 1.5…but not if you’re an endocrinologist and brain dead!

[T808 in reply to TSH110]

Well, I tried 125mcgs for a 3 or 4 days and yesterday and today my heart is racing when doing trivial things. Tinnitus came back, and only slept 4 hours last night instead of 6 or 7. Heart rate variation went down to 23. And my heart rate while sleeping stayed above my resting heart rate when normally it dips 10 or 15 beats lower during sleep. Kept feeling hypoglycemia the last couple days too. It's amazing that I stayed on 150mcgs for 20+ years and felt super healthy until recently. And now I can't even take 125 without issues. Only thing that changed was I went gluten free 3 or 4 years ago and had covid in August. And this started probably 3 or 4 months after having covid. Wonder if it just changed me

[TSH110 in reply to T808]

It is strange. Do you think your thyroid is still doing something? I read bits of it can start functioning again after many years after a thyroidectomy but it can’t fully regenerate like say a liver can. It has happened to at least one person on the forum and it was about 20 years after a TT. Covid does interfere with the thyroid hormones too maybe that has upset your equilibrium it seems a bit of a coincidence especially give all the latest findings about it shrinking brains, lord knows what else it might do to a person long term. I do hope you manage to get back on track soon 🍀☘️🍀

[T808 in reply to TSH110]

I thought it might have started working again since I needed such a drastic dosage change after being on it so long. Had a full thyroid panel done a year ago and everything was good. But recently they did a thyroid ultrasound, don't know if they can see if it's working or not from that but I haven't heard anything about that since going in. It's been a month now I think since the ultrasound. Thank you. You guys definitely help brain storm and figure things out. Doctors are really terrible at that. Most anyways. Hope you're doing well yourself 🙏

[TSH110 in reply to T808]

I think they can only see the structure not the function. I was told mine was very small and shrivelled and unlikely to have any function so it was a deduction on his part based on its appearance. Perhaps if it is working it might show in an ultrasound but I am not convinced it would. I presume they could see function on an MRI if they gave you something that shows up on the scan and is tagged to something containing iodine so it is taken up readily by any functioning thyroid tissue. I think it used to be a nuclear medicine scan but I imagine MRI has superceded it.

[T808 in reply to TSH110]

I have a new doctor now, because I couldn't stand the other one. He made me worse. That's how I lost 16kilos in a month. When I originally went to him with my hyper symptoms from 150mcgs he told me I was hypo and put me on 175mcgs for 6 weeks but I only got 3 weeks in before I was bed ridden and my hair was falling out in clumps. So ill talk to this new doctor about checking to see if I have any thyroid function left just to be sure it somehow didn't wake up. My Mom's friend had that also happen after 10 years of it being "dead" just to be sure. 100mcgs or 112 seems like a really low dose to be on post RAI.

[TSH110 in reply to T808]

Scary stuff!

[tattybogle]

" The cumulative risk of being over- or undertreated was 4.7 and 7.4% after 10 years".

Wonder if the authors express any concern about the rather larger chance of having TSH over 10, 3 times in a row , whilst being 'treated' on Levo ? I really hope most of these '3 over 10' results were from people just starting treatment with very high initial TSH , and not from people who were on a settled dose.

" Among overtreated individuals, the chance of returning to a normal TSH was about 55% after 10 years." ( .... we have no idea if they felt better or worse for it ....because nobody bothers to record annoying complicated details like that.. but hurray their TSH is in range !)