Systemic Thyroid Hormone Status During Levothyroxine Therapy In Hypothyroidism: A Systematic Review and Meta-Analysis

[helvella]

The paper says: Whether this approach universally restores thyroid hormone signaling is unknown. I beg to differ. It is has often been reported that simply normalizing TSH does NOT fix everything! Heigh-ho. At least it is another chunk of information.

Full paper behind paywall.

J Clin Endocrinol Metab. 2018 Aug 15. doi: 10.1210/jc.2018-01361. [Epub ahead of print]

Systemic Thyroid Hormone Status During Levothyroxine Therapy In Hypothyroidism: A Systematic Review and Meta-Analysis.

McAninch EA1, Rajan KB2, Miller CH3, Bianco AC4.

Author information

1 Division of Endocrinology and Metabolism, Rush University Medical Center, Chicago, IL, USA.

2 Division of Biostatistics, University of California Davis School of Medicine, Davis, CA, USA.

3 Galter Health Sciences Library, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.

4 Section of Endocrinology, Diabetes and Metabolism, University of Chicago, Chicago, IL, USA.

Abstract

Context:

The standard of care for overt hypothyroidism is levothyroxine at doses that normalize serum TSH levels. Whether this approach universally restores thyroid hormone signaling is unknown.

Objective:

To review studies of overt hypothyroidism in which participants were treated with levothyroxine to normalize serum TSH levels and measured other objective markers of thyroid hormone signaling.

Design:

Databases were searched for studies that reported objective markers of thyroid hormone signaling (serum low-density lipoprotein (LDL), total cholesterol (TC), sex hormone-binding globulin (SHBG), creatine kinase and/or ferritin levels; cognition, energy expenditure, and/or renal function) in levothyroxine monotherapy for overt, primary hypothyroidism among nonpregnant adults with normal serum TSH levels. For studies with LDL, TC and SHBG outcomes, data were pooled using random effects meta-analysis.

Results:

A total of 99 studies met inclusion criteria, including 65 that reported serum cholesterol data. Meta-analysis showed that levothyroxine-treated hypothyroid participants with normal serum TSH levels had 3.31 ± 1.64 mg/dL higher serum LDL levels (p=0.044) and 9.60 ± 3.55 mg/dL higher serum TC levels (p=0.007) compared to controls. In studies that did not concomitantly assess healthy controls, serum LDL levels were 138.3 ± 4.6 mg/dL (p<0.001) and serum TC levels were 209.6 ± 3.4 mg/dL (p<0.001). Meta-analysis of 2 studies showed no significant difference between SHBG levels of levothyroxine-treated participants and controls.

Conclusions:

In studies that utilized levothyroxine monotherapy at doses that normalized the serum TSH for overt, primary hypothyroidism, not all systemic biological markers of thyroid hormone signaling were normalized, including serum LDL and TC levels.

PMID: 30124904

DOI: 10.1210/jc.2018-01361

ncbi.nlm.nih.gov/pubmed/301...

[Added 22/08/2018 22:07 ]

Link to diogenes' post about this paper:

healthunlocked.com/thyroidu....

[diogenes Remembering]

You know, this kind of paper makes me wonder as to whether the "gurus" in thyroidology like Bianco and his coworkers have the overt strategy of deliberately ignoring our work or are either a) ignorant of it (unlikely), b) know it but don't understand it, or c) understand it but don't want to acknowledge that their academic feet have been swept from under them and therefore ignore it (most likely). They plough through the same old story from the conventional diagnostic angle, to discover if the conventional angle is indeed right. And naturally come up with ambiguity and "perhaps and perhaps not'. I think that the powerful medical hierarchy will do anything to either protect their position, or if it is challenged, ignore the challenge until they can come up with their own (respectable of course being from the "right" direction) version and claim their no doubt self-appointed and deserved kudos for "first" finding it out. orry to be sour but this seems to be the order of the day.

[helvella in reply to diogenes]

Am very glad to see your comment.

I rather expected you to come along. And it really does look odd.

Perhaps they have a room full of papers they have not yet published going back many years and can't change anything until they have used them all up?

[diogenes Remembering in reply to helvella]

I've obtained a full copy of this paper and sent to Louise Roberts for archiving. Again shows that normal service (i.e. cholesterol levels) is not resumed when T4 therapy gives normal range TSH levels. Just like SHBG and several other indirect thyroid function markers. Thus as we've said, the TSH range typical of health doesn't apply in therapy.

[Tile]

A suppressed TSH is the way to go. My lipids are optimal and can eat all the cholesterol loaden dairy and meats out there. Trigs are 80 and I'm no athlete.

[Tile in reply to Tile]

Ps I NEVER FAST for lipid tests..This is on T4 only.

[Parbrook]

So, biological markers continue to take precedence over symptoms?