Hypothyroidism Prevalence in the United States: A Retrospective Study Combining NHANES and Claims Data, 2009–2019

[helvella]

This USA paper discusses prevalence of hypothyroidism in the USA. And comes up with 11.7% in 2019.

That same year, the NICE guidelines said "about 2%" for the UK.

An astonishing difference.

Is the USA figure ludicrously high? Or the UK figure improbably low? Or is there such a large real difference?

Hypothyroidism is found in about 2% of the UK population and in more than 5% of those over 60. Women are 5 to 10 times more likely to be affected than men.

nice.org.uk/guidance/ng145/...

Hypothyroidism Prevalence in the United States: A Retrospective Study Combining National Health and Nutrition Examination Survey and Claims Data, 2009–2019

Kathleen L Wyne, Lekshmi Nair, Chris P Schneiderman, Brett Pinsky, Oscar Antunez Flores, Dianlin Guo, Bruce Barger, Alexander H Tessnow

Journal of the Endocrine Society, Volume 7, Issue 1, January 2023, bvac172, doi.org/10.1210/jendso/bvac172

Abstract

Previous estimates determined prevalence of hypothyroidism (HT) to be 4.6% of the US population. This study aimed to update estimates of HT prevalence in the United States by retrospective analysis of 2 datasets. Data on HT type (overt or subclinical HT) and treatment were collected from the 2009-2010 and 2011-2012 National Health and Nutrition Examination Survey (NHANES) cycles. From the Optum administrative claims database, medical and pharmacy claims were collected between January 1, 2012, and December 31, 2019. Patients were defined as having HT if, per given year, they had >1 prescription for HT treatment, >1 claim indicating an HT diagnosis, or thyroid-stimulating hormone levels >4.0 mIU/L (NHANES arm). For both studies, treatment was defined as any evidence of synthetic or natural thyroid hormone replacement, identified by pharmacy claims or patient surveys. Data are reported as percentage of patients with HT and treatments received. Between 2009 and 2012, HT prevalence remained around 9.6% of the US population. The administrative claims dataset showed that HT prevalence grew from 9.5% in 2012 to 11.7% in 2019 and that >78% of patients received thyroxine (T4) monotherapy. Similarly, the NHANES dataset showed that T4 replacement therapy was the most common treatment for HT. From 2012–2019, patients with untreated HT grew from 11.8% to 14.4%. The prevalence of HT in the United States has steadily increased since 2009. Likewise, the percentage of hypothyroid-diagnosed patients not receiving treatment also increased, suggesting that the increased prevalence may be due to increased cases of subclinical HT.

hypothyroidism, epidemiology, retrospective study, administrative claims database

Open access of full paper:

academic.oup.com/jes/articl...

[Zazbag]

I think the UK figure is improbably low. I had tested positive for TPO antibodies and had borderline high TSH for 5 years before they bothered to diagnose me. I was told I was just stressed. I wonder how many other patients have been gaslighted in the same way and told there's nothing wrong with them?

[helvella Administrator Thyroid UK in reply to Zazbag]

I certainly agree the UK figure is unlikely. Especially with the refusal of many doctors to recognise any issues with TSH out of reference interval and (sometimes) even when over that magic and arbitrary level of 10.

[jimh111]

Will study it when I have time. My initial impression is that they are over-diagnosing given the small proportion of patients in the so call 'subclinical hypothyrodism' group. Probably driven by money in private practice.

This is a sad state of affairs as on the one hand we have the UK under-diagnosing and the USA over-diagnosing, driven no doubt by a blind allegance to numbers. A knock on effect is that many retrospective studies will have limited value as the patient cohorts will not truly represent hypothyroidism (insufficient thyroid hormone activity).

[Batty1]

I bet the US number is even higher the doctors don’t even look into possible thyroid problems when you come in with typical thyroid symptoms its always something else …. This is exactly what happened to me over the years.

[arTistapple]

Weeell. I am pretty sure I have gone undiagnosed for a minimum of twenty years and likely more. So if that is common and frankly no reason to think otherwise seeing the stories on here, that would mess up the statistics somewhat. Recently saw a post here saying undiagnosed people lasted 12 years. Maybe it was ‘untreated’? Not sure how this would fit my experience other than a very slow development. Although it did not feel like it to me!

[helvella Administrator Thyroid UK in reply to arTistapple]

Twelve years was, pre-1900-ish, regarded as a time from something being wrong to death. But they didn't properly understand that it was the lack of thyroid hormone that was the issue.

Clearly, this time could vary hugely.