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Cosmos Study

Patients Who Lose Weight After Starting GLP-1s More Likely to See Thyroid Level Improvement

November 19, 2024
Dual-Team Study
Team A:Dave Little, MDJoe Deckert, PhD
Team B:Kersten Bartelt, RNJoe Longo

Key Findings

  • Patients with hypothyroidism who lose more than five pounds after starting a GLP-1 medication experience on average a 0.36 mU/L to 0.55 mU/L reduction of their thyroid-stimulating hormone (TSH) levels. 

Previous research has shown conflicting results regarding correlation between GLP-1 medications and thyroid function.1 Some have theorized that GLP-1 medications may affect metabolic pathways, potentially altering thyroid hormone production.1 Weight loss has also been correlated with changes in thyroid levels.2  

We aimed to understand the relationship between GLP-1 medications, weight change, and thyroid-stimulating hormone (TSH) levels. Lower TSH levels indicate improved thyroid function. We studied 21,538 patients with a history of hypothyroidism who were prescribed semaglutide, dulaglutide, liraglutide, or exenatide and stratified them by their weight change after starting the medication. The amount of weight change was calculated using the patient’s weight when they started the GLP-1 medication and their weight when a follow-up TSH level was taken. We found that patients who were prescribed semaglutide and lost more than five pounds saw the greatest reduction of their TSH levels, as seen in Figure 1. Patients who gained weight while prescribed any of the GLP-1 medications studied had no statistically significant change in their TSH levels. 

Figure 1
Change in TSH Levels After Starting GLP-1 Medication by Weight Change
Change in TSH Levels After Starting GLP-1 Medication by Weight Change
Figure 1. Change in TSH levels after starting a GLP-1 medication by weight change.

These data come from Cosmos, a dataset created in collaboration with a community of Epic health systems representing more than 277 million patient records from 1,500 hospitals and more than 36,000 clinics from all 50 US states, Lebanon, and Saudi Arabia. This study was completed by two teams that worked independently, each composed of a clinician and research scientists. The two teams came to similar conclusions. Graphics by Brian Olson. 

References

  1. Capuccio S, Scilletta S, La Rocca F, Miano N, Di Marco M, Bosco G, Di Giacomo Barbagallo F, Scicali R, Piro S, Di Pino A. Implications of GLP-1 Receptor Agonist on Thyroid Function: A Literature Review of Its Effects on Thyroid Volume, Risk of Cancer, Functionality and TSH Levels. Biomolecules. 2024; 14(6):687. https://doi.org/10.3390/biom14060687 
  2. Agnihothri RV, Courville AB, Linderman JD, et al. Moderate weight loss is sufficient to affect thyroid hormone homeostasis and inhibit its peripheral conversion. Thyroid. 2014;24(1):19-26. doi:10.1089/thy.2013.0055