Related Experiment Video
Updated: Mar 29, 2026
Generation of a Mouse Spontaneous Autoimmune Thyroiditis Model
Published on: March 17, 2023
Patterns of TSH test after GLP-1 RAs initiation in patients on levothyroxine: a trial emulation study
Yishan Chen1, Fanxing Du1, Naykky M Singh Ospina2
1Department of Pharmaceutical Outcomes and Policy, College of Pharmacy, University of Florida, Gainesville, FL 32611, USA.
Context:
Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are widely prescribed for type 2 diabetes and obesity and can lead to substantial weight loss. In patients taking levothyroxine, weight loss can reduce thyroid hormone requirements and potentially associated adverse effects. Thyroid-stimulating hormone (TSH) monitoring is essential but unclear whether thyroid function is routinely reassessed after GLP-1 RAs initiation.
Objective:
Examine the changes in the timing of TSH testing after GLP-1 RAs.
Design:
Retrospective cohort study emulating a target trial using Medicare from January 1, 2011, to December 31, 2020. The primary analysis followed an intention-to-treat approach. Patients were matched 1:1 using propensity scores. Logistic regression models and informed by least absolute shrinkage operator variable selection were used.
Setting:
The 15% sample of U.S. Medicare fee-for-service claims data.
Patients Or Other Participants:
Adults aged ≥65 years with type 2 diabetes on a stable levothyroxine dose at baseline.
Intervention(S):
Initiation of GLP-1 RAs vs initiation/ongoing use of sodium-glucose cotransporter-2 inhibitors (SGLT-2is).
Main Outcome Measure(S):
TSH testing during follow-up.
Results:
Among 5370 matched patients, the mean age was 73.2 years. 71.6% were women, and 87.1% were White. Approximately 83.0% of patients in both treatment groups receive a TSH testing within a 1-year follow-up. The mean time to TSH testing was approximately 130.5 days for both groups.
Conclusion:
TSH testing patterns did not differ between GLP-1 RAs and SGLT-2is, despite the greater likelihood of requiring levothyroxine dose adjustment associated with weight loss seen with GLP-1 RA therapy. Given levothyroxine's widespread use, this gap suggests missed opportunities for timely and weight-responsive thyroid monitoring.
Related Concept Videos
01:20Synthesis and Regulation of Thyroid Hormones
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The...
01:24Glucagon-like Receptor Agonists
GLP-1, when administered in high doses intravenously, triggers insulin secretion, inhibits glucagon release, slows gastric emptying, reduces food intake, and restores normal insulin secretion. However, its rapid inactivation by...
01:18Functions of Thyroid Hormones
TH is indispensable for the normal development and maturation of the skeletal, muscular, and nervous systems during fetal and childhood growth. It facilitates bone mineral turnover and regulates protein synthesis in developing tissues, contributing significantly to overall growth and...
01:23The Thyroid Gland
The follicles have a central cavity lined by simple cuboidal to squamous epithelial cells called follicular cells. These cells produce the glycoprotein...
01:19Regulation of Hormone Secretion
Humoral...
01:22Target Cell Response to Hormones
Notably, the cellular response can be regulated by altering the number of receptors expressed in the cell. For example, prolonged exposure to elevated hormone levels results in a gradual decline or down-regulation in the number of receptors for that specific hormone on the cell surface. Conversely, in response to low hormone levels, cells may use up-regulation, producing an...