Patterns of Thyroid-Stimulating Hormone Test After GLP-1 RAs Initiation in Patients on Levothyroxine: A Trial...

Area of Science:

• Endocrinology
• Pharmacology
• Geriatrics

Background:

• Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) promote significant weight loss in patients with type 2 diabetes and obesity.
• Weight loss can decrease levothyroxine requirements, necessitating thyroid-stimulating hormone (TSH) monitoring to prevent adverse effects.
• Current practices for reassessing thyroid function after initiating GLP-1 RAs are not well-defined.

Purpose of the Study:

• To investigate the timing of TSH testing following the initiation of GLP-1 RAs.
• To compare TSH testing patterns between GLP-1 RAs and sodium-glucose cotransporter-2 inhibitors (SGLT-2is).

Main Methods:

• Retrospective cohort study using Medicare claims data (2011-2020).
• Propensity score matching (1:1) was employed to create comparable groups.
• Included adults aged ≥65 years with type 2 diabetes on stable levothyroxine doses.

Main Results:

• 83.0% of patients in both GLP-1 RA and SGLT-2i groups received TSH testing within one year.
• The mean time to TSH testing was approximately 130.5 days for both treatment groups.
• No significant difference in TSH testing timing was observed between the groups.

Conclusions:

• TSH testing frequency and timing did not differ between GLP-1 RAs and SGLT-2is users.
• Despite potential levothyroxine dose adjustments due to weight loss from GLP-1 RAs, monitoring patterns remained similar.
• This highlights potential missed opportunities for weight-responsive thyroid monitoring in patients using GLP-1 RAs.