Research

Hormonal

Initiation of GLP-1 receptor agonists (GLP-1RA) in older adults with type 2 diabetes on stable levothyroxine therapy significantly increases the risk of new-onset atrial fibrillation or flutter (AF/Aflutter) compared to SGLT2 inhibitors.

If you take levothyroxine and start a GLP-1RA (like Ozempic or Wegovy), your thyroid hormone levels may become too high because you lose weight or absorb the medication differently. This increases your risk of irregular heartbeats (AF). You need closer monitoring of your TSH levels and likely a reduction in your levothyroxine dose shortly after starting the GLP-1RA to prevent this.

GoodSupportsHIGH confidence
Compared to SGLT2 inhibitors, initiation of GLP-1RA was associated with higher risk of AF/Aflutter (HR: 1.46; 95% CI: 1.28–1.67)
Fanxing Du et al. · Cardiovascular Diabetology · 2025

Why this rating

Large-scale target trial emulation with propensity score matching and multiple sensitivity analyses, though observational data limits causal certainty compared to RCTs.

Source

Glucagon-like peptide-1 receptor agonists and risk for cardiovascular events in older adults treated with levothyroxine: a target trial emulation

Fanxing Du et al. · Cardiovascular Diabetology · 2025

DOI 10.1186/s12933-025-02971-7

cohort · n=4768Cited 3×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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