The dual GLP-1/GIP agonist tirzepatide is a highly effective anti-obesity therapy. While promising, it is associated with potential adverse effects, including thyroid disease reported in animal models. Due to limited human data, this study seeks to identify and characterise risk factors for thyroid disease development in patients undergoing 1 year of tirzepatide treatment. This study retrospectively analysed medical records of patients completing a 12-month course of tirzepatide (2.5-15 mg weekly) between September 2023 and September 2024. The primary endpoint is the development or worsening of any thyroid disease including DIT, Hashimoto thyroiditis, Graves' disease, benign neoplasms, goitre, and thyroid cancer. In 527 patients on tirzepatide, 28 (5.3%) developed or had progression of thyroid disease. The most frequent diagnoses were Nodular/Goitre Disease and Drug-Induced Thyroiditis. Multivariate analysis showed that a history of End-Stage Renal Disease (OR = 2.94) and baseline thyroid disease (OR = 3.78) were significant risk factors. Baseline thyroid disease and end-stage renal disease are significantly associated with an increased risk of new or recurrent thyroid disorders during tirzepatide treatment. These conditions should be classified as high risk, warranting periodic thyroid testing and further large-scale prospective validation.
Laos et al. (2026) studied this question.