Effect of Thyroid-Stimulating Hormone Suppression Therapy on Cardiac Structure and Function in Patients With Differentiated Thyroid Cancer After Thyroidectomy: A Systematic Review and Meta-Analysis

Objective: We aimed to evaluate the effects of thyroid-stimulating hormone (TSH) suppression therapy on cardiac structure and function in patients with differentiated thyroid cancer (DTC) following thyroidectomy.

Methods: Two investigators independently searched the PubMed, Embase, Cochrane Library, and Web of Science databases for relevant studies published from inception to January 6, 2023, without any restrictions on language. Standard mean differences and 95% confidence intervals were calculated using fixed or random effects models. Thirteen clinical outcomes were analyzed, mainly evaluating cardiac morphology, systolic function, and diastolic function.

Results: Thirteen studies were included in the quantitative analysis. Compared to healthy controls, left ventricular mass index, left ventricular posterior wall thickness, interventricular septal thickness, and isovolumic relaxation time values increased; the ratio of E-wave velocity to A-wave velocity and E-wave velocity values decreased. The left ventricular ejection fraction and cardiac output did not change in patients with DTC who underwent long-term TSH suppression therapy. Interventricular septal thickness values were significantly correlated with the duration of TSH suppression therapy.

Conclusion: Long-term TSH suppression therapy leads to cardiac hypertrophy and impaired cardiac diastolic function in patients with DTC. These changes may be related to the duration of TSH suppression therapy. Large prospective studies with long follow-up periods are needed to validate these findings.