Cardiovascular Outcomes of Differentiated Thyroid Cancer Patients on Long Term TSH Suppression: A Systematic Review and Meta-Analysis.

We performed a systematic review and meta-analysis of the literature regarding cardiovascular outcomes of differentiated thyroid cancer (DTC) patients who are on long term thyroid stimulating hormone suppression. Searches were carried out using Prisma guidelines in Medline, Embase, CENTRAL, CINAHL and Scopus databases. Eligible papers were those which investigated discrete cardiovascular clinical outcomes in TSH suppressed patients and meta-analysis of selected studies was performed using Revman 5.4.1. We found a total of 195 879 DTC patients with median length to follow up of 8.6 years (range 5-18.8 years). Analysis showed DTC patients to be at higher risk of atrial fibrillation (HR 1.58, 95% CI 1.40, 1.77), stroke (HR 1.14, 95% CI 1.09, 1.20) and all-cause mortality (HR 2.04, 95% CI 1.02, 4.07). However, there was no difference in risk of heart failure, ischemic heart disease or cardiovascular mortality. These findings suggest that degree of TSH suppression must be titrated to accommodate risk of cancer recurrence and cardiovascular morbidity.