Endocrine Abstracts

Thyroid dysfunction is associated with increased risk of cardiovascular disease (CVD) in general population, but it remains controversial whether the treatment of differentiated thyroid cancer (DTC) including thyroidectomy and thyroid stimulating hormone suppression add any risk of CVD compared to general population. We performed a systematic review of observational studies reporting associations between DTC and CVD in MEDLINE, EMBASE, Web of Science and other source (PROSPERO: CRD42020223057). We excluded studies with CVD evaluated as a comorbidity prior to thyroid cancer diagnosis or those with active surveillance without thyroidectomy. Risk of bias was assessed by ROBANS version 2.0. Risk estimates were pooled using random-effects and fixed-effects models when ≥ 3 studies reported data for each outcome. Eighteen studies were included. Compared to general population, DTC was associated with higher risks of atrial fibrillation (pooled risk ratio (RR) 1.55 [95% confidential interval (CI) 1.41–1.71]), coronary artery disease (RR 1.09 [1.01–1.17]), and cerebrovascular accident (RR 1.14 [1.09–1.20]), but not heart failure (RR 0.96 [0.78–1.18]) nor all-cause mortality (RR 1.31 [0.81–2.11]). To elucidate the direct effect of treated DTC on cardiovascular disturbance, clinical, echocardiographic, and hemodynamic parameters were also analyzed. DTC was associated with the higher heart rate (standardized mean difference [SMD], 0.34; 95% CI, 0.15‒0.56; P = 0.002) and left ventricular mass index (SMD, 0.66; 95% CI, 0.43‒0.90; P < 0.00001) and lower E/A ratio (SMD, -0.42; 95% CI, -0.79‒0.05; P = 0.03), but not with ejection fraction nor blood pressure. In conclusion, results suggested possible association between DTC and the higher risk of CVD and atrial fibrillation as well as increased heart rate and left ventricular mass. A large prospective study with long term follow-up is required to confirm the association of two disease entities.