Association Between Thyroid Cancer and Cardiovascular Disease Risk: A Nationwide Observation Study

Abstract BackgroundResearch findings on the long-term cardiovascular risk associated with thyroid cancer and treatment are unclear. This study aimed to investigate the standardized incidence rate (SIR) of coronary heart disease (CHD), ischemic stroke (IS), and atrial fibrillation (AF) among thyroid cancer patients in comparison with the general population across different age groups. MethodsDesign, setting, and participantsThis observational cohort study enrolled patients between January 1, 2011 and December 31, 2016 with follow-up until December 31, 2018. This study analyzed the data of Taiwanese thyroid cancer patients registered on the National Taiwan Cancer Registry Database, with CHD and IS. Main outcomes and measuresSIR models were used to evaluate the association between thyroid cancer and CHD, IS, AF, and cardiovascular disease outcome, stratified by age and sex. SIR analyses were also conducted for both sexes, age groups (<60, ≥60 years), and different follow-up years.ResultsAfter excluding 128 individuals <20 years or >85 years and with missing index data, 4274 eligible thyroid cancer patients without CHD history, 4343 patients without IS history, and 4247 patients without AF history were included for analysis. During the median follow-up of 3.5 (1.2) years, CHD incidence was 70; IS, 30; and AF, 20. Compared with the general population, thyroid cancer patients had higher CHD risk throughout the age spectrum (SIR, 1.33; 95% confidence interval [CI], 1.02 to 1.65). The overall CHD risk gradually declined, but it was persistent for more than 5 years after thyroid cancer diagnosis. CHD risk was observed in both males and females, especially in young thyroid cancer patients <65 years. However, lower SIRs for IS (SIR, 0.74; 95% CI, 0.47 to 1), AF (SIR, 0.74; 95% CI, 0.42 to 1.06), and cardiovascular disease (SIR, 0.88; 95% CI, 0.7 to 1.05) were observed among thyroid cancer patients (not significant). ConclusionsThyroid cancer survivors have a substantial CHD risk even at long-term follow-up, especially in those patients <65 years. Further research on the association between thyroid cancer and CHD risk is warranted.