Risk of coronary heart disease and ischemic stroke in thyroid cancer patients taking levothyroxine.

105Background: Many thyroid cancer patients are exposed to long-term TSH suppression, in many cases as lifetime treatment, and are consequently subjected to risk for cardiovascular disease. We investigated incidence of CHD and ischemic stroke among thyroid cancer patients and explored possible pathophysiological mechanisms involved. Methods: A total of 182,419 subjects who received thyroidectomy for thyroid cancer during 2004-2012 were selected from the Korean National Health Insurance data, which covers approximately 97% of the entire Korean population. Propensity score matching was used to select non-cancer controls. Cox proportional hazards regression analysis was used to determine relative risk of coronary heart disease (CHD), and ischemic stroke. Mean follow-up was 4.32 years. Results: Thyroid cancer patients had elevated risk for CHD and ischemic stroke with HR 1.15 (95% CI 1.10-1.22), and 1.15 (1.09-1.22), respectively. This risk was marked in those who received total thyroidectomy and in those who...