Risk of thromboembolism according to statin treatment in patients with cancer: A nationwide nested case-control study

Background: Thromboembolic events exhibit increased prevalence in patients with cancer and can negatively affect prognoses. We investigated whether statin treatment would reduce thromboembolic risk in patients with cancer. Methods: We conducted a nested case-control study using a Korean nationwide health claims database. The study included patients newly diagnosed with cancer without a prior history of cardiovascular disease between 2014 and 2016. Cases who developed arterial thromboembolism (ATE) or venous thromboembolism (VTE) after cancer diagnosis and three individually matched controls were selected. Conditional logistic regression was used to assess the association between thromboembolic risk and statin therapy after cancer diagnosis. Results: Among 455,805 newly diagnosed patients with cancer followed for a mean of 4.3 ± 2.0 years, 22,249 patients developed thromboembolic events (ATE: 6341, VTE: 15,908), resulting in an incidence rate of 1133 per 100,000 person-years. The nested case-control study included 21,289 cases with thromboembolic events and 63,867 controls. Statin use was less frequent in the case group (18.0 % vs. 23.7 %). Statin treatment was associated with a lower risk of thromboembolic events (adjusted odds ratio [OR] 0.70; 95 % confidence interval [CI] 0.67–0.73). This association was observed for both ATE (adjusted OR 0.68; 95 % CI 0.63–0.74) and VTE (adjusted OR 0.71; 95 % CI 0.67–0.75). Longer statin use and better adherence were also associated with lower risk for thromboembolic events. Statin treatment was significantly associated with fewer thromboembolic events in most cancer types. Conclusions: Statin use was associated with lower risk for thromboembolic events in patients newly diagnosed with cancer.