Abstract WMP53: New Diagnosis of Cancer and the Risk of Subsequent Arterial Thromboembolic Events

Abstract

Background: Retrospective studies have reported an association between cancer and arterial thromboembolism risk. We sought to confirm this in a prospective cohort with adjudicated cardiovascular outcomes. Methods: We analyzed data from participants enrolled in the REasons for Geographic and Racial Differences in Stroke (REGARDS) study who had Medicare coverage for 365 days before their baseline study visit in 2003-2007. Participants with prevalent cancer, coronary heart disease, or cerebrovascular disease were excluded. Medicare claims were used to identify new cancer diagnoses during follow-up. Using incidence-density sampling, participants who developed cancer were matched by age, sex, race, and education level 1:4 to participants who hadn’t developed cancer. Participants were prospectively followed through September 30, 2015 for an adjudicated arterial thromboembolic event, defined as fatal or nonfatal acute myocardial infarction or ischemic stroke. Cox regression was performed to evaluate the association between incident cancer and subsequent arterial thromboembolic events. To fulfill the proportional hazard assumption, follow-up time was modeled in discrete time periods. Results: In this analysis, 836 REGARDS participants with incident cancer were matched to 3,339 participants without cancer. During median follow-up of 3 years, 63 (7.5%) participants with cancer and 216 (6.5%) participants without cancer had an arterial thromboembolic event. Compared to non-cancer controls, participants with incident cancer had an increased risk of arterial thromboembolic events in the first 30 days after diagnosis (HR, 5.2; 95% CI, 2.1-12.7). This association persisted after adjustment for demographics, region of residence, and cardiovascular risk factors (HR, 5.8; 95% CI, 2.1-15.9). Cancers with known metastases and types considered high-risk for venous thromboembolism had the strongest associations with arterial thromboembolic events. There was no association between cancer diagnosis and arterial thromboembolic event risk beyond 30 days. Conclusions: Incident cancer, particularly when metastatic, is associated with an increased short-term risk of arterial thromboembolic events independent of vascular risk factors.