Arterial thromboembolic events preceding the diagnosis of cancer in older persons.

Cancer patients face an increased risk of arterial thromboembolism; however, it's uncertain when this excess risk begins. This study evaluated the risk of arterial thromboembolism before cancer diagnosis. Using the population-based Surveillance Epidemiology and End Results-Medicare linked dataset, we identified 374,331 patients ≥67 years of age with a new primary diagnosis of breast, lung, prostate, colorectal, bladder, uterine, pancreatic, gastric cancer, or non-Hodgkin lymphoma from 2005-2013. Cancer patients were individually matched by demographics and comorbidities to Medicare beneficiaries without cancer, who served as controls. Validated diagnosis codes were used to identify arterial thromboembolic events, defined as a composite of myocardial infarction or ischemic stroke. The Mantel-Haenszel estimator was used to compare risks of arterial thromboembolic events between cancer and non-cancer groups during 30-day periods in the 360 days before date of cancer diagnosis. From 360 to 151 days before cancer diagnosis, the 30-day interval risks of arterial thromboembolic events were similar between cancer patients and matched controls. From 150 to 1 day before cancer diagnosis, the interval 30-day risks of arterial thromboembolic events were higher in cancer patients versus matched controls, progressively increasing as the cancer diagnosis date approached, and peaking during the 30-days immediately before cancer diagnosis, when 2,313 (0.62%) cancer patients were diagnosed with an arterial thromboembolic event versus 413 (0.11%) controls (odds ratio, 5.63; 95% confidence interval, 5.07-6.25). In conclusion, the risk of arterial thromboembolic events begins to increase 150 days before the date of cancer diagnosis in older persons and peaks in the 30 days before.