A team from the University of Alabama at Birmingham School of Public health collaborated with other researchers to evaluate the association between cancer and cerebrovascular disease in a prospective cohort study with adjudicated cerebrovascular diagnoses. Drs. Virginia Howard, Hong Zhao, and Paul Muntner from the department of epidemiology and Drs. George Howard and Suzanne Judd from the department of biostatistics comprised the UAB group.
[Photo: Dr. Virginia Howard]
[Photo: Dr. George Howard]
The team analyzed participants from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study who were 45 years and older and had Medicare coverage for 365 days before their baseline study visit. Participants with a history of cancer or cerebrovascular events were excluded from the study. The time-dependent exposure was a new diagnosis of malignant cancer identified through Medicare claims algorithms. Participants were prospectively followed from their baseline study visit (2003–2007) through 2014 for the outcome of a neurologist-adjudicated cerebrovascular event defined as a composite of stroke (ischemic or hemorrhagic) or transient ischemic attack (TIA). Cox regression was used to evaluate the association between a new cancer diagnosis and subsequent cerebrovascular events. Follow-up time was modeled in discrete time periods to fulfill the proportional hazard assumption.
They found that among 6,602 REGARDS participants who met eligibility criteria, 1,149 were diagnosed with cancer during follow-up. Compared to no cancer, a new cancer diagnosis was associated with subsequent cerebrovascular events in the first 30 days after diagnosis (hazard ratio 6.1, 95 percent confidence interval 2.7-13.7). This association persisted after adjustment for demographics, region of residence, and vascular risk factors (hazard ratio 6.6, 95 percent confidence interval 2.7-16.0). There was no association between cancer diagnosis and incident cerebrovascular events beyond 30 days. Cancers considered high risk for venous thromboembolism demonstrated the strongest associations with cerebrovascular event risk.
The researchers concluded that a new diagnosis of cancer is associated with a substantially increased short-term risk of cerebrovascular event.