PB0030 - A Population Cohort Study to Evaluate the Risk of Ischemic Stroke Among Individuals with a New Diagnosis of Cancer Compared to Matched Cancer-Free Controls: Impact of Prior Stroke History

Sunday, July 10, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Presenting Author(s)

Deborah M. Siegal, MD MSc FRCPC

Tier 2 Canada Research Chair in Anticoagulant Treatment of Cardiovascular Disease Hematologist
The Ottawa Hospital
Ottawa, Ontario, Canada

Co-Author(s)

JC

Joshua Cerasuolo

Analyst
ICES
Hamilton, Ontario, Canada
Marc Carrier, MD

MD, MSc
Ottawa Hospital Research Institute, Ottawa, ON, Canada
Ottawa, Ontario, Canada
PG

Peter Gross

Associate Professor
Department of Medicine, McMaster University
Hamilton, Ontario, Canada
MK

Moira Kapral, MD MSc FRCPC

Professor/Scientist
University of Toronto/ICES
Toronto, Ontario, Canada
RL

Ronda Lun, MD

Neurology Resident/MSc Candidate
University of Ottawa
Ottawa, Ontario, Canada
MS

Michel Shamy, MD MSc FRCPC

Associate Professor
University of Ottawa
Ottawa, Ontario, Canada
RS

Rinku Sutradhar, PhD

Associate Professor/Senior Scientist
University of Toronto/ICES
Toronto, Ontario, Canada

Background: The association between cancer and ischemic stroke is not well understood.

Aims: To measure the risk of ischemic stroke in individuals with newly diagnosed cancer compared to cancer-free controls in two matched cohorts based on prior history of ischemic stroke.

Methods: Using linked health databases in Ontario, Canada (2010 to 2019), we conducted a population-based cohort study of adults with newly diagnosed cancer matched to controls (1:1) by age and sex. The primary outcome was the incidence of ischemic stroke. Subdistribution adjusted hazard ratios (aHR) were calculated. aHRs were estimated before and after 1.5-years to account for interactions between time and exposure.

Results: Among 1,241,294 individuals without prior stroke, the rate of ischemic stroke was 4.6/1000 person-years (95%CI 4.5-4.7) in cancer patients and 3.5/1000 person-years (95%CI 3.4-3.6) in controls (p < 0.0001). At 1.5 years, the risk of ischemic stroke was higher in cancer patients (CIF estimate 0.71% vs. 0.49%; aHR 1.40, 95%CI 1.34-1.47) (Table 1). At 5 years, the risk of ischemic stroke was lower in cancer patients (CIF estimate 1.60% vs. 1.68%; aHR 0.72, 95%CI 0.69-0.74).

Among 27,848 individuals with prior stroke, the rate of ischemic stroke was 26.9/1000 person-years (95%CI 25.1-28.9) in cancer patients and 22.0/1000 person-years (95%CI 20.7-23.4) in controls (p < 0.0001). The risk of ischemic stroke was similar at 1.5 years (CIF estimate 3.42% vs. 3.43; aHR 1.00, 95%CI 0.88-1.14). At 5 years, the risk of ischemic stroke was lower in cancer patients (6.13% vs. 8.40%; aHR 0.53, 95%CI 0.46-0.62).

Figure 1 shows cumulative incidence function (CIF) curves for the overall cohort and cancer subtypes.

Conclusion(s): In individuals without prior stroke, those with newly diagnosed cancer had a 1.4-fold higher risk of ischemic stroke at 1.5 years versus controls but the risk varied by cancer type. Future analyses will evaluate stroke risk factors, treatments, and outcomes.