Non-Hypertensives and Those with Normal Cholesterol Are More Likely to Have Concomitant Cancer amongst Patients with Ischemic Stroke: A Retrospective Cross-Sectional Registry-Based Study

Introduction: Patients with cancer are known to have an increased risk of ischemic stroke (IS) around the time of their diagnosis. However, there is a paucity of data in Asian populations, and as such, we aimed to determine cancer incidence rates and patterns in Asian IS patients as well as investigate the differences in vascular risk profile of IS patients with and without concomitant cancer. Methods: We conducted a retrospective cross-sectional study using data from the Singapore Stroke and Cancer registries. We defined cases as patients with IS and a cancer diagnosis 2 years before or after the index IS. Cancer incidence was determined using the same direct age-standardization method performed for the Singapore general population in the 2015 Singapore cancer report. Multivariable logistic regression was used to analyze differences in vascular risk factors. Results: Among 21,068 IS patients (mean age, 67.9 +/- 13.3 years), 6.3% (1,330) were found to have concomitant cancer; 4.4% (935) had prior cancer while 1.8% (395) had cancer diagnoses within 2 years following IS. The cancer incidence among IS patients was 3,393 (95% confidence interval [CI], 1,937-4,849) per 100,000 person-years compared to 219-231 per 100,000 person-years in the general population. Older age (odds ratio [OR], 1.02 [95% CI, 1.01-1.02] per year), males (OR, 1.25 [95% CI, 1.11-1.41), Chinese ethnicity (OR, 1.61 [95% CI, 1.37-1.89]) and a lower prevalence of hypertension (OR, 0.84 [95% CI, 0.73-0.97)]), and hyperlipidemia (OR, 0.53 [95% CI, 0.45-0.62]) were independently associated with cancer-related IS. Conclusions: The age-standardized cancer incidence was 15 times higher in IS patients than the general population. IS patients with concomitant cancer were older and had a lower prevalence of vascular risk factors.