Cardiac complications are common after ischemic stroke. Although causality cannot be implied from our study design, we hypothesized that if cardiovascular events are explained by a prior stroke, we should at least find an association between ischemic stroke and incident cardiovascular events.

To assess whether first-ever ischemic stroke is independently associated with the incident risk of cardiovascular events.

This population-based retrospective cohort study included residents in Ontario between 04/01/2002 and 03/31/2012, aged ≥65 years, without prior cardiovascular disease. We compared the incident risk of cardiovascular events defined as the composite of myocardial infarction, unstable angina, congestive heart failure, newly diagnosed coronary artery disease, or coronary artery revascularization at 1 year in patients with a first-ever ischemic stroke (exposure group) relative to propensity-matched individuals without stroke history (control group). We performed 3x1 propensity matching for 31 variables including demographics, socioeconomic status, risk factors, comorbidities, medications, and hospitalizations in the prior year. We applied a marginal cause-specific Cox regression model adjusted for age, sex, and stroke or transient ischemic attack during follow-up for estimating the risk of incident cardiovascular events. We treated stroke and transient ischemic attack during follow-up as a time-varying covariate and non-cardiac death as a competing risk.

We included 21,931 patients with incident ischemic stroke and 71,696 propensity matched individuals without stroke history. Median age was 76 (71-81) years and 57% were females. The cohort was well-balanced on all variables used for propensity matching (weighted differences ≤5%). At 1 year, there were 1,361 (6.21%) outcome events among stroke patients and 1,286 (1.79%) among controls. At time 0, first-ever ischemic stroke was associated with higher risk of incident cardiovascular events (HR 10.4, 95%CI 9.2-11.8), which declined by 0.7%/day thereafter.

In this large population based study, ischemic stroke was independently associated with a 10-fold increased risk of incident cardiovascular events.