Diabetes mellitus is associated with increased risk of ischemic stroke in patients with and without coronary artery disease

Abstract

Background and Purpose-Diabetes mellitus (DM) and non-DM patients without coronary artery disease (CAD) havea similar low risk of myocardial infarction after coronary angiography. The risk of ischemic stroke in DM patientsdependent on CAD status is less explored. We examined whether DM patients without CAD have a risk of ischemicstroke similar to that in patients with neither DM nor CAD.Methods-We conducted a cohort study of patients who underwent coronary angiography between 2004 and 2012 inWestern Denmark. Patients diagnosed with previous ischemic stroke or transient ischemic attack were excluded. Patientswere stratified according to the presence of DM and CAD. Follow-up started 30 days after coronary angiography. Wecomputed event rates and adjusted incidence rate ratios using patients without DM or CAD as reference. We examinedthe trend between CAD extent and ischemic stroke in patients with DM.Results-A total of 81 909 patients were included. Median follow-up was 3.8 years. Patients with both DM and CAD wereat the highest risk of ischemic stroke (1.32 events per 100 person-years; adjusted incidence rate ratio, 2.00 [95% CI,1.72-2.32]). Patients with CAD alone (0.77 events per 100 person-years; adjusted incidence rate ratio, 1.27 [95% CI,1.12-1.44]) or DM alone (0.95 events per 100 person-years; adjusted incidence rate ratio, 1.74 [95% CI, 1.42-2.15]) wereat intermediate risk, whereas patients with neither DM nor CAD (0.52 events per 100 person-years) were at the lowestrisk. Among patients with DM, extent of CAD was further predictive of risk (Ptrend<0.001).Conclusions-Not only CAD but also DM are associated with the risk of ischemic stroke after coronary angiography. Theircombination further increases the risk of ischemic stroke depending on the extent of CAD.