Diabetes contributes to increased stroke risk independent of CAD

Diabetes mellitus (DM) carries an increased hazard of ischaemic stroke in patients with or without atrial fibrillation even in the absence of coronary artery disease (CAD), a study has found.

Researchers looked at a cohort of 81,909 patients who underwent coronary angiography, none of whom had been previously diagnosed with ischaemic stroke or transient ischaemic attack (TIA). Follow-up started 30 days after coronary angiography, and the median duration was 3.8 years.

In the cohort, 12,521 patients (15.3 percent) had diabetes, among whom 8,988 (11.0 percent) had CAD and 3,533 (4.3 percent) had no CAD. The respective number of those with and without CAD among patients without diabetes were 42,319 (51.7 percent) and 27,069 (33.0 percent).

Ischaemic stroke rates increased accordingly with the number of exposures, such that patients with neither CAD nor DM had the lowest risk (0.52 events per 100 person-years), those with CAD alone or DM alone had intermediate risk (0.77 and 0.95 events, respectively, per 100 person-years), and those with both DM and CAD had the highest risk (1.32 events per 100 person-years).

The adjusted incidence rate ratios for ischaemic stroke vs patients with neither DM nor CAD were 2.00 (95 percent confidence interval [CI], 1.72–2.32) in the group of patients with both DM and CAD, 1.27 (95 percent CI, 1.12–1.44) in the CAD-alone group and 1.74 (95 percent CI, 1.42–2.15) in the DM-alone group.

Among patients with DM, CAD extent further predicted the risk of ischaemic stroke (p-trend<0.001).

Results were similar for the composite endpoint of ischaemic stroke, TIA and systemic embolism, and did not differ between patients with and without AF.