We sought to evaluate the prognostic performance of the CHADS₂ score for prediction of ischemic stroke/transient ischemic attack (TIA) in subjects with coronary heart disease (CHD) without atrial fibrillation (AF).

In 916 nonanticoagulated outpatients with stable CHD and no AF by baseline electrocardiogram, we calculated CHADS₂ scores (congestive heart failure, hypertension, age ≥75 years, diabetes [1 point each], and prior stroke or TIA [2 points]). The primary outcome was time to ischemic stroke or TIA over a mean follow-up of 6.4 ± 2.3 years.

Over 5,821 person-years of follow-up, 40 subjects had an ischemic stroke/TIA (rate 0.69/100 person-years, 95% CI 0.50-0.94). Compared with subjects with low (0-1) CHADS₂ scores, those with intermediate (2-3) and high (4-6) CHADS₂ scores had an increased rate of stroke/TIA, even after adjustment for age, tobacco, antiplatelet therapy, statins, and angiotensin inhibitors (CHADS₂ score 2-3: HR 2.4, 95% CI 1.1-5.3, P = .03; CHADS₂ score 4-6: HR 4.0, 95% CI 1.5-10.6, P = .006). Model discrimination (c-statistic = 0.65) was comparable with CHADS₂ model fit in published AF-only cohorts.

The CHADS₂ score predicts ischemic stroke/TIA in subjects with stable CHD and no baseline AF. The event rate in non-AF subjects with high CHADS₂ scores (5-6) was comparable with published rates in AF patients with moderate CHADS₂ scores (1-2), a population known to derive benefit from stroke prevention therapies. These findings should inform efforts to determine whether stroke prevention therapies or screening for silent AF may benefit subjects with stable CHD and high CHADS₂ scores.