The CHADS2 score predicts ischemic stroke in the absence of atrial fibrillation among subjects with coronary heart disease: data from the Heart and Soul Study

Abstract

Background: We sought to evaluate the prognostic performance of the CHADS(2) score for prediction of ischemic stroke/transient ischemic attack (TIA) in subjects with coronary heart disease (CHD) without atrial fibrillation (AF).

Methods: In 916 nonanticoagulated outpatients with stable CHD and no AF by baseline electrocardiogram, we calculated CHADS(2) 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.

Results: 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) CHADS(2) scores, those with intermediate (2-3) and high (4-6) CHADS(2) scores had an increased rate of stroke/TIA, even after adjustment for age, tobacco, antiplatelet therapy, statins, and angiotensin inhibitors (CHADS(2) score 2-3: HR 2.4, 95% CI 1.1-5.3, P = .03; CHADS(2) score 4-6: HR 4.0, 95% CI 1.5-10.6, P = .006). Model discrimination (c-statistic = 0.65) was comparable with CHADS(2) model fit in published AF-only cohorts.

Conclusions: The CHADS(2) score predicts ischemic stroke/TIA in subjects with stable CHD and no baseline AF. The event rate in non-AF subjects with high CHADS(2) scores (5-6) was comparable with published rates in AF patients with moderate CHADS(2) 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 CHADS(2) scores.

Figure 1

Rate of ischemic stroke/TIA, by CHADS2 score

Figure 2

Kaplan Meier curves for survival free of ischemic stroke/TIA, stratified by CHADS2 score