Assessment of the CHA2DS2-VASc score in predicting ischemic stroke, thromboembolism, and death in patients with heart failure with and without atrial fibrillation

IMPORTANCE: The CHA2DS2-VASc score (congestive heart failure, hypertension, age ≥75 years [doubled], diabetes, stroke/transient ischemic attack/thromboembolism [doubled], vascular disease [prior myocardial infarction, peripheral artery disease, or aortic plaque], age 65-75 years, sex category [female]) is used clinically for stroke risk stratification in atrial fibrillation (AF). Its usefulness in a population of patients with heart failure (HF) is unclear.

OBJECTIVE: To investigate whether CHA2DS2-VASc predicts ischemic stroke, thromboembolism, and death in a cohort of patients with HF with and without AF.

DESIGN, SETTING, AND POPULATION: Nationwide prospective cohort study using Danish registries, including 42 987 patients (21.9% with concomitant AF) not receiving anticoagulation who were diagnosed as having incident HF during 2000-2012. End of follow-up was December 31, 2012.

EXPOSURES: Levels of the CHA2DS2-VASc score (based on 10 possible points, with higher scores indicating higher risk), stratified by concomitant AF at baseline. Analyses took into account the competing risk of death.

MAIN OUTCOMES AND MEASURES: Ischemic stroke, thromboembolism, and death within 1 year after HF diagnosis.

RESULTS: In patients without AF, the risks of ischemic stroke, thromboembolism, and death were 3.1% (n = 977), 9.9% (n = 3187), and 21.8% (n = 6956), respectively; risks were greater with increasing CHA2DS2-VASc scores as follows, for scores of 1 through 6, respectively: (1) ischemic stroke with concomitant AF: 4.5%, 3.7%, 3.2%, 4.3%, 5.6%, and 8.4%; without concomitant AF: 1.5%, 1.5%, 2.0%, 3.0%, 3.7%, and 7% and (2) all-cause death with concomitant AF: 19.8%, 19.5%, 26.1%, 35.1%, 37.7%, and 45.5%; without concomitant AF: 7.6%, 8.3%, 17.8%, 25.6%, 27.9%, and 35.0%. At high CHA2DS2-VASc scores (≥4), the absolute risk of thromboembolism was high regardless of presence of AF (for a score of 4, 9.7% vs 8.2% for patients without and with concomitant AF, respectively; overall P<.001 for interaction). C statistics and negative predictive values indicate that the CHA2DS2-VASc score performed modestly in this HF population with and without AF (for ischemic stroke, 1-year C statistics, 0.67 [95% CI, 0.65-0.68] and 0.64 [95% CI, 0.61-0.67], respectively; 1-year negative predictive values, 92% [95% CI, 91%-93%] and 91% [95% CI, 88%-95%], respectively).

CONCLUSIONS AND RELEVANCE: Among patients with incident HF with or without AF, the CHA2DS2-VASc score was associated with risk of ischemic stroke, thromboembolism, and death. The absolute risk of thromboembolic complications was higher among patients without AF compared with patients with concomitant AF at high CHA2DS2-VASc scores. However, predictive accuracy was modest, and the clinical utility of the CHA2DS2-VASc score in patients with HF remains to be determined.