1. In this study, a high CHA2DS2-VASc score in heart failure patients with or without atrial fibrillation was generally shown to correlate with a high absolute risk of mortality, blood clot, and stroke.
2. However, the CHA2DS2-VASc score demonstrated only moderate accuracy for predicting these endpoints in heart failure patients.
Evidence Rating Level: 2 (Good)
Study Rundown: Heart failure (HF) is a common medical disease and is often associated with atrial fibrillation (AF), an abnormal rhythm of the heart. It is well known that AF increases the risk of ischemic stroke and clinical risk scores have been devised to stratify patients based on their yearly risk for stroke. Heart failure is also an independent risk factor of stroke and mortality. This study asked the question of whether the simple clinical risk score (CHA2DS2-VASc) used to determine annual stroke risk in patients with AF is also able to risk-stratify patients with heart failure as well. The CHA2DS2-VASc score gives 2 points each for a history of prior thromboembolic event and for patients aged 75 years or older, and 1 point each for the presence of heart failure, hypertension, female gender, diabetes mellitus, vascular disease and being between the ages of 65 and 74 years.
Results showed that a high CHA2DS2-VASc score in heart failure patients with or without atrial fibrillation was generally shown to correlate with a high absolute risk of mortality, blood clot, and stroke. However, the accuracy of the CHA2DS2-VASc score for predicting these endpoints in heart failure patients was only moderate. Strengths of this study included the sample number and the lack of selection bias that is inherent to a retrospective cohort study using a national database. Weaknesses of the study included the lack of controlling for variables such as other co-morbidities besides cancer and COPD. Further studies are required to further explore the utility of the CHA2DS2-VASc score in heart failure patients.
In-Depth [retrospective cohort study]: This study utilized the Danish national registries to include all participants aged 50 years or older with a primary diagnosis of incident heart failure from 2000 to 2010, resulting in a study population of 42,987 patients, 88.1% of which had no diagnosis of atrial fibrillation at baseline. Patients with chronic obstructive pulmonary disease (COPD), cancer, or who have taken vitamin K antagonists in the past 6 months were excluded. Study results showed that a higher CHA2DS2-VASc score in HF patients with or without atrial fibrillation was generally shown to correlate with a high absolute risk of mortality, blood clot, and stroke (for a score of 1 vs 6, the absolute risk of ischemic stroke in HF+AF was 4.5% versus 8.4%, in HF no AF was 1.5% versus 7.0%; of mortality in HF+AF was 19.8% vs 45.5%, in HF no AF was 7.6% vs 35.0%; for blood clot in HF+AF was 9% vs 14.9%, in HF no AF was 5.3% vs 18.0%, respectively). However, the CHA2DS2-VASc score demonstrated only moderate accuracy for predicting these endpoints in heart failure patients with negative predictive values ranging from 88% (95%CI 87%-89%) for blood clot at 1 year in HF no AF, to 94% (95%CI 91%-97%) for death at 1 year in HF+AF.
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