Is the CHA2-DS2-VASc Score Consistent in Predicting Clinical Outcomes in AF and Flutter?

The CHA₂-DS₂-VASc Scoring system began in 2010 to predict the risk of thromboembolic events in atrial flutter and fibrillation.¹ The system additionally has been used to stratify the risk of heart failure hospitalization and mortality in these patients.^2-3  However, does the CHA₂-DS₂-VASc Score system equivalently predict outcomes in atrial flutter and fibrillation?

A recently published 11-year cohort study of 219,416 age- and sex-matched individuals from the Taiwan National Health Insurance Research Database studied ischemic stroke, heart failure hospitalization, and all-cause mortality differences between atrial flutter and atrial fibrillation sheds some light on this question.⁴ The investigators studied 6121 atrial flutter and 188,811 atrial fibrillation unique patients compared with 24,484 age- and sex-matched controls.  Compared with atrial flutter and controls, atrial fibrillation patients were older, more likely female, and had higher CHA₂-DS₂-VASc Scores.  The incidence densities for ischemic stroke were 3.08 (95% CI: 3.03-3.13), 1.45 (95% CI: 1.28-1.62), and 0.97 (95% CI: 0.92-1.03) for atrial fibrillation, atrial flutter, and controls, respectively.  For heart failure and all-cause mortality outcomes, the incidence density was higher for atrial fibrillation compared to atrial flutter and controls.  When the CHA₂-DS₂-VASc Score was between ≥ 1 points, the incidences of ischemic stroke and heart failure hospitalization were higher for both atrial fibrillation as compared to atrial flutter.  All-cause mortality also had higher in atrial fibrillation versus atrial flutter when CHA₂-DS₂-VASc Score was between 1-to-3. The study used a retrospective design with multiple insurance databases to generate the data, thereby limiting the findings.

These findings suggest that the CHA₂-DS₂-VASc Score may need further research before it can be used to support the routine prescribing of oral anticoagulants in atrial flutter. 

Mark A. Munger, PharmD, FCCP, FACC, is a professor of pharmacotherapy and adjunct professor of internal medicine, at the University of Utah, where he also serves as the associate dean of Academic Affairs for the College of Pharmacy.  

References:

1. Lip GY, Nieuwlaat R, Pisters R, Lane DA, Crijns HJ. Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation using a novel risk factor-based approach: The Euro Heart Survey on Atrial Fibrillation.  Chest 1020;137(2):263-72.
2. Asawat S, Tangcharoen T, Wisaratapong T, Yamwong S, Wiboonpolprasert S, Sritara P. CHA₂-DS₂-VASc Scores predict mortality after hospitalization for atrial fibrillation. Int J Cardiol 2015;185:293-6.
3. Naccarelli GY, Panaccio MP, Cummins G, Tu N. CHADS₂ and CHA₂-DS₂-VdASc Score risk factors to predict first cardiovascular hospitalization among atrial fibrillation/atrial flutter patients. Am J Cardiol 2012;109(10):1526-33.