Author + information
- Tatjana S. Potpara, MD, PhD∗ ( )( and )
- Jonas B. Olesen, MD, PhD
- ↵∗School of Medicine, Belgrade University, Cardiology Clinic, Clinical Centre of Serbia, Visegradska 26, 11000 Belgrade, Serbia
Van den Ham et al. (1) recently compared the ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation), CHADS2 (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke or transient ischemic attack), and CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke or transient ischemic attack, vascular disease, age 65 to 74 years, female) stroke risk scores in a primary care community cohort of patients with first-diagnosed atrial fibrillation (AF) not using oral anticoagulation (OAC) for undefined reasons. They concluded that improved risk prediction using the ATRIA score can reduce OAC overuse in low-risk patients.
However, the study raises major concerns. To put their findings of a 2.99% annualized rate of stroke (excluding transient ischemic attack and systemic embolism) in appropriate context requires a better characterization of the cohort (e.g., a description of on-OAC patients from the dataset). Also, because the median follow-up was only 0.74 years over a 15-year study period and patients were censored if given OAC, the OAC prescription rate should have been shown.
The contemporary threshold for OAC use with non-OACs can reasonably be decreased to an annual stroke risk of approximately 1% (2). Using ATRIA in the aforementioned study, 40% of patients were categorized as low-risk (i.e., an ATRIA score ≤5, with annualized stroke rates of 0.40% to 1.99%), meaning that, for example, even a 74-year-old female with diabetes mellitus (i.e., 5 points) would not need OAC, nor would a 64-year-old male with hypertension and heart failure (2 points). However, a large body of evidence shows a positive net clinical benefit from OAC in such AF patients with ≥1 stroke risk factors (3).
Their sensitivity analysis excluding renal dysfunction shows an unchanged performance of ATRIA, thus suggesting that the improvement in discriminatory ability over CHA2DS2-VASc might be driven solely by the inclusion of more age categories. However, if the ATRIA “low-risk” category is restricted to stroke rates of <1% (ATRIA 0 to 2), all patients age ≥65 years would have a score ≥3 and would be given OAC, which again challenges the necessity of introducing additional age strata at the cost of simplicity.
Similarly, the clinical utility of further detailed risk stratification of AF patients with prior stroke with different weights and score points (as proposed by the ATRIA score) is questionable, given that prior stroke is the most powerful single risk factor for recurrent stroke, and such patients should be given OAC without further risk stratification.
To work in a busy clinical practice, a clinical risk score needs to be simple, user-friendly, and practical. Risk scores are also meant to be reductionist to help therapeutic decision-making (i.e., anticoagulate or not); the CHA2DS2-VASc score allows the initial identification of “low-risk” AF patients who do not need any antithrombotic therapy, following which OAC can be considered for those with ≥1 stroke risk factor.
Please note: Dr. Potpara has received consultancy and speaker fees from Bayer, Pfizer, and Boehringer Ingelheim. Dr. Olesen has received speaker fees from Bristol-Myers Squibb and Boehringer Ingelheim; and has received funding for research from Bristol-Myers Squibb.
- 2016 American College of Cardiology Foundation
- van den Ham H.A.,
- Klungel O.H.,
- Singer D.E.,
- Leufkens H.G.,
- van Staa T.P.
- Eckman M.H.,
- Singer D.E.,
- Rosand J.,
- Greenberg S.M.