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Anticoagulation Use in Patients with Atrial Fibrillation


Tim Casey

San Francisco—Patients with atrial fibrillation (AF), providers, and health plans may benefit from utilizing software that identifies people who are at high risk of stroke, according to a descriptive, retrospective analysis of a comprehensive claims database.

The population studied typically does not receive appropriate medications, according to the authors. However, if patients with AF use anticoagulants, they can reduce their incidence of stroke as well as associated fatalities and morbidities. The adherence also leads to significant reductions in costs for patients and health plans.

The results were presented at the AMCP meeting in a poster titled Anticoagulants for Stroke Prophylaxis in a Commercially Insured Atrial Fibrillation Population.

The authors said thromboprophylaxis is the best way to prevent strokes in patients with AF, which is the most common chronic cardiac arrhythmia. Still, previous research found that only half of eligible patients with AF receive thromboprophylaxis.

In this study, the authors analyzed information from the PharMetrics® Integrated Database that included medical and pharmacy (retail and mail order) claims data from >70 million enrollees in >100 commercial insurers in the United States. They used the Anticoagulant Quality Improvement Analyzer (AQIA) software and identified patients meeting the following criteria: having records between July 2008 and June 2010 with a follow-up time of 12 months after the first AF diagnosis, ≥18 years of age, ≥1 primary or secondary AF diagnosis, and available pharmacy and medical claims.

To determine stroke risk, the authors used the CHADS2 (congestive heart failure, hypertension, age ≥75 years, diabetes, stroke/TIA) and CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes, stroke/TIA or thromboembolism- vascular disease, age 65-74 years, sex category female) schemes.

In the first measurement tool, patients get 1 point for each category with the exception of stroke/TIA, where they get 2 points. In the second measurement tool, patients get 1 point for each category with the exception of age ≥75 years and stroke/TIA or thromboembolism, where they get 2 points. Patients’ scores are tallied; a score of 0 points is classified as low risk, a score of 1 point is classified as moderate risk, and a score of ≥2 points is classified as high risk of developing a stroke.

The study included 25,710 patients with AF. The mean age was 71.6 years, and 58% were males. The majority of patients were identified as being at high risk of developing a stroke according to CHADS2 (54% of patients) and CHA2DS2-VASc (81% of patients).

Of the patients with AF, only 35% received anticoagulants during the study period. Of the patients at high risk for stroke according to CHADS2, 39% received anticoagulants compared with 34% of the moderate risk group and 27% of the low risk group. In addition, only 16% of the patients hospitalized for stroke received an anticoagulant before being admitted.

The authors cited several limitations. They used claims data, which may have been incomplete or inaccurate and do not reflect all clinical values that physicians use to make treatment decisions. They also did not identify over-the-counter medications such as aspirin. The stroke risk scores may have been underestimated because the researchers used a short time frame to identify risk-related events.

This study was funded by Janssen Scientific Affairs, LLC.

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