What is the clinical evidence from this study?

Study design: Observational. Population: Atrial fibrillation with low CHADS2 score (n=346068). Intervention: CHA2DS2-VASc score adoption vs. CHADS2 score. Primary outcome: Proportion of patients with an indication for OAC and trends in OAC prescription (OR 2.07, 95% CI 1.97-2.19).

May 1, 2017Open Access

Contemporary Trends in Oral Anticoagulant Prescription in Atrial Fibrillation Patients at Low to Moderate Risk of Stroke After Guideline-Recommended Change in Use of the CHADS 2 to the CHA 2 DS 2 -VASc Score for Thromboembolic Risk Assessment

Key Result

Adoption of the CHA2DS2-VASc score reclassified 64.5% of AF patients with low CHADS2 scores into a class I indication for OAC, with overall OAC prescription increasing from 37% to 48%.

Study Design

Type

Observational (n=346,068)

Multicenter

Yes

Structured PICO

Does the adoption of the CHA2DS2-VASc score increase the proportion of AF patients with low CHADS2 scores who qualify for and receive oral anticoagulation?

Population

346,068 patients with atrial fibrillation and a CHADS2 score of 0 or 1 enrolled in the American College of Cardiology National Cardiovascular Data Registry's outpatient Practice Innovation and Clinical Excellence registry (2008–2014), mean age 65±12 years, 61% men, 65% white.

Intervention

Application of the CHA2DS2-VASc score for thromboembolic risk assessment

Comparator

CHADS2 score

Outcome

Proportion of patients reclassified as having a definite indication for oral anticoagulation (CHA2DS2-VASc score ≥2) and trends in oral anticoagulant prescription

The transition from CHADS2 to CHA2DS2-VASc scoring significantly increased the proportion of AF patients with a class I indication for OAC, accompanied by an increase in actual OAC prescriptions in contemporary practice.

Main Result

Effect estimate: OR 2.07 (95% CI 1.97-2.19)

Abstract

Background— Use of the CHA 2 DS 2 -VASc score instead of the CHADS 2 score for thromboembolic risk stratification and initiation of oral anticoagulation (OAC) was recommended in the 2014 American Heart Association/American College of Cardiology/Heart Rhythm Society atrial fibrillation (AF) guidelines. We sought to define the proportion of patients with AF qualifying for and receiving OAC in contemporary practice by applying the CHA 2 DS 2 -VASc score to patients with a low CHADS 2 score. Methods and Results— Among patients with AF enrolled in the American College of Cardiology National Cardiovascular Data Registry’s outpatient Practice Innovation and Clinical Excellence registry (2008–2014) CHADS 2 score of 0 or 1, we calculated the impact of adoption of the CHA 2 DS 2 -VASc score on the proportion of patients with an indication for OAC. We examined trends in prescription of OAC overall, direct OAC (dabigatran/rivaroxaban/apixaban), and multivariable associations between clinical characteristics and OAC use. Of 346 068 patients with AF aged 65±12 years, 61% were men and 65% were white. In total, 24% of those with CHADS 2 =0 and 81% of those with a CHADS 2 =1 were reclassified as having a definite indication for OAC (CHA 2 DS 2 -VASc score ≥2). OAC use increased from 37% to 48% during the study period, and direct OAC use increased from 5% to 30%. Increasing CHA 2 DS 2 -VASc score (odds ratio, 2.07; 95% confidence interval, 1.97–2.19 for score of 4 versus 0) and rhythm control strategy (odds ratio, 1.34; 95% confidence interval, 1.30–1.39) were associated with increased OAC use. Conclusions— Adoption of the CHA 2 DS 2 -VASc score reclassifies 64.5% of patients with AF with low CHADS 2 scores into a class I indication for OAC prescription. Overall OAC prescription increased between 2011 and 2014.