Use of oral anticoagulants in atrial fibrillation is highly variable and only weakly associated with estimated stroke...

Area of Science:

• Cardiology
• Primary Care Medicine
• Pharmacoeconomics

Background:

• International guidelines recommend stroke risk stratification tools for oral anticoagulant (OAC) decisions in atrial fibrillation (AF).
• Existing tools like CHADS2 and CHA2DS2VASc aim to guide OAC prescribing to prevent stroke in AF patients.

Purpose of the Study:

• To compare stroke risk classification between CHADS2 and CHA2DS2VASc in primary care AF patients.
• To analyze antithrombotic prescribing patterns relative to stroke risk.
• To identify patient and practice factors associated with OAC use in AF.

Main Methods:

• A cross-sectional study utilized multilevel modeling.
• Data included 21,564 AF patients from 315 Scottish General Practices, excluding those with rheumatic heart disease or valve replacement.
• Analysis focused on risk score differences, antithrombotic use, and associated patient/practice characteristics.

Main Results:

• CHA2DS2VASc classified significantly more patients as high-risk (85.1%) compared to CHADS2 (53.8%).
• 17.8% of patients received no antithrombotics, while 43.3% were on OAC; OAC use showed weak correlation with stroke risk.
• Factors like paroxysmal AF, dementia, and peptic ulcers were linked to lower OAC likelihood. OAC prescribing varied significantly between practices, with remote and non-training practices more likely to prescribe OAC.

Conclusions:

• Evidence suggests both underuse and overuse of OACs in AF patients.
• While risk stratification tools are plausible for improving decision-making, their real-world impact on OAC prescribing and patient outcomes requires evaluation.
• Pragmatic trials are needed to assess the effectiveness of these tools in clinical practice.