Stroke and Bleeding Risk Associated With Antithrombotic Therapy for Patients With Nonvalvular Atrial Fibrillation in...

Area of Science:

• Cardiology
• Pharmacology
• Public Health

Background:

• Suboptimal antithrombotic therapy is common in nonvalvular atrial fibrillation (NVAF) patients.
• Limited evidence exists linking stroke and bleeding risks with specific antithrombotic treatments.
• This study evaluates antithrombotic treatment outcomes in NVAF patients.

Purpose of the Study:

• To assess the association between antithrombotic therapy episodes and clinical outcomes in NVAF patients.
• To compare stroke, systemic embolism (SE), and major bleeding risks across different treatment strategies.
• To determine the impact of warfarin time in therapeutic range (TTR) on patient outcomes.

Main Methods:

• Retrospective longitudinal observational cohort study.
• Included NVAF patients with stroke risk factors (CHADS2 ≥1) from Kaiser Permanente Southern California (2006-2011).
• Analyzed 1782 stroke/SE events and 3528 major bleed events over 60,021 person-years.

Main Results:

• Warfarin episodes with TTR ≥55% showed the lowest stroke/SE (0.87/100 person-years) and major bleed rates (4.91/100 person-years).
• Warfarin TTR ≥55% was associated with a 77% lower stroke/SE risk compared to no therapy.
• Warfarin TTR <55% increased major bleed risk nearly twofold versus no therapy, while aspirin use showed a 26% lower stroke/SE risk.

Conclusions:

• Continuing antithrombotic therapy is crucial for stroke prevention in NVAF.
• Achieving and maintaining adequate warfarin TTR (≥55%) is beneficial for minimizing bleeding events.
• Optimal TTR management improves NVAF patient outcomes by balancing efficacy and safety.