Warfarin treatment and risk of stroke among primary care patients with atrial fibrillation

Abstract

Objective. Our aim was to study the risk of a first ischaemic stroke (IS) in patients with atrial fibrillation (AF) treated in primary healthcare. Design. The study population included all adults (n = 11,517), 45 years and older diagnosed with AF, from 75 primary care centres in Sweden between 2001 and 2007. IS was defined as a hospital care event of stroke between 2001 and 2010. Association between incident stroke and warfarin treatment was explored using Cox regression analysis, with hazard ratios (HRs), and 95% confidence intervals (95%CIs). Adjustment was made for age, socioeconomic factors and co-morbidity. Results. Persistent treatment with warfarin was present among 33.7% of women and 40.0% among men. Persistent warfarin treatment, compared to no persistent treatment, was associated with a stroke preventing effect with fully adjusted HRs of 0.25 (95%CI 0.18–0.36) in women, and 0.25 (95%CI 0.19–0.32) in men. A CHA₂DS₂-VASc score of at least two among women, and three among men, was associated with a stroke risk exceeding 18% during a mean follow-up of 5.4 years. Risk of haemorrhagic stroke was not increased. Conclusions. Warfarin is effective in preventing stroke in AF patients in primary healthcare.

Keywords:

• Atrial fibrillation
• ischaemic stroke
• gender
• follow-up
• co-morbidity
• anticoagulant

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Corrigendum

Acknowledgements

We thank Patrick Reilly for the professional linguist review.

Disclosure statement

The authors have no conflict of interest to disclose. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.