Laurent Azoulay1, Sophie Dell'Aniello2, Teresa A Simon3, Christel Renoux4, Samy Suissa5. 1. Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, 3755 Côte-Sainte-Catherine, H-461, Montreal, QC, Canada H3T 1E2 Department of Oncology, McGill University, Montreal, QC, Canada. 2. Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, 3755 Côte-Sainte-Catherine, H-461, Montreal, QC, Canada H3T 1E2. 3. Bristol-Myers Squibb, Princeton, NJ, USA. 4. Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, 3755 Côte-Sainte-Catherine, H-461, Montreal, QC, Canada H3T 1E2 Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada. 5. Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, 3755 Côte-Sainte-Catherine, H-461, Montreal, QC, Canada H3T 1E2 Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada samy.suissa@mcgill.ca.
Abstract
AIMS: An increased risk of stroke was observed in two atrial fibrillation (AF) trials of oral factor Xa inhibitors, when patients were transitioned to open label warfarin at the end of the study. The objective of this study is to determine whether initiation of warfarin is associated with an increased risk of stroke in patients with AF. METHODS AND RESULTS: Using the UK Clinical Practice Research Datalink, a nested case-control analysis was conducted within a cohort of 70 766 patients with AF between 1993 and 2008. Stroke cases were randomly matched with up to 10 controls on age, sex, date of AF diagnosis, and time since AF diagnosis. Conditional logistic regression was used to estimate adjusted rate ratios (RRs) with 95% confidence intervals (CIs) of stroke associated with current warfarin use classified according to time since initiation of treatment (<30 days, 31-90 days, and >90 days), when compared with non-use. A total of 5519 patients experienced a stroke during follow-up. Warfarin was associated with a 71% increased risk of stroke in the first 30 days of use (RR: 1.71, 95% CI: 1.39-2.12), while decreased risks were observed with initiation >30 days before the event (31-90 days: RR: 0.50, 95% CI: 0.34-0.75 and >90 days: RR: 0.55, 95% CI: 0.50-0.61, respectively). CONCLUSION: Patients initiating warfarin may be at an increased risk of stroke during the first 30 days of treatment, supporting the biological plausibility of a transient hypercoagulable state at the start of the treatment, although additional studies are needed to confirm these findings. Published on behalf of the European Society of Cardiology. All rights reserved.
AIMS: An increased risk of stroke was observed in two atrial fibrillation (AF) trials of oral factor Xa inhibitors, when patients were transitioned to open label warfarin at the end of the study. The objective of this study is to determine whether initiation of warfarin is associated with an increased risk of stroke in patients with AF. METHODS AND RESULTS: Using the UK Clinical Practice Research Datalink, a nested case-control analysis was conducted within a cohort of 70 766 patients with AF between 1993 and 2008. Stroke cases were randomly matched with up to 10 controls on age, sex, date of AF diagnosis, and time since AF diagnosis. Conditional logistic regression was used to estimate adjusted rate ratios (RRs) with 95% confidence intervals (CIs) of stroke associated with current warfarin use classified according to time since initiation of treatment (<30 days, 31-90 days, and >90 days), when compared with non-use. A total of 5519 patients experienced a stroke during follow-up. Warfarin was associated with a 71% increased risk of stroke in the first 30 days of use (RR: 1.71, 95% CI: 1.39-2.12), while decreased risks were observed with initiation >30 days before the event (31-90 days: RR: 0.50, 95% CI: 0.34-0.75 and >90 days: RR: 0.55, 95% CI: 0.50-0.61, respectively). CONCLUSION:Patients initiating warfarin may be at an increased risk of stroke during the first 30 days of treatment, supporting the biological plausibility of a transient hypercoagulable state at the start of the treatment, although additional studies are needed to confirm these findings. Published on behalf of the European Society of Cardiology. All rights reserved.
Authors: Bulent Gorenek; Antonio Pelliccia; Emelia J Benjamin; Giuseppe Boriani; Harry J Crijns; Richard I Fogel; Isabelle C Van Gelder; Martin Halle; Gulmira Kudaiberdieva; Deirdre A Lane; Torben Bjerregaard Larsen; Gregory Y H Lip; Maja-Lisa Løchen; Francisco Marin; Josef Niebauer; Prashanthan Sanders; Lale Tokgozoglu; Marc A Vos; David R Van Wagoner; Laurent Fauchier; Irina Savelieva; Andreas Goette; Stefan Agewall; Chern-En Chiang; Márcio Figueiredo; Martin Stiles; Timm Dickfeld; Kristen Patton; Massimo Piepoli; Ugo Corra; Pedro Manuel Marques-Vidal; Pompilio Faggiano; Jean-Paul Schmid; Ana Abreu Journal: Eur J Prev Cardiol Date: 2016-11-04 Impact factor: 7.804
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Authors: David R Van Wagoner; Jonathan P Piccini; Christine M Albert; Mark E Anderson; Emelia J Benjamin; Bianca Brundel; Robert M Califf; Hugh Calkins; Peng-Sheng Chen; Nipavan Chiamvimonvat; Dawood Darbar; Lee L Eckhardt; Patrick T Ellinor; Derek V Exner; Richard I Fogel; Anne M Gillis; Jeff Healey; Stefan H Hohnloser; Hooman Kamel; David A Lathrop; Gregory Y H Lip; Reena Mehra; Sanjiv M Narayan; Jeffrey Olgin; Douglas Packer; Nicholas S Peters; Dan M Roden; Heather M Ross; Robert Sheldon; Xander H T Wehrens Journal: Heart Rhythm Date: 2014-11-18 Impact factor: 6.343
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