Response by Nielsen and Lip to Letter Regarding Article, “Should Patients With Atrial Fibrillation and 1 Stroke Risk Factor (CHA <sub>2</sub> DS <sub>2</sub> -VASc Score 1 in Men, 2 in Women) Be Anticoagulated? Yes: Even 1 Stroke Risk Factor Confers a Real Risk of Stroke”
Authors: Peter Brønnum Nielsen, Gregory Y. H. Lip
Journal: Circulation (2016)

In Response:We thank Dr Asinger et al for their comments.On whether or not to provide oral anticoagulant treatment in atrial fibrillation (AF) patients with 1 stroke risk factor, we advocated our viewpoint by using contemporary data from various sources.These data convincingly suggest that AF patients with a CHA 2 DS 2 -VASc score 1 (or 2 in women) benefit from oral anticoagulant (OAC) treatment. 1he point made by Dr Asinger of declining stroke rates in AF populations during the past decades are based on selected populations (eg, Framingham-and Medicare-enrolled patients) that might not generalize into a broader unselected nationwide AF patient population.No trend of change was observed when we investigated the ischemic stroke rates in all hospitalized AF patients in Denmark between 1998 and 2012, even in those untreated and with no or 1 additional risk factor. 2 Cutoff values for treatment recommendation of OAC treatment initiation based on the CHA 2 DS 2 -VASc score and methodology are important. 3If data are not appropriately analyzed, observed event rates will differ markedly, especially in analyses where any OAC-initiated patients are excluded, thus resulting in conditioning on the future and biasing event rates toward lower values.We have shown that when person-time was appropriately censored at the time of OAC initiation, we obtained ischemic stroke rates of 1.53%/y for AF patients with a CHA 2 DS 2 -VASc=1 (men) and 2.33%/y for those with a CHA 2 DS 2 -VASc=2 (men and women).In addition to the main analysis, a sensitivity analysis of different time periods did not affect the outcomes.In the French Loire Valley AF Project using data from 2000 to 2010, Fauchier et al 4 observed a stroke rate of 2.09%/y in AF patients with 1 non-sex-related stroke risk factor, and a significant excess of mortality, as well; importantly, there was a positive net clinical benefit of OAC in comparison with being untreated or taking aspirin.Aspirin use had a negative net clinical benefit in comparison with being left untreated.Patients greatly value stroke prevention, and, to prevent 1 stroke (which is regarded as a fate worse than death), they are prepared even to sustain 4 major bleeds. 5The consistency of most data from different contemporary cohorts clearly shows that even 1 stroke risk factor confers an appreciable risk of stroke (and AF-related strokes are more likely to be fatal and severely disabling) and mortality, and that OAC use results in a positive net clinical benefit in comparison with leaving such patients untreated or on aspirin.Is it really worth taking the risk of leaving such AF patients untreated? DISCLOSURESDr Lip: Guideline membership/reviewing for various guidelines and position statements from ESC, EHRA, NICE etc. Steering Committees/trials: Includes steering committees for various Phase II and III studies, Health Economics & Outcomes Research, etc. Investigator in various clinical trials in cardiovascular disease, including those on antithrombotic therapies in atrial fibrillation, acute coronary syndrome, lipids, etc. Consultant for Bayer, Janssen J&J, Astel-