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Background: Catheter ablation (CA) is an established therapy for atrial fibrillation (AF). Studies regarding long-term real-world outcomes post-CA have inconsistently accounted for oral anticoagulation (OAC)., Objectives: To describe patterns of OAC use post-CA and to compare the OAC-adjusted long-term risk of stroke and major bleeding in AF patients with and without CA., Methods: A population-based cohort of AF patients was constructed in Quebec and Ontario, Canada (1999-2014). Propensity score matching was performed to determine the incidence rates of stroke and major bleeding among those undergoing CA, adjusted for time-dependent OAC use., Results: From the entire cohort, 6391 patients were identified as having undergone CA as compared to 482 977 patients who did not. Of these, 1240 patients with government medical insurance undergoing CA were matched with 2427 patients without CA. Post-CA, 78%, 65%, and 61% remained on an OAC at 1, 2, and 5 years, while 75%, 71%, and 68% of patients not undergoing CA were on OACs at 1, 2, and 5 years. At follow-up, there was no statistically significant difference for stroke (adjusted hazard ratio [HR], 0.88; 95% CI, 0.63 to 1.21) or major bleeding (adjusted HR, 0.88; 95% CI, 0.73 to 1.06)., Conclusion: No evidence was found that CA significantly decreases the risk of stroke or major bleeding when adjusting for OAC use over time. It may be prudent to continue anticoagulation post-CA based on patient-risk profile until randomized trials demonstrate both reduced stroke rates with CA, and improved safety (balancing stroke and bleeding risk) with OAC discontinuation post-CA., (© 2018 Wiley Periodicals, Inc.)

Objectives: The purpose of this study was to determine if anticoagulation of patients with new onset secondary atrial fibrillation (AF) occurring with acute coronary syndromes (ACS), acute pulmonary disease, or sepsis is associated with a reduction in ischemic stroke or an increase in bleeding risk., Background: Studies evaluating the benefits and risks of anticoagulation in secondary AF are infrequent, and the optimal management of these patients is not well understood., Methods: A retrospective study cohort was identified of 2,304 patients age 65 years or older, hospitalized with a primary diagnosis of ACS, acute pulmonary disease (chronic obstructive pulmonary disease, pneumonia/influenza, pulmonary embolism, or pleural effusion) or sepsis, and a complication of new-onset AF during admission from 1999 to 2015., Results: Over a follow-up of ∼3 years, we did not identify any association between anticoagulation and a lower incidence of ischemic stroke in patients with new-onset AF occurring with ACS, acute pulmonary disease, or sepsis (odds ratio [OR]: 1.22 [95% confidence interval (CI): 0.65 to 2.27], OR: 0.97 [95% CI: 0.53 to 1.77], and OR: 1.98 [95% CI: 0.29 to 13.47]), after adjusting for confounders. However, anticoagulation was associated with a higher risk of bleeding in patients with AF associated with acute pulmonary disease (OR: 1.72 [95% CI: 1.23 to 2.39]), but not in ACS or sepsis (OR: 1.42 [95% CI: 0.94 to 2.14], OR: 0.96 [95% CI: 0.29 to 3.21])., Conclusions: Our study demonstrates that the benefit of anticoagulation in secondary AF is not strong and can be associated with a higher risk of bleeding. Careful individual assessment regarding decisions on anticoagulation is warranted in these patients., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: Dabigatran and rivaroxaban are novel oral anticoagulants (NOACs) approved for stroke prevention in atrial fibrillation (AF). Although NOACs are more convenient than warfarin, their lack of monitoring may predispose patients to non-persistence. Limited information is available on NOAC non-persistence rates and related clinical outcomes in clinical practice., Methods: We conducted a retrospective cohort study using administrative data from Ontario, Canada, from January 1998 to March 2014 of patients with AF who were dispensed dabigatran or rivaroxaban. Non-persistence was defined as a gap in dabigatran or rivaroxaban prescriptions ≥14 days. A multivariable Cox proportional hazards model was used to estimate the primary composite outcome of stroke, transient ischaemic attack (TIA) and mortality associated with non-persistence., Results: The cohort consisted of 15 857 dabigatran (age 80.7±6.7 year) and 10 119 rivaroxaban users (age 77.0±7.1 year) with women comprising 52% of each medication group. At 6 months, 36.4% of patients were non-persistent to dabigatran, while 31.9% of patients were non-persistent to rivaroxaban. Stroke/TIA/death was significantly higher for those non-persistent to dabigatran (HR 1.76 (95% CI 1.60 to 1.94); p<0.0001) or rivaroxaban (HR 1.89 (95% CI 1.64 to 2.19); p<0.0001) compared with those who were persistent. Risk of stroke/TIA was markedly higher in non-persistent patients to dabigatran (HR 3.75 (95% CI 2.59 to 5.43); p<0.0001) and rivaroxaban (HR 6.25 (95% CI 3.37 to 11.58); p<0.0001) than those persistent., Conclusions: NOAC non-persistence rates are high in clinical practice, with approximately one in three patients becoming non-persistent to dabigatran or rivaroxaban within 6 months after drug initiation. Non-persistence with either dabigatran or rivaroxaban is significantly associated with worse clinical outcomes of stroke/TIA/death., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

In elderly patients (≥ 75 years), evidence of dabigatran efficacy is lacking and increased vigilance is warranted. We aimed to assess dabigatran effectiveness and safety in elderly patients in real-world practice. We conducted a population-based study using administrative databases, in Quebec (1999-2013). Dabigatran users (110/150 mg) were compared with matched warfarin users with regard to stroke and bleeding events. Age was categorised into < 75 or ≥ 75 years. Propensity score adjusted models were used. The cohort consisted of 15,918 dabigatran users and 47,192 matched warfarin users, with 67.3% being elderly patients. The elderly predominantly used the lower dose (80.1%) while younger patients mainly used the higher dose (80.0%). In multivariable analyses adjusted for propensity score, the risk of stroke in elderly patients using dabigatran, was no different than the risk in warfarin users (HR 1.05, 95% CI: 0.93, 1.19) regardless of dabigatran dose. However, dabigatran was associated with lower rates of intracranial haemorrhage (HR 0.60, 95% CI: 0.47-0.76) and higher rates of gastrointestinal bleeding (HR 1.30 95% CI: 1.14-1.50) when compared to warfarin. Based on real-life experience, dabigatran can offer an alternative to warfarin in elderly patients, with fewer intracranial bleeding events. However, caution is warranted for gastrointestinal bleeding.

Background: Current observational studies on warfarin use and the risk for stroke and bleeding in patients with atrial fibrillation (AF) undergoing dialysis found conflicting results., Methods and Results: We conducted a population-based retrospective cohort study of patients aged ≥65 years admitted to a hospital with a primary or secondary diagnosis of AF, in Quebec and Ontario, Canada from 1998 to 2007. The AF cohort was grouped into dialysis (hemodialysis and peritoneal dialysis) and nondialysis patients and into warfarin and no-warfarin users according to the first prescription filled for warfarin within 30 days after AF hospital discharge. We determined the association between warfarin use and the risk for stroke and bleeding in dialysis and nondialysis patients. The cohort comprised 1626 dialysis patients and 204 210 nondialysis patients. Among dialysis patients, 46% (756/1626) patients were prescribed warfarin. Among dialysis patients, warfarin users had more congestive heart failure and diabetes mellitus, but fewer prior bleeding events in comparison with the no-warfarin users. Among dialysis patients, warfarin use, in comparison with no-warfarin use, was not associated with a lower risk for stroke (adjusted hazard ratio, 1.14; 95% confidence interval, 0.78-1.67) but was associated with a 44% higher risk for bleeding (adjusted hazard ratio, 1.44; 95% confidence interval, 1.13-1.85) after adjusting for potential confounders. Propensity score-adjusted analyses yielded similar results., Conclusions: Our results suggest that warfarin use is not beneficial in reducing stroke risk, but it is associated with a higher bleeding risk in patients with AF undergoing dialysis.

Background: Novel therapies for anticoagulation and rhythm control for atrial fibrillation (AF) have been developed recently. To best evaluate the comparative effectiveness of newer agents, practice patterns and outcomes of existing therapies must be characterized at the population level., Methods: We conducted a retrospective population-based cohort study of patients ≥ 65 years with a first diagnosis of AF over a 9-year period in Québec and Ontario. Using hospital and drug claims databases, trends of filled prescriptions, and rates of strokes, bleeding complications, and mortality within 1 year were estimated., Results: From 1998 to 2006, 338, 479 patients were hospitalized with an AF diagnosis. Median age was 77.5 years and 50.4% were male. Use of rate control was 3-fold higher than rhythm control therapy. There was a modest decrease in rate control therapy until 2001 (71.9% to 70.6%, P = 0.01), followed by a progressive increase (70.6% to 76.4%, P = 0.014). An opposite trend was observed for rhythm control. Although warfarin prescriptions increased (51.0% to 64.5%, P < 0.0001), stroke rates tended to decrease (3.8% to 3.5%, P = 0.148). Bleeding complications increased mostly because of emergency room visits (4.8% to 6.1%, P = 0.007). Mortality remained high despite a small but statistically significant decline (27.6% to 25.8%, P = 0.018)., Conclusions: With increased anticoagulation use, stroke rates are declining and emergency room bleeding complications are increasing. Despite an increased use of evidence-based AF therapies, mortality remains high in this population. These findings highlight the need to focus on AF prevention in addition to minimizing its complications., (Copyright © 2013 Canadian Cardiovascular Society. All rights reserved.)

Background: Stroke is a debilitating condition with an increased risk in patients with atrial fibrillation. Although data from clinical trials suggest that both rate and rhythm control are acceptable approaches with comparable rates of mortality in the short term, it is unclear whether stroke rates differ between patients who filled prescriptions for rhythm or rate control therapy., Methods and Results: We conducted a population-based observational study of Quebec patients ≥65 years with a diagnosis of atrial fibrillation during the period 1999 to 2007 with the use of linked administrative data from hospital discharge and prescription drug claims databases. We compared rates of stroke or transient ischemic attack (TIA) among patients using rhythm (class Ia, Ic, and III antiarrhythmics), versus rate control (β-blockers, calcium channel blockers, and digoxin) treatment strategies (either current or new users). The cohort consisted of 16 325 patients who filled a prescription for rhythm control therapy (with or without rate control therapy) and 41 193 patients who filled a prescription for rate control therapy, with a mean follow-up of 2.8 years (maximum 8.2 years). A lower proportion of patients on rhythm control therapy than on rate control therapy had a CHADS(2) (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, and previous stroke or TIA) score of ≥2 (58.1% versus 67.0%, P<0.001). Treatment with any antithrombotic drug was comparable in the 2 groups (76.8% in rhythm control versus 77.8% in rate control group). Crude stroke/TIA incidence rate was lower in patients treated with rhythm control in comparison with rate control therapy (1.74 versus 2.49, per 100 person-years, P<0.001). This association was more marked in patients in the moderate- and high-risk groups for stroke according to the CHADS(2) risk score. In multivariable Cox regression analysis, rhythm control therapy was associated with a lower risk of stroke/TIA in comparison with rate control therapy (adjusted hazard ratio, 0.80; 95% confidence interval, 0.74, 0.87). The lower stroke/TIA rate was confirmed in a propensity score-matched cohort., Conclusions: In comparison with rate control therapy, the use of rhythm control therapy was associated with lower rates of stroke/TIA among patients with atrial fibrillation, in particular, among those with moderate and high risk of stroke.

Context: Stroke is a serious complication associated with atrial fibrillation (AF). Women with AF are at higher risk of stroke compared with men. Reasons for this higher stroke risk in women remain unclear, although some studies suggest that undertreatment with warfarin may be a cause., Objective: To compare utilization patterns of warfarin and the risk of subsequent stroke between older men and women with AF at the population level., Design, Setting, and Patients: Population-based cohort study of patients 65 years or older admitted to the hospital with recently diagnosed AF in the province of Quebec, Canada, 1998-2007, using administrative data with linkage between hospital discharge, physicians, and prescription drug claims databases., Main Outcome Measures: Risk of stroke., Results: The cohort comprised 39,398 men (47.2%) and 44,115 women (52.8%). At admission, women were older and had a higher CHADS(2) (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke or transient ischemic attack) score than men (1.99 [SD, 1.10] vs 1.74 [SD, 1.13], P < .001). At 30 days postdischarge, 58.2% of men and 60.6% of women had filled a warfarin prescription. In adjusted analysis, women appeared to fill more warfarin prescriptions compared with men (odds ratio, 1.07 [95% CI, 1.04-1.11]; P < .001). Adherence to warfarin treatment was good in both sexes. Crude stroke incidence was 2.02 per 100 person-years (95% CI, 1.95-2.10) in women vs 1.61 per 100 person-years (95% CI, 1.54-1.69) in men (P < .001). The sex difference was mainly driven by the population of patients 75 years or older. In multivariable Cox regression analysis, women had a higher risk of stroke than men (adjusted hazard ratio, 1.14 [95% CI, 1.07-1.22]; P < .001), even after adjusting for baseline comorbid conditions, individual components of the CHADS(2) score, and warfarin treatment., Conclusion: Among older patients admitted with recently diagnosed AF, the risk of stroke was greater in women than in men, regardless of warfarin use.