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Aims: To examine the risk of arterial thromboembolism, bleeding, and all-cause mortality in atrial fibrillation (AF) patients treated with direct oral anticoagulants (DOACs) vs. vitamin K antagonists (VKAs) undergoing transcatheter aortic valve implantation (TAVI)., Methods and Results: In this nationwide observational cohort study, 735 patients undergoing TAVI from 1 January 2012 to 30 June 2017 with a history of AF and who were treated with oral anticoagulants were identified using data from Danish nationwide registries. Of these, 219 (29.8%) and 516 (70.2%) patients were treated with DOACs and VKAs, respectively. The DOAC group was characterized by a higher prevalence of previous arterial thromboembolism and a lower prevalence of chronic kidney disease compared with the VKA group. The distribution of age, sex, CHA2DS2-VASc and HAS-BLED scores, and concomitant antiplatelet therapy was similar between groups. Compared with VKA, treatment with DOACs was not associated with a significantly different 3-year absolute risk of arterial thromboembolism [9.6% (95% confidence interval, CI 4.7-16.5%) vs. 7.4% (95% CI 4.9-10.5%) in the DOAC and VKA group, respectively], bleeding [14.3% (95% CI 7.6-22.9%) vs. 13.3% (95% CI 9.9-17.1%)], or all-cause mortality [32.7% (95% CI 21.8-44.0%) vs. 32.0% (95% CI 26.8-37.3%)]. In adjusted analyses, treatment with DOACs, when compared with VKAs, was not associated with a significantly different rate of arterial thromboembolism [hazard ratio (HR) 1.23 (95% CI 0.58-2.59)], bleeding [HR 1.14 (95% CI 0.63-2.06)], or all-cause mortality [HR 0.93 (95% CI 0.61-1.40)]., Conclusion: In patients with AF undergoing TAVI, treatment with DOACs was not associated with a significantly different risk of arterial thromboembolism, bleeding, or all-cause mortality compared with VKA., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Aims: Non-vitamin K antagonist oral anticoagulants (NOACs) are displacing vitamin K antagonists (VKAs) for stroke prophylaxis in patients with atrial fibrillation (AF). Concomitant use of non-steroidal anti-inflammatory drugs (NSAIDs) could increase gastrointestinal bleeding (GIB) risks among these patients. The aim of this study was to examine the risk of GIB among Danish AF patients taking oral anticoagulants (OACs) and NSAIDs., Methods and Results: Using nationwide administrative registries, we determined concomitant NSAID use among anticoagulant-naïve patients with AF initiating OACs between August 2011 and June 2017. We calculated short-term absolute risks differences and hazard ratios (HRs) for GIB based on multiple adjusted cause-specific Cox regressions with time-dependent NSAID treatment. Among 41 183 patients [median age 70 years (interquartile range 64-78); 55% men], 21% of patients on NOACs and 18% on VKA were co-prescribed NSAIDs. The differences in absolute risk [95% confidence interval (CI)] of GIB within 14 days of commencing concomitant NSAID therapy (vs. no concomitant NSAID therapy) were 0.10% (0.04-0.18%) for NOACs and 0.13% (0.03-0.24%) for VKA. NOACs overall were associated with less GIB than VKA [HR 0.77 (95% CI 0.69-0.85)]. Compared with OACs alone, concomitant NSAIDs doubled the GIB risk associated with NOACs overall [HR 2.01 (95% CI 1.40-2.61)] and with VKA [HR 1.95 (95% CI 1.21-2.69)]., Conclusion: Among this nationwide AF population taking OACs, concomitant NSAID therapy increased the short-term absolute risk of GIB. Non-vitamin K antagonist oral anticoagulants alone were associated with lower GIB risks than VKA but concomitant NSAIDs abolished this advantage. The findings align with post hoc analyses from randomized studies. Physicians should exercise appropriate caution when prescribing NSAIDs for patients with AF taking NOACs or VKA., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Aims: The aim of this study was to describe the use of antithrombotic therapy following a bleeding event among patients with myocardial infarction (MI), and the associated risk of major adverse cardiac events (MACE)., Methods and Results: Using Danish nationwide registries, patients hospitalized with a bleeding event within 1 year after MI were identified. Antithrombotic treatment with aspirin, clopidogrel, and/or vitamin K antagonists (VKA) was determined at the bleeding and at Day 90 and 180 post-bleed. Based on guidelines, patients were stratified into four groups: expected, reduced, discontinued, or intensified treatment. Risk of MACE (ischaemic stroke, MI, or death) within the first year was assessed by Cox proportional hazard models. A total of 3324 patients with a bleeding after MI were included. At Day 90 post-bleed, 1052 (31.7%) received expected antithrombotic treatment, 1301 (39.2%) reduced, 164 (4.9%) intensified, and 807 (24.3%) no treatment. Major adverse cardiac events occurred in 637 (19.2%) patients. With dual antiplatelet therapy as reference, adjusted hazard ratios for MACE were: aspirin 1.81 (1.06-3.09), clopidogrel 1.08 (0.64-1.82), VKA 1.08 (0.47-2.48), VKA + aspirin 1.97 (0.95-4.07), VKA + clopidogrel 0.26 (0.03-1.91), triple 1.73 (0.50-5.95), and no treatment 1.93 (1.11-3.36)., Conclusion: The majority of MI patients reduced or discontinued their antithrombotic therapy post-bleed. Patients in monotherapy with aspirin or no treatment post-bleed had a higher risk of MACE Further studies of optimal antithrombotic treatments after a bleed are needed., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Background: The purpose of the study was to examine the association between the type of preceding oral anticoagulant use (warfarin or direct oral anticoagulants [DOACs]) and in-hospital mortality among patients admitted with gastrointestinal bleeding., Methods: In this observational cohort study, all patients admitted with a first-time gastrointestinal bleeding from January 2011 to March 2017 while receiving any oral anticoagulant therapy prior to admission were identified using data from Danish nationwide registries. The risk of in-hospital mortality according to type of oral anticoagulation therapy was examined by multivariable logistic regression models., Results: Among 5,774 patients admitted with gastrointestinal bleeding (median age, 78 years [25th-75th percentile, 71-85 years]; 56.8% men), 2,038 (35.3%) were receiving DOACs and 3,736 (64.7%) were receiving warfarin prior to admission. The unadjusted in-hospital mortality rates were 7.5% for DOAC (7.2% for dabigatran, 6.4% for rivaroxaban, and 10.1% for apixaban) and 6.5% for warfarin. After adjustment for baseline demographic and clinical characteristics, there was no statistically significant difference in in-hospital mortality between prior use of any DOAC and warfarin (unadjusted odds ratio [OR] 1.18 [95% CI 0.95-1.45], adjusted OR 0.97 [95% CI 0.77-1.24]). Similar results were found for each individual DOAC as compared with warfarin (dabigatran: unadjusted OR 1.12 [95% CI 0.84-1.49], adjusted OR 0.96 [95% CI 0.71-1.30]); rivaroxaban: unadjusted OR 0.98 [95% CI 0.71-1.37], adjusted OR 0.84 [95% CI 0.59-1.21]; and apixaban: unadjusted OR 1.62 [95% CI 0.84-1.49], adjusted OR 1.22 [95% CI 0.83-1.79])., Conclusions: Among patients admitted with gastrointestinal bleeding, there was no statistically significant difference in in-hospital mortality between prior use of DOAC and warfarin., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Aims: Patients with non-valvular atrial fibrillation (NVAF) receiving vitamin K antagonists (VKAs) with time in therapeutic international normalized ratio (INR) range (TTR) <70%, despite good adherence, are by guidelines recommended to switch to non-VKA oral anticoagulants (NOACs). The aim was to assess if patients are switched from VKA to NOAC when TTR is <70% in a real-world setting., Methods and Results: Non-valvular atrial fibrillation patients receiving VKA (1 January 2010 to 31 December 2012) were identified in nationwide registries. Time in therapeutic range was calculated by the Rosendaal method by a minimum of three INR values. Time in therapeutic range of patients continuing VKA (non-switchers) were compared with patients switched from VKA to dabigatran or rivaroxaban (switchers), the only NOACs available at that time. Factors associated with switching were analysed in a multivariable logistic regression model. 7276 patients with NVAF receiving VKA were included; of these, 6437 (88.5%) patients continued VKA [57.9% male, median age 76.7 years (Q1-Q3 68.9-83.5)] and 839 (11.5%) switched to NOAC [54.0% male, median age 76.5 years (Q1-Q3 68.4-83.6)]. No significant differences in CHA2DS2-VASc and HAS-BLED scores were seen between the groups. The mean TTR for non-switchers was 64.0 [standard deviation (SD) 27.8] and 52.9 (SD 28.1) for switchers. Among non-switchers, 51% had a TTR <70% vs. 69% among switchers. 85% of patients with TTR <70%, were not switched contrary to recommendations. Time in therapeutic range <70% was associated with the switch [odds ratio 2.28, 95% confidence interval (1.92-2.72)]., Conclusion: A TTR below 70% was associated with switching from VKA to NOAC, yet by guidelines, most patients were still not switched., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. For permissions, please email: journals.permissions@oup.com.)

Background: The long-term risk of thromboembolism in patients developing new-onset post-operative atrial fibrillation (POAF) following noncardiac surgery is unknown, and data on stroke prophylaxis in this setting are lacking., Objectives: The purpose of this study was to assess the long-term risk of thromboembolism in patients developing new-onset POAF following noncardiac surgery relative to patients with nonsurgical, nonvalvular atrial fibrillation (NVAF)., Methods: Using Danish nationwide registries, the authors identified all patients who developed POAF following noncardiac surgery from 1996 to 2015. These were matched by age, sex, heart failure, hypertension, diabetes, previous thromboembolism, ischemic heart disease, and year of diagnosis to patients with nonsurgical NVAF in a 1:4 ratio. Comparative long-term risk of thromboembolism was examined by multivariable Cox regression models., Results: In patients undergoing noncardiac surgery, 6,048 (0.4%) developed POAF during hospitalization, with the highest incidences following thoracic/pulmonary, vascular, and abdominal surgery. A total of 3,830 patients with POAF were matched with 15,320 patients with NVAF. Oral anticoagulation therapy was initiated within 30 days post-discharge in 24.3% and 41.3% of these patients, respectively (p value <0.001). The long-term risk of thromboembolism was similar in patients with POAF and NVAF (31.7 events vs. 29.9 events per 1,000 person years; hazard ratio [HR]: 0.95; 95% confidence interval [CI]: 0.85 to 1.07). Anticoagulation therapy during follow-up was associated with a comparably lowered risk of thromboembolic events in patients with POAF (HR: 0.52; 95% CI: 0.40 to 0.67) as well as NVAF (HR: 0.56; 95% CI: 0.51 to 0.62) compared with no anticoagulation therapy., Conclusions: New-onset POAF following noncardiac surgery was associated with a long-term risk of thromboembolism similar to NVAF., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Aims: After non-vitamin K antagonist (VKA) oral anticoagulation agents (NOAC) have been approved for thrombo-embolic prophylaxis in non-valvular atrial fibrillation (NVAF), utilization of oral anticoagulants (OAC) in NVAF has changed. Contemporary shifting from a VKA to a NOAC (dabigatran, rivaroxaban, or apixaban) has not been quantified, and could help assess whether these drugs are used according to recommendations., Methods and Results: Using Danish nationwide registries, we identified all VKA-experienced NVAF patients initiating a NOAC from 22 August 2011 to 31 December 2015 (shifters) and all VKA-experienced NVAF patients who were not switched to NOACs (non-shifters). Baseline characteristics and temporal utilization trends were examined. We included 62 065 patients with NVAF; of these, 19 386 (29.6%) shifted from a VKA to a NOAC (9973 (54.2%) shifted to dabigatran, 4775 (26.0%) to rivaroxaban, and 3638 (19.8%) to apixaban). Shifting was associated with lower age [odds ratio (OR) 0.95, 95% confidence interval (95% CI) 0.94-0.96 per 5 year increments], female gender (OR 1.33, 95% CI 1.28-1.38), and certain co-morbidities: more often stroke, bleeding, heart failure, and alcohol abuse, and less often hypertension, ischaemic heart disease, and diabetes. Shifting was common and initially dominated by shifting from VKA to dabigatran, but at the end of 2015, most shifters were shifted to rivaroxaban (45%) or apixaban (45%) whereas shifting to dabigatran decreased (to 10%)., Conclusion: In a contemporary setting among VKA-experienced NVAF patients; VKA is still prevalent although about 30% by December 2015 had shifted to a NOAC.

Aims: We examined the risks of all-cause mortality, stroke, major bleeding, and recurrent traumatic injury associated with resumption of vitamin K antagonists (VKAs) and non-VKAs oral anticoagulants (NOACs) following traumatic injury in atrial fibrillation (AF) patients., Methods and Results: This was a Danish nationwide registry-based study (2005-16), including 4541 oral anticoagulant (OAC)-treated AF patients experiencing traumatic injury (defined as traumatic brain injury, hip fracture, or traumatic torso or abdominal injury). Within 90 days following discharge from traumatic injury, 60.6% resumed VKA (median age = 80, CHA2DS2-VASc = 4, HAS-BLED = 2), 16.7% resumed NOAC (median age = 81, CHA2DS2-VASc = 4, HAS-BLED = 2), and 22.7% did not resume OAC treatment (median age = 81, CHA2DS2-VASc = 4, HAS-BLED = 3). Switch from VKA to NOAC occurred among 9.5%. Since 2009, the trend in OAC resumption increased (P-value <0.0001), in particular with NOACs (P-value <0.0001). Follow-up started 90 days after discharge, and time-varying multiple Cox regression analyses were used for comparisons. Compared with non-resumption, VKA and NOAC resumption were associated with lower hazard [95% confidence interval (CI)] of all-cause mortality [hazard ratio (HR) 0.48 (0.42-0.53) and HR 0.55 (0.47-0.66), respectively] and ischaemic stroke [HR 0.56 (0.43-0.72) and HR 0.54 (0.35-0.82), respectively], increased major bleeding hazard [HR 1.30 (1.03-1.64) and HR 1.15 (0.81-1.63), respectively], and similar hazard of recurrent traumatic injury [HR 0.93 (0.73-1.18) and HR 0.87 (0.60-1.27), respectively]., Conclusion: AF patients resuming VKA and NOAC treatment following traumatic injury have lower hazard of all-cause mortality and ischaemic stroke, increased hazard of major bleeding but without additional hazards of recurrent traumatic injury. Withholding OAC following a traumatic injury in AF patients may not be warranted.

Introduction, Materials and Methods: We used Danish nationwide registries to examine temporal trends in the predicted stroke and bleeding risks (mean CHA 2 DS 2 -VASc and HAS-BLED scores per year, respectively) as well as the combination of selected stroke and bleeding risk factors per year among atrial fibrillation (AF) patients initiated for the first time between 2011 and 2016 on vitamin K antagonists (VKAs), dabigatran, rivaroxaban, or apixaban., Results: In total, 53,860 AF patients were included (VKA 37.7%, dabigatran 24.4%, rivaroxaban 16.9%, apixaban 21.0%). For standard dose dabigatran initiators, during almost all of the study period, the mean CHA 2 DS 2 -VASc and HAS-BLED scores were the lowest and decreased (2.6 and 2.2 in 2011 vs. 2.1 and 1.8 in 2016, respectively). Reduced dose apixaban initiators had rather stable mean CHA 2 DS 2 -VASc scores during the study period and the highest mean CHA 2 DS 2 -VASc score in 2016 (4.1). The mean HAS-BLED scores were similarly high among reduced dose apixaban and rivaroxaban initiators in years 2013-2016. From 2011 to 2014, a decrease in the frequency of prior stroke (p<0.001), age≥75years (p<0.001), and prior bleeding (p=0.007) was observed among dabigatran initiators. In the study period, apixaban initiators in general had the highest frequency of prior stroke and age≥75years., Conclusions: Danish AF patients receiving standard dose dabigatran had the lowest and decreasing predicted stroke and bleeding risks during almost all study years. Patients receiving reduced dose apixaban had rather stable predicted risk of stroke during the study period and the highest mean CHA 2 DS 2 -VASc score in 2016., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: The use of non-vitamin K antagonist oral anticoagulants (NOACs) for stroke prophylaxis in atrial fibrillation (AF) is increasing rapidly. We compared characteristics of AF patients initiated on NOACs versus vitamin K antagonists (VKAs)., Methods: Using Danish nationwide registry data, we identified AF patients initiating either a VKA or a NOAC from 22 August 2011 until 30 September 2016. We compared patient characteristics including age, gender, comorbidities, concomitant pharmacotherapy and CHA 2 DS 2 -VASc and HAS-BLED scores in patients initiated on a VKA, dabigatran, rivaroxaban or apixaban. Differences were examined using multivariable logistic regression models., Results: The study population comprised 51 981 AF patients of whom 19 989 (38.5%) were initiated on a VKA, 13 242 (25.5%) on dabigatran, 8475 (16.3%) on rivaroxaban and 10 275 (19.8%) on apixaban. Those patients initiated on apixaban had higher mean ± SD CHA 2 DS 2 -VASc scores than those initiated on a VKA (3.1 ± 1.6 vs. 2.9 ± 1.6). Those initiated on dabigatran had lower mean CHA 2 DS 2 -VASc scores (2.7 ± 1.6) than all other groups. Patients with a history of a prior stroke were significantly more likely to be initiated on a NOAC compared with a VKA [odds ratio (OR) 1.35, 95% confidence interval (CI) 1.28-1.43]. By contrast, patients with a history of myocardial infarction were less likely to be initiated on a NOAC compared with a VKA (OR 0.72, 95% CI 0.67-0.77)., Conclusions: Atrial fibrillation patients who were initiated on apixaban had higher stroke risk scores than patients initiated on VKAs. Interestingly, opposite results were found for dabigatran., (© 2017 The Association for the Publication of the Journal of Internal Medicine.)

The approval of rivaroxaban has changed the landscape of treatment of venous thromboembolism (VTE). Little is known about the effect of rivaroxaban compared with vitamin K antagonists (VKA), when used in the everyday clinical practice. The aim of this study was to investigate the safety and effectiveness of rivaroxaban compared with VKAs among patients with VTE, using the Danish nationwide registries. All patients diagnosed with VTE and treated with either rivaroxaban or VKAs between 2013 and 2015 were included. A total of 12,318 patients were diagnosed with VTE and treated with VKAs [n=6,907] or rivaroxaban [n=5,411.]. Combined Cox regression analyses showed that the standardised absolute six-month risk of recurrent VTE was 3.03 % [95 % CI: 2.57 % to 3.48 %] in the rivaroxaban group and 3.13 % [95 % CI: 2.70 % to 3.56 %] in the VKA group (absolute risk difference of -0.11 % [95 % CI: -0.76 % to 0.54 %]). The standardised absolute six-months risk of bleeding was 2.28 % [95 % CI: 1.87 % to 2.67 %] for patients in the rivaroxaban group and 2.10 % [95 % CI: 1.78 % to 2.43 %] in the VKA group (absolute risk difference of 0.18 % [95 % CI: -0.34 % to 0.67]). In conclusion, rivaroxaban was associated with similar risk of recurrent VTE and bleeding compared with VKA.

Background: Non-vitamin K antagonist (VKA) oral anticoagulants (NOACs) are widely used as stroke prophylaxis in non-valvular atrial fibrillation (AF), but comparative data are sparse., Purpose: To compare dabigatran, rivaroxaban, and apixaban vs. VKA and the risk of stroke/thromboembolism (TE) and intracranial bleeding in AF., Methods: Using Danish nationwide registries (2011-15), anticoagulant-naïve AF patients were identified when initiating VKA or an NOAC. Outcomes were stroke/TE and intracranial bleeding. Multiple outcome-specific Cox regression was performed to calculate average treatment effects as standardized differences in 1-year absolute risks., Results: Overall, 43 299 AF patients initiated VKA (42%), dabigatran (29%), rivaroxaban (13%), and apixaban (16%). Mean CHA2DS2-VASc (SD) score was: VKA 2.9 (1.6), dabigatran 2.7 (1.6), rivaroxaban 3.0 (1.6), and apixaban 3.1 (1.6). Within patient-specific follow-up limited to the first 2 years, 1054 stroke/TE occurred and 261 intracranial bleedings. Standardized absolute risk (95% CI) of stroke/TE at 1 year after initiation of VKA was 2.01% (1.80% to 2.21%). In relation to VKA, the absolute risk differences were for dabigatran 0.11% (-0.16% to 0.42%), rivaroxaban 0.05% (-0.33% to 0.48%), and apixaban 0.45% (-0.001% to 0.93%). For the intracranial bleeding outcome, the standardized absolute risk at 1 year was for VKA 0.60% (0.49% to 0.72%); the corresponding absolute risk differences were for dabigatran -0.34% (-0.47% to - 0.21%), rivaroxaban -0.13% (-0.33% to 0.08%), and apixaban -0.20% (-0.38% to - 0.01%)., Conclusions: Among anticoagulant-naïve AF patients, treatment with NOACs was not associated with significantly lower risk of stroke/TE compared with VKA, but intracranial bleeding risk was significantly lower with dabigatran and apixaban., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For Permissions, please email: journals.permissions@oup.com.)

Aim: The aim of this study is to examine temporal trends in the use oral anticoagulants (OAC) as stroke prophylaxis in patients with atrial fibrillation (AF) and to examine factors associated with OAC initiation., Methods and Results: From Danish nationwide registries, we identified patients diagnosed with AF at Danish hospitals and outpatient clinics between January 2005 and June 2015. OAC initiation was assessed from prescription fills ±180 days from date of AF diagnosis. We identified a total of 108 410 patients with newly diagnosed AF. Before 2010, 40-50% initiated OAC treatment. From 2010, OAC initiation rates increased (P < 0.0001 for trend) and by June 2015, 66.5% of the incident AF patients were initiated on OAC (74.5% increase since December 2009). Increased OAC prescription was especially seen among females and 'fragile' patients (age > 75 years and high risk of stroke). The increased OAC initiation was accompanied by introduction and increased uptake of the NOACs. By the end of the study, NOACs accounted for 72.5% of all OACs prescribed in newly diagnosed AF patients. OAC initiation was associated with male gender, age 65-74 years, few comorbidities and increased risk of stroke., Conclusion: Since 2010, more incident AF patients in Denmark were initiated on OAC therapy with predominant NOAC prescription. The increase was pronounced among females, among patients at high risk of stroke, and among older patients., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.)

Background: The nonvitamin K antagonist oral anticoagulants have recently become available as an alternative to warfarin as stroke prophylaxis in atrial fibrillation, but data on real-life patient experience, including bleeding risk, are lacking. Our objective was to compare major bleeding events and nonpersistence between the nonvitamin K antagonist oral anticoagulant apixaban and other nonvitamin K antagonist oral anticoagulants (dabigatran and rivaroxaban) and warfarin in a contemporary, nation-wide cohort of patients with nonvalvular atrial fibrillation., Methods and Results: Of 54 321 patients (median age, 73 years; 56% male; mean CHA 2 DS 2 -VASc score, 2.9), 7963, 6715, 15 413, and 24 230 patients initiated apixaban, rivaroxaban, dabigatran, and warfarin, respectively. Apixaban and rivaroxaban initiators were older, less often male, with higher HAS-BLED and CHA 2 DS 2 -VASc scores compared with dabigatran and warfarin initiators. A total of 2418 patients (4.5%) experienced a major bleeding event over all available follow-up. In this period, rivaroxaban (hazard ratio [HR] [95% CI], 1.49 [1.27-1.77]), dabigatran (HR, 1.17 [1.00-1.38]), and warfarin (HR, 1.23 [1.05-1.43]) users were significantly more likely to bleed than apixaban users. Findings were similar when restricted to the first 30 days after OAC initiation. Risk of nonpersistence was higher for dabigatran (HR, 1.45 [1.33-1.59]) and warfarin initiators (HR, 1.22 [1.12-1.33]), but not for rivaroxaban initiators (HR, 1.07 [0.96-1.20]) compared with apixaban initiators., Conclusions: In a real-world cohort of nonvalvular atrial fibrillation patients, apixaban had a lower adjusted major bleeding risk compared with rivaroxaban, dabigatran, and warfarin. Apixaban had a lower risk of nonpersistence compared with dabigatran and warfarin and similar risk compared with rivaroxaban., (© 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

Background and Purpose: We sought to determine the risk of stroke/thromboembolism and bleeding associated with reduced renal function in patients with atrial fibrillation and the risk of stroke and bleeding associated with warfarin treatment in specific estimated glomerular filtration rate (eGFR) groups., Methods: We conducted a register-based cohort study and included patients discharged with nonvalvular atrial fibrillation from 1997 to 2011 with available eGFR., Results: A total of 17 349 patients were identified with eGFR available at baseline. All levels of lower eGFR were associated with higher risk of stroke/thromboembolism and bleeding. Use of warfarin was associated with higher bleeding risk in all eGFR groups; hazard ratios 1.23 (95% confidence interval [CI], 0.97-1.56), 1.26 (95% CI, 1.14-1.40), 1.18 (95% CI, 1.07-1.31), 1.11 (95% CI, 0.87-1.42), 2.01 (95% CI, 1.14-3.54) in patients with eGFR ≥90, 60 to 89, 30 to 59, 15 to 29, and <15 mL/min per 1.73 m 2 , respectively. Use of warfarin was associated with lower risk of stroke/thromboembolism in patients with eGFR ≥15 mL/min per 1.73 m 2 ; hazard ratios 0.57 (95% CI, 0.43-0.76), 0.57 (95% CI, 0.51-0.64), 0.48 (95% CI, 0.44-0.54), 0.60 (95% CI, 0.45-0.80) in patients with eGFR ≥90, 60 to 89, 30 to 59, and 15 to 29 mL/min per 1.73 m 2 , respectively. Use of warfarin was not associated with lower risk of stroke/thromboembolism in patients with eGFR<15 mL/min per 1.73 m 2 ; hazard ratio 1.18 (95% CI, 0.58-2.40)., Conclusions: In patients with atrial fibrillation, the risk of stroke and bleeding was associated with levels of renal function. Warfarin treatment was associated with higher risk of bleeding in all eGFR groups and lower risk of stroke in patients with eGFR≥15 mL/min per 1.73 m 2 ., (© 2016 American Heart Association, Inc.)

Background: Knowledge about drug-drug interactions commonly arises from preclinical trials, from adverse drug reports, or based on knowledge of mechanisms of action. Our aim was to investigate whether drug-drug interactions were discoverable without prior hypotheses using data mining. We focused on warfarin-drug interactions as the prototype., Methods and Results: We analyzed altered prothrombin time (measured as international normalized ratio [INR]) after initiation of a novel prescription in previously INR-stable warfarin-treated patients with nonvalvular atrial fibrillation. Data sets were retrieved from clinical work. Random forest (a machine-learning method) was set up to predict altered INR levels after novel prescriptions. The most important drug groups from the analysis were further investigated using logistic regression in a new data set. Two hundred and twenty drug groups were analyzed in 61 190 novel prescriptions. We rediscovered 2 drug groups having known interactions (β-lactamase-resistant penicillins [dicloxacillin] and carboxamide derivatives) and 3 antithrombotic/anticoagulant agents (platelet aggregation inhibitors excluding heparin, direct thrombin inhibitors [dabigatran etexilate], and heparins) causing decreasing INR. Six drug groups with known interactions were rediscovered causing increasing INR (antiarrhythmics class III [amiodarone], other opioids [tramadol], glucocorticoids, triazole derivatives, and combinations of penicillins, including β-lactamase inhibitors) and two had a known interaction in a closely related drug group (oripavine derivatives [buprenorphine] and natural opium alkaloids). Antipropulsives had an unknown signal of increasing INR., Conclusions: We were able to identify known warfarin-drug interactions without a prior hypothesis using clinical registries. Additionally, we discovered a few potentially novel interactions. This opens up for the use of data mining to discover unknown drug-drug interactions in cardiovascular medicine., (© 2016 American Heart Association, Inc.)

Aims: Non-vitamin K antagonist oral anticoagulation (NOAC) agents have been approved for stroke prophylaxis in atrial fibrillation (AF). We investigated 'real-world' information on how these drugs are being adopted., Methods and Results: Using Danish nationwide administrative registers, we identified all oral anticoagulation-naïve AF patients initiating oral anticoagulation from 22 August 2011 through 31 October 2013. Using logistic regression analysis, baseline characteristics and temporal utilization trends were compared between initiators of warfarin vs. one of the N OACs: dabigatran, rivaroxaban, or apixaban. We identified 18 611 oral anticoagulation-naïve AF patients of which 9902 (53%) initiated warfarin treatment, 7128 (38%) dabigatran, 1303 (7%) rivaroxaban, and 278 (1%) apixaban. Overall, 40% of newly initiated patients were started on dabigatran within the first 4 months of when the drug came on market. By October, 2013, 40% were being started on warfarin and dabigatran, respectively, and another 20% were started on either rivaroxaban or apixaban. Rivaroxaban and apixaban users generally had a higher predicted risk of stroke and bleeding compared with warfarin and dabigatran users. Older age, female gender, and prior stroke were some of the factors associated with NOAC use vs. warfarin, whereas chronic kidney disease, myocardial infarction, and heart failure showed the opposite association., Conclusion: Among oral anticoagulation-naïve AF patients initiated on oral anticoagulation in Denmark, warfarin initiation has declined since the introduction of dabigatran in August 2011. Dabigatran is the most frequently used alternative option to warfarin; however, use of rivaroxaban and apixaban is increasing. Patients initiated with rivaroxaban or apixaban in general have a higher predicted stroke and bleeding risks compared with warfarin or dabigatran initiators., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.)

Objective: To analyse how hospital factors influence the use of oral anticoagulants (OAC) in atrial fibrillation (AF) patients and address the clinical consequences of hospital variation in OAC use., Design and Subjects: By linkage of nationwide Danish administrative registers we conducted an observational study including all patients with a first-time hospitalization for AF between 1995 and 2004 as well as prescription claims for OAC. Multivariable logistic regression analysis was used to evaluate hospital factors associated with prescription of OAC therapy. Cox proportional-hazard models were used to estimate the risk of re-hospitalization for thromboembolism and haemorrhagic stroke with respect to discharge from a low, intermediate, or high OAC use hospital., Results: Overall 40,133 (37%) out of 108,504 patients received OAC; ranging from 17% to 50% between the hospitals with the lowest and highest OAC use, respectively. Cardiology departments had the highest use of OAC, but neither tertiary university hospitals nor high volume hospitals had higher OAC use than local community hospitals and low volume hospitals. Risk of a thromboembolic event was significantly increased amongst patients from hospitals with a low OAC use (hazard ratio 1.16, confidence interval 1.10-1.22). Notably, higher OAC use was not associated with a higher risk of haemorrhagic stroke., Conclusion: In Denmark between 1995 and 2004, there was a major hospital variation in AF patients receiving OAC, and consequently, more thromboembolic events were observed amongst patients from low OAC use hospitals. Our study emphasizes the need for a continued vigilance on implementation of international AF management guidelines.