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Safety and Efficacy of Vitamin K Antagonists versus Rivaroxaban in Hemodialysis Patients with Atrial Fibrillation: A Multicenter Randomized Controlled Trial.
De Vriese, AS, Caluwé, R, Van Der Meersch, H, De Boeck, K, De Bacquer, D
Journal of the American Society of Nephrology : JASN. 2021;(6):1474-1483
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Abstract
BACKGROUND In patients with normal renal function or early stage CKD, the risk-benefit profile of direct oral anticoagulants (DOACs) is superior to that of vitamin K antagonists (VKAs). In patients on hemodialysis, the comparative efficacy and safety of DOACs versus VKAs are unknown. METHODS In the Valkyrie study, 132 patients on hemodialysis with atrial fibrillation were randomized to a VKA with a target INR of 2-3, 10 mg rivaroxaban daily, or rivaroxaban and vitamin K2 for 18 months. Patients continued the originally assigned treatment and follow-up was extended for at least an additional 18 months. The primary efficacy end point was a composite of fatal and nonfatal cardiovascular events. Secondary efficacy end points were individual components of the composite outcome and all-cause death. Safety end points were life-threatening, major, and minor bleeding. RESULTS Median (IQR) follow-up was 1.88 (1.01-3.38) years. Premature, permanent discontinuation of anticoagulation occurred in 25% of patients. The primary end point occurred at a rate of 63.8 per 100 person-years in the VKA group, 26.2 per 100 person-years in the rivaroxaban group, and 21.4 per 100 person-years in the rivaroxaban and vitamin K2 group. The estimated competing risk-adjusted hazard ratio for the primary end point was 0.41 (95% CI, 0.25 to 0.68; P=0.0006) in the rivaroxaban group and 0.34 (95% CI, 0.19 to 0.61; P=0.0003) in the rivaroxaban and vitamin K2 group, compared with the VKA group. Death from any cause, cardiac death, and risk of stroke were not different between the treatment arms, but symptomatic limb ischemia occurred significantly less frequently with rivaroxaban than with VKA. After adjustment for competing risk of death, the hazard ratio for life-threatening and major bleeding compared with the VKA group was 0.39 (95% CI, 0.17 to 0.90; P=0.03) in the rivaroxaban group, 0.48 (95% CI, 0.22 to 1.08; P=0.08) in the rivaroxaban and vitamin K2 group and 0.44 (95% CI, 0.23 to 0.85; P=0.02) in the pooled rivaroxaban groups. CONCLUSIONS In patients on hemodialysis with atrial fibrillation, a reduced dose of rivaroxaban significantly decreased the composite outcome of fatal and nonfatal cardiovascular events and major bleeding complications compared with VKA. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER Oral Anticoagulation in Hemodialysis, NCT03799822.
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Details on the effect of very short dual antiplatelet therapy after drug-eluting stent implantation in patients with high bleeding risk: insight from the STOPDAPT-2 trial.
Watanabe, H, Domei, T, Morimoto, T, Natsuaki, M, Shiomi, H, Toyota, T, Ohya, M, Suwa, S, Takagi, K, Nanasato, M, et al
Cardiovascular intervention and therapeutics. 2021;(1):91-103
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Previously we briefly reported the effect of 1-month dual antiplatelet therapy (DAPT) for patients with high bleeding risk (HBR) receiving percutaneous coronary intervention (PCI) in the STOPDAPT-2 trial, but full analysis data have not been available. We conducted post hoc subgroup analysis regarding the effect of very short DAPT for HBR patients in STOPDAPT-2 trial. The primary endpoint was a 1-year composite of cardiovascular (cardiovascular death, myocardial infarction, definite stent thrombosis, or stroke) and bleeding (TIMI major/minor bleeding) outcomes. Major secondary endpoints were 1-year cardiovascular composite endpoint and bleeding endpoint. HBR was defined by the academic research consortium (ARC) HBR criteria. Among the 3009 study patients, 1054 (35.0%) were classified as HBR and 1955 (65.0%) were as non-HBR. There were no significant interactions between HBR/non-HBR subgroups and the assigned DAPT group on the primary endpoint (HBR; 3.48% vs. 5.98%, HR 0.57, 95% CI 0.32-1.03, and non-HBR; 1.81% vs. 2.36%, HR 0.78, 95% CI 0.42-1.45; P for interaction = 0.48), the major secondary cardiovascular endpoint (HBR; 3.07% vs. 4.03%, HR 0.77, 95% CI 0.40-1.48, and non-HBR; 1.41% vs. 1.61%, HR 0.89, 95% CI 0.43-1.84; P for interaction = 0.77), and the major secondary bleeding endpoint (HBR; 0.41% vs. 2.71%, HR 0.15, 95% CI 0.03-0.65, and non-HBR; 0.40% vs. 0.85%, HR 0.48, 95% CI 0.14-1.58; P for interaction = 0.22). In conclusion, the effects of 1-month DAPT for the primary and major secondary endpoints were consistent in HBR and non-HBR patients without any significant interactions. The benefit of 1-month DAPT in reducing major bleeding was numerically greater in HBR patients.Clinical trial registration Short and optimal duration of dual antiplatelet therapy after everolimus-eluting cobalt-chromium stent-2 [STOPDAPT-2]; NCT02619760.
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Severe Hemorrhage Associated With Oral Anticoagulants.
Lindhoff-Last, E, Herrmann, E, Lindau, S, Konstantinides, S, Grottke, O, Nowak-Goettl, U, Lucks, J, Zydek, B, Heymann, CV, Birschmann, I, et al
Deutsches Arzteblatt international. 2020;(18):312-319
Abstract
BACKGROUND Few data have been published to date on outcomes after the common clinical experience of severe hemorrhage in orally anticoagulated patients. METHODS A prospective, multicenter observational study was carried out to investigate outcomes and management in a series of consecutive patients who sustained a severe hemorrhage under treatment with vitamin K antagonists (VKA) or direct oral anticoagulant drugs (DOAC). The primary endpoint was in-hospital death up to and including day 30 after hospital admission. The secondary endpoints were the duration of bleeding, in-hospital death due to hemorrhage (as defined by the study physician examining the patient's records), the use of antagonists, the extent of supportive measures used to stop the hemorrhage, and an assessment of causality. Consecutive patients were recruited until a predefined number of patients was reached in both groups. RESULTS Among 193 patients with severe hemorrhage, 97 had been taking a VKA, and 96 had been taking a DOAC. 13.0 % (95% confidence interval [8.6; 18.5]; 25/193) of the overall group patients died in the first 30 days after hospital admission, including 17.5% ([10.6; 26.6]; 17/97) in the VKA group and 8.3% ([3.7; 15.8]; 8/96) in the DOAC group (p = 0.085). The median duration of bleeding was 19.8 hours in the VKA group and 27.8 hours in the DOAC group (p = 0.632). The in-hospital mortality due to hemorrhage was higher in the VKA group than in the DOAC group (15.5% [15/97] versus 4.2% [4/97]; p = 0.014). Only the use of prothrombin complex concentrates (PCCs) lowered the median duration of hemorrhage in the two patient groups. In 35% (68/193) of the patients, the hemorrhage was caused by an external influence, most commonly a fall. CONCLUSION The in-hospital mortality was higher among patients treated with VKA than among patients treated with DOAC, although the difference failed to reach statistical significance.
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Management of therapeutic anticoagulation in patients with intracerebral haemorrhage and mechanical heart valves.
Kuramatsu, JB, Sembill, JA, Gerner, ST, Sprügel, MI, Hagen, M, Roeder, SS, Endres, M, Haeusler, KG, Sobesky, J, Schurig, J, et al
European heart journal. 2018;(19):1709-1723
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AIMS: Evidence is lacking regarding acute anticoagulation management in patients after intracerebral haemorrhage (ICH) with implanted mechanical heart valves (MHVs). Our objective was to investigate anticoagulation reversal and resumption strategies by evaluating incidences of haemorrhagic and thromboembolic complications, thereby defining an optimal time-window when to restart therapeutic anticoagulation (TA) in patients with MHV and ICH. METHODS AND RESULTS We pooled individual patient-data (n = 2504) from a nationwide multicentre cohort-study (RETRACE, conducted at 22 German centres) and eventually identified MHV-patients (n = 137) with anticoagulation-associated ICH for outcome analyses. The primary outcome consisted of major haemorrhagic complications analysed during hospital stay according to treatment exposure (restarted TA vs. no-TA). Secondary outcomes comprised thromboembolic complications, the composite outcome (haemorrhagic and thromboembolic complications), timing of TA, and mortality. Adjusted analyses involved propensity-score matching and multivariable cox-regressions to identify optimal timing of TA. In 66/137 (48%) of patients TA was restarted, being associated with increased haemorrhagic (TA = 17/66 (26%) vs. no-TA = 4/71 (6%); P < 0.01) and a trend to decreased thromboembolic complications (TA = 1/66 (2%) vs. no-TA = 7/71 (10%); P = 0.06). Controlling treatment crossovers provided an incidence rate-ratio [hazard ratio (HR) 10.31, 95% confidence interval (CI) 3.67-35.70; P < 0.01] in disadvantage of TA for haemorrhagic complications. Analyses of TA-timing displayed significant harm until Day 13 after ICH (HR 7.06, 95% CI 2.33-21.37; P < 0.01). The hazard for the composite-balancing both complications, was increased for restarted TA until Day 6 (HR 2.51, 95% CI 1.10-5.70; P = 0.03). CONCLUSION Restarting TA within less than 2 weeks after ICH in patients with MHV was associated with increased haemorrhagic complications. Optimal weighing-between least risks for thromboembolic and haemorrhagic complications-provided an earliest starting point of TA at Day 6, reserved only for patients at high thromboembolic risk.
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The American College of Chest Physician score to assess the risk of bleeding during anticoagulation in patients with venous thromboembolism.
Palareti, G, Antonucci, E, Mastroiacovo, D, Ageno, W, Pengo, V, Poli, D, Testa, S, Tosetto, A, Prandoni, P
Journal of thrombosis and haemostasis : JTH. 2018;(10):1994-2002
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UNLABELLED Essentials The risk of bleeding influences the duration of anticoagulation (AC) after venous thromboembolism. We assessed the ACCP bleeding risk score in an inception-cohort of patients receiving AC. 53% were categorized at high-risk, but their bleeding rate was low during long-term AC. ACCP score had low predictive value for bleeding. SUMMARY Background The American College of Chest Physicians (ACCP) guideline proposes a score to decide on extended anticoagulation after an unprovoked venous thromboembolism (VTE). Methods We investigated the ACCP score to predict bleeding risk in an inception cohort of 2263 patients on long-term anticoagulation (1522 treated with vitamin K antagonists [VKAs] and the remaining with direct oral anticoagulants [DOACs]) belonging to the Italian START2 Register. Results More than half the patients were categorized as high risk; nevertheless, a higher proportion received anticoagulation for > 1 year compared with those in the low-risk category. For 3130 years (median 12 [interquartile range 6, 24] months), 48 bleeding outcomes occurred (1.53%/year) in the cohort (1.7%/year and 0.95%/year in high- and low-risk categories, respectively). The c-statistic of the ACCP score was 0.55 (0.48-0.63), 0.50 (0.42-0.58) and 0.56 (0.48-0.64) in low-, moderate- and high-risk categories, respectively. The bleeding incidence was higher during the first 90 days of treatment (3.0%/year) than afterwards (1.2%/year; relative risk (RR), 2.5 [1.3-4.7]), and similar among the three categories. The bleeding rate was not different during the initial 3 months of treatment in patients receiving VKAs or DOACs; it was, however, lower in the latter patients in the subsequent period (0.5%/year vs. 1.4%/year, respectively). Conclusion The bleeding rate during extended treatment was rather low in our patients. ACCP score had insufficiently predictive value for bleeding and cannot be used to guide decisions on extended treatment. New prediction tools for bleeding risk during anticoagulant treatments (including DOACs) are required.
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Comparison of clinical characteristics of real-life atrial fibrillation patients treated with vitamin K antagonists, dabigatran, and rivaroxaban: results from the CRAFT study.
Balsam, P, Ozierański, K, Tymińska, A, Żukowska, K, Zaleska, M, Szepietowska, K, Maciejewski, K, Peller, M, Grabowski, M, Lodziński, P, et al
Kardiologia polska. 2018;(5):889-898
Abstract
BACKGROUND The first-line drugs for the treatment of non-valvular atrial fibrillation (AF) are non-vitamin K antagonist oral anticoagulants (NOACs), which are preferred over vitamin K antagonists (VKAs). There is some evidence that there are dis-crepancies between everyday clinical practice and the guidelines. AIM: The study aimed to compare the characteristics of patients on VKAs, dabigatran, and rivaroxaban in everyday practice (i.e. baseline characteristics, drug doses, risk factors for bleeding and thromboembolic events). Additionally, we assessed the frequency of prescription of different oral anticoagulants (OACs) in recent years. METHODS This study consisted of data from the multicentre CRAFT (MultiCentre expeRience in AFib patients Treated with OAC) study (NCT02987062). This was a retrospective analysis of hospital records of AF patients (hospitalised in the years 2011-2016) treated with VKAs (acenocoumarol, warfarin) and NOACs (dabigatran, rivaroxaban). A total of 3528 patients with non-valvular AF were enrolled in the CRAFT study. RESULTS The total cohort consisted of 1973 patients on VKA, 504 patients on dabigatran, and 1051 patients on rivaroxaban. Patients on rivaroxaban were older (70.5 ± 13.1 years) and more often female (47.9%), compared with those on VKAs (67.0 ± 12.8 years, p < 0.001; 35.5%, p < 0.001) and on dabigatran (66.0 ± 13.9 years, p < 0.001; 38.9%, p = 0.001). Among NOACs, patients with persistent and permanent AF were more likely to receive rivaroxaban (54.7% and 73.4%, re-spectively) than dabigatran (45.3%, p < 0.001 and 26.6%, p = 0.002, respectively). Patients on rivaroxaban had higher risk of thromboembolic events (CHA2DS2VASc 3.9 ± 2.0, CHADS2 2.2 ± 1.4) than those on VKAs (3.3 ± 2.0, 1.9 ± 1.3) and on dabigatran (3.1 ± 2.0, 1.8 ± 1.3). Patients on rivaroxaban had also a higher rate of prior major bleeding (11.2%) than those on VKAs (6.7%, p < 0.001) and on dabigatran (7.3%, p = 0.02). Patients on lower doses of dabigatran and rivaroxaban had a significantly higher risk of thromboembolic and bleeding events. Use of VKAs in the year 2011 was reported in over 96% of patients on OACs, but this proportion decreased to 34.6% in 2016. In the last analysed year (2016) AF patients were treated mainly with NOACs - dabigatran (24.2%) and rivaroxaban (41.3%). CONCLUSIONS The prescription of VKAs declined significantly after the introduction of NOACs. Patients treated with different OACs demonstrated a distinct baseline clinical profile. The highest risk of thromboembolic events and incidence of major bleedings was observed in patients on rivaroxaban, in comparison to patients on VKAs and dabigatran. Among NOACs, patients treated with lower doses of dabigatran and rivaroxaban were older and had a significantly higher risk of thromboembolic and bleeding events.
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Prediction of major and clinically relevant bleeding in patients with VTE treated with edoxaban or vitamin K antagonists.
Di Nisio, M, Raskob, G, Büller, HR, Grosso, MA, Zhang, G, Winters, SM, Cohen, A
Thrombosis and haemostasis. 2017;(4):784-793
Abstract
Better understanding of risk factors for major bleeding events during anticoagulant treatment for venous thromboembolism (VTE) may help physicians when deciding on intensity and duration of treatment. The primary aim of this study was to identify risk factors for major and clinically relevant bleeding in patients receiving the oral factor Xa inhibitor edoxaban or warfarin for the treatment of acute VTE. We analysed data from 8240 patients who received ≥1 dose of study drug in the Hokusai-VTE study. Bleeding risk factors were evaluated in 4118 patients who received edoxaban and significant variables were combined in a prediction model. We used the C-statistic to estimate model discrimination and bootstrap techniques for internal validation. Major bleeding occurred in 56/4118 (1.4 %) patients given edoxaban and in 66/4122 (1.6 %) patients given warfarin. Clinically relevant bleeding occurred in 349 (8.5 %) and 423 (10.3 %), respectively. Significant risk factors for major bleeding during edoxaban treatment were female sex, concomitant antiplatelet therapy, haemoglobin ≤10 g/dl, history of arterial hypertension, and systolic blood pressure >160 mmHg. The discrimination of the model was high (C-statistic: 0.71) for major bleeding, lower for clinically relevant bleeding (C-statistic: 0.62) and when the model was applied to patients receiving warfarin (C-statistic 0.60). In conclusion, we identified five main predictors of major bleeding in patients receiving edoxaban for the treatment of acute VTE. A risk model based on these factors predicted an increased risk of bleeding with good discrimination.
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Major bleeding risk among non-valvular atrial fibrillation patients initiated on apixaban, dabigatran, rivaroxaban or warfarin: a "real-world" observational study in the United States.
Lip, GY, Pan, X, Kamble, S, Kawabata, H, Mardekian, J, Masseria, C, Bruno, A, Phatak, H
International journal of clinical practice. 2016;(9):752-63
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BACKGROUND Limited data are available about the real-world safety of non-vitamin K antagonist oral anticoagulants (NOACs). OBJECTIVES To compare the major bleeding risk among newly anticoagulated non-valvular atrial fibrillation (NVAF) patients initiating apixaban, warfarin, dabigatran or rivaroxaban in the United States. METHODS AND RESULTS A retrospective cohort study was conducted to compare the major bleeding risk among newly anticoagulated NVAF patients initiating warfarin, apixaban, dabigatran or rivaroxaban. The study used the Truven MarketScan(®) Commercial & Medicare supplemental US database from 1 January 2013 through 31 December 2013. Major bleeding was defined as bleeding requiring hospitalisation. Cox model estimated hazard ratios (HRs) of major bleeding were adjusted for age, gender, baseline comorbidities and co-medications. Among 29 338 newly anticoagulated NVAF patients, 2402 (8.19%) were on apixaban; 4173 (14.22%) on dabigatran; 10 050 (34.26%) on rivaroxaban; and 12 713 (43.33%) on warfarin. After adjusting for baseline characteristics, initiation on warfarin [adjusted HR (aHR): 1.93, 95% confidence interval (CI): 1.12-3.33, P=.018] or rivaroxaban (aHR: 2.19, 95% CI: 1.26-3.79, P=.005) had significantly greater risk of major bleeding vs apixaban. Dabigatran initiation (aHR: 1.71, 95% CI: 0.94-3.10, P=.079) had a non-significant major bleeding risk vs apixaban. When compared with warfarin, apixaban (aHR: 0.52, 95% CI: 0.30-0.89, P=.018) had significantly lower major bleeding risk. Patients initiating rivaroxaban (aHR: 1.13, 95% CI: 0.91-1.41, P=.262) or dabigatran (aHR: 0.88, 95% CI: 0.64-1.21, P=.446) had a non-significant major bleeding risk vs warfarin. CONCLUSION Among newly anticoagulated NVAF patients in the real-world setting, initiation with rivaroxaban or warfarin was associated with a significantly greater risk of major bleeding compared with initiation on apixaban. When compared with warfarin, initiation with apixaban was associated with significantly lower risk of major bleeding. Additional observational studies are required to confirm these findings.
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Long-term Clinical Outcomes of Splanchnic Vein Thrombosis: Results of an International Registry.
Ageno, W, Riva, N, Schulman, S, Beyer-Westendorf, J, Bang, SM, Senzolo, M, Grandone, E, Pasca, S, Di Minno, MN, Duce, R, et al
JAMA internal medicine. 2015;(9):1474-80
Abstract
IMPORTANCE Little information is available on the long-term clinical outcome of patients with splanchnic vein thrombosis (SVT). OBJECTIVE To assess the incidence rates of bleeding, thrombotic events, and mortality in a large international cohort of patients with SVT. DESIGN, SETTING, AND PARTICIPANTS A prospective cohort study was conducted beginning May 2, 2008, and completed January 30, 2014, at hospital-based centers specialized in the management of thromboembolic disorders; a 2-year follow-up period was completed January 30, 2014, and data analysis was conducted from July 1, 2014, to February 28, 2015. Participants included 604 consecutive patients with objectively diagnosed SVT; there were no exclusion critieria. Information was gathered on baseline characteristics, risk factors, and antithrombotic treatment. Clinical outcomes during the follow-up period were documented and reviewed by a central adjudication committee. MAIN OUTCOMES AND MEASURES Major bleeding, defined according to the International Society on Thrombosis and Hemostasis; bleeding requiring hospitalization; thrombotic events, including venous and arterial thrombosis; and all-cause mortality. RESULTS Of the 604 patients (median age, 54 years; 62.6% males), 21 (3.5%) did not complete follow-up. The most common risk factors for SVT were liver cirrhosis (167 of 600 patients [27.8%]) and solid cancer (136 of 600 [22.7%]); the most common sites of thrombosis were the portal vein (465 of 604 [77.0%]) and the mesenteric veins (266 of 604 [44.0%]). Anticoagulation was administered to 465 patients in the entire cohort (77.0%) with a mean duration of 13.9 months; 175 of the anticoagulant group (37.6%) received parenteral treatment only, and 290 patients (62.4%) were receiving vitamin K antagonists. The incidence rates (reported with 95% CIs) were 3.8 per 100 patient-years (2.7-5.2) for major bleeding, 7.3 per 100 patient-years (5.8-9.3) for thrombotic events, and 10.3 per 100 patient-years (8.5-12.5) for all-cause mortality. During anticoagulant treatment, these rates were 3.9 per 100 patient-years (2.6-6.0) for major bleeding and 5.6 per 100 patient-years (3.9-8.0) for thrombotic events. After treatment discontinuation, rates were 1.0 per 100 patient-years (0.3-4.2) and 10.5 per 100 patient-years (6.8-16.3), respectively. The highest rates of major bleeding and thrombotic events during the whole study period were observed in patients with cirrhosis (10.0 per 100 patient-years [6.6-15.1] and 11.3 per 100 patient-years [7.7-16.8], respectively); the lowest rates were in patients with SVT secondary to transient risk factors (0.5 per 100 patient-years [0.1-3.7] and 3.2 per 100 patient-years [1.4-7.0], respectively). CONCLUSIONS AND RELEVANCE Most patients with SVT have a substantial long-term risk of thrombotic events. In patients with cirrhosis, this risk must be balanced against a similarly high risk of major bleeding. Anticoagulant treatment appears to be safe and effective in most patients with SVT.
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Comparison of the short-term risk of bleeding and arterial thromboembolic events in nonvalvular atrial fibrillation patients newly treated with dabigatran or rivaroxaban versus vitamin K antagonists: a French nationwide propensity-matched cohort study.
Maura, G, Blotière, PO, Bouillon, K, Billionnet, C, Ricordeau, P, Alla, F, Zureik, M
Circulation. 2015;(13):1252-60
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BACKGROUND The safety and effectiveness of non-vitamin K antagonist (VKA) oral anticoagulants, dabigatran or rivaroxaban, were compared with VKA in anticoagulant-naive patients with nonvalvular atrial fibrillation during the early phase of anticoagulant therapy. METHODS AND RESULTS With the use of the French medico-administrative databases (SNIIRAM and PMSI), this nationwide cohort study included patients with nonvalvular atrial fibrillation who initiated dabigatran or rivaroxaban between July and November 2012 or VKA between July and November 2011. Patients presenting a contraindication to oral anticoagulants were excluded. Dabigatran and rivaroxaban new users were matched to VKA new users by the use of 1:2 matching on the propensity score. Patients were followed for up to 90 days until outcome, death, loss to follow-up, or December 31 of the inclusion year. Hazard ratios of hospitalizations for bleeding and arterial thromboembolic events were estimated in an intent-to-treat analysis using Cox regression models. The population was composed of 19 713 VKA, 8443 dabigatran, and 4651 rivaroxaban new users. All dabigatran- and rivaroxaban-treated patients were matched to 16 014 and 9301 VKA-treated patients, respectively. Among dabigatran-, rivaroxaban-, and their VKA-matched-treated patients, 55 and 122 and 31 and 68 bleeding events and 33 and 58 and 12 and 28 arterial thromboembolic events were observed during follow-up, respectively. After matching, no statistically significant difference in bleeding (hazard ratio, 0.88; 95% confidence interval, 0.64-1.21) or thromboembolic (hazard ratio, 1.10; 95% confidence interval, 0.72-1.69) risk was observed between dabigatran and VKA new users. Bleeding (hazard ratio, 0.98; 95% confidence interval, 0.64-1.51) and ischemic (hazard ratio, 0.93; 95% confidence interval, 0.47-1.85) risks were comparable between rivaroxaban and VKA new users. CONCLUSIONS In this propensity-matched cohort study, our findings suggest that physicians should exercise caution when initiating either non-VKA oral anticoagulants or VKA in patients with nonvalvular atrial fibrillation.