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Aims: The Edoxaban Low-Dose for Elder Care Atrial Fibrillation Patients (ELDERCARE-AF) trial showed that edoxaban at a very low dosage (VLD) of 15 mg/day was more effective than a placebo at preventing stroke/systemic embolism without significantly increasing the risk of serious bleeding. We aimed to compare the effectiveness and safety for VLD non-vitamin K antagonist oral anticoagulants (NOACs) [edoxaban 15 mg o.d., dabigatran 110 or 150 o.d., apixaban 2.5 mg o.d., or rivaroxaban 10 mg (without the diagnosis of chronic kidney disease) or <10 mg o.d.] vs. regular-dosage (RD) NOACs (edoxaban 60/30 mg o.d. or other labeling-dosage NOACs) among a real-world cohort of elderly atrial fibrillation (AF) population similar to the ELDERCARE-AF cohort., Methods and Results: In this nationwide retrospective cohort study from Taiwan National Health Insurance Research Database (NHIRD), we identified a total of 7294 and 4151 consecutive AF patients aged 80 years or older with a CHADS2 (congestive heart failure, hypertension, age 75 years or older, diabetes mellitus, previous stroke/transient ischemic attack (2 points) score ≥2 who met the enrollment criteria (generally similar to ELDERCARE-AF) taking VLD and RD NOACs from 1 June 2012 to 31 December 2019, respectively. Propensity-score stabilized weighting (PSSW) was used to balance covariates across study groups. Patients were followed up from the first date of prescription for NOACs until the first occurrence of any study outcome, death, or until the end date of the study period (31 December 2020). After PSSW, VLD NOAC was associated with a comparable risk of ischemic stroke/systemic embolism and major bleeding but a higher risk of major adverse limb events (MALEs) requiring lower limb revascularization or amputation [hazard ratio (HR): 1.54, 95% confidential interval (CI): 1.09-2.18; P = 0.014), venous thrombosis (HR: 3.75, 95% CI: 1.56-8.97; P = 0.003), and all-cause mortality (HR: 1.21, 95% CI: 1.15-1.29; P <0.001) compared with RD NOACs. VLD NOACs showed worse outcomes in most net clinical outcome (NCO) benefits. The main result was consistent based on on-treatment analysis or accounting for death as a competing risk. In general, the advantage of NCOs for the RD NOACs over VLD NOACs persisted in most high-risk subgroups, consistent with the main analysis (P for interaction > 0.05)., Conclusion: Use of VLD NOACs was associated with a greater risk of arterial and venous thrombosis, death as well as the composite outcomes, when compared with that of RD NOAC in high-risk elderly AF patients at increased bleeding risk. Thromboprophylaxis with RD NOAC is still preferable over VLD NOAC for the majority of elderly AF patients at increased bleeding risk., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Objective: Hemoglobin levels and platelet counts have been associated with adverse clinical outcomes in patients with cardiovascular conditions. We aimed to assess the impact of oral anticoagulant use for patients with atrial fibrillation and concomitant anemia or thrombocytopenia., Methods: We used medical data from a multicenter health care system in Taiwan including 37,074 patients with atrial fibrillation. Patients were categorized into 3 groups based on hemoglobin and platelet levels: Group 1 (hemoglobin >10g/dL and platelet>100 K/µL; n = 29,147), Group 2 (hemoglobin<10 g/dL or platelet<100 K/µL; n = 7078), and Group 3 (hemoglobin <10 g/dL and platelet <100 K/µL; n = 849). Patients in each category were further stratified as 3 groups according to their stroke prevention strategies: no oral anticoagulant use (non-OAC), warfarin, or nonvitamin K antagonist oral anticoagulants (NOACs)., Results: A higher hemoglobin or platelet level was associated with a higher risk of ischemic stroke/systemic embolism but lower risks of intracranial hemorrhage and major bleeding. The composite risks of ischemic stroke/systemic embolism, intracranial hemorrhage and major bleeding were higher in Group 3 or Group 2, compared with Group 1 (6.79% a year vs 6.41% year vs 4.13% year). Compared to non-OACs, warfarin was not associated with a lower composite risk in the 3 groups. NOACs were associated with a lower composite risk in Group 1 (adjusted hazard ratio:0.68, [95% confidence interval:0.60-0.76]) and Group 2 (adjusted hazard ratio:0.73, [95% confidence interval:0.53-0.99]) but was nonsignificant in Group 3., Conclusions: Patients with atrial fibrillation with anemia or thrombocytopenia were a high-risk population. Compared with no OAC use, NOACs were associated with better clinical outcomes for patients with atrial fibrillation and advanced anemia (hemoglobin <10g/dL) or thrombocytopenia (platelet <100 K/µL) but not for those with both conditions., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Off-label dosing non-vitamin K antagonist oral anticoagulants (NOACs) are commonly prescribed for Asian patients with atrial fibrillation (AF)., Objective: The purpose of this study was to investigate the associations between inappropriate dosing of NOACs and clinical outcomes., Methods: We used medical data from a multicenter health care system in Taiwan, which included 2068, 5135, 2589, 1483, and 2342 AF patients taking dabigatran, rivaroxaban, apixaban, edoxaban, and warfarin, respectively. The risks of ischemic stroke/systemic embolism (IS/SE) and major bleeding in patients treated with underdosing or overdosing NOACs were compared to those of on-label dosing NOACs and warfarin., Results: About 27% and 5% of AF patients were treated with underdosing and overdosing NOACs, respectively. Compared to on-label dosing, underdosing NOACs were associated with a significantly higher risk of IS/SE (adjusted hazard ratio [aHR] 1.59; 95% confidence interval [CI] 1.25-2.02; P <.001), whereas overdosing NOACs were associated with a significantly higher risk of major bleeding (aHR 2.01; 95% CI 1.13-3.56; P = .017). Compared to warfarin, the 4 on-label dosing NOACs were associated with a comparable risk of IS/SE and a significantly lower risk of major bleeding, whereas underdosing NOACs were associated with a higher risk of IS/SE (aHR 1.46; P = .012)., Conclusion: About 3 in 10 Asian AF patients were treated with off-label dosing NOACs in daily practice. Compared to on-label dosing, underdosing was associated with a higher risk of IS/SE, whereas overdosing was associated with a higher risk of major bleeding. Thus, even for Asian AF patients at higher risk for bleeding, NOACs still should be prescribed at the dosing based on clinical trial criteria and guideline recommendations., (Copyright © 2020 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Studies specifically examining the association between glycated hemoglobin A1c (HbA1c) levels and ischemic stroke/systemic thromboembolism (IS/SE) risk in atrial fibrillation (AF) patients are limited. Here, we investigated the association between HbA1c levels and the risk of IS/SE, as well as major bleeding, among AF patients with or without oral anticoagulants (OACs). We also compared the effectiveness and safety of warfarin and direct oral anticoagulants (DOACs) in different HbA1c categories., Methods: We utilized medical data from a multi-center healthcare provider in Taiwan, which included 34,036 AF patients with serum HbA1c data available within 3 months after AF being diagnosed. Patients were divided into seven study groups according to their HbA1c levels: < 5.4%, 5.4%-5.6%, 5.7%-5.9%, 6.0%-6.4%, 6.5%-6.9%, 7.0%-7.9%, and ≥ 8.0%. The risks of IS/SE and major bleeding were compared among the groups after adjusting for baseline stroke and bleeding risk factors., Results: Compared with the patients with HbA1c level < 5.4%, IS/SE risk significantly increased at HbA1c levels higher than 6.5% [adjusted hazard ratio (HR): 1.20, 95% confidence interval (CI): 1.00-1.43 for HbA1c level 6.5%-6.9%; 1.32, (95% CI 1.11-1.57) for HbA1c level 7.0%-7.9%; and 1.48 (95% CI 1.25-1.76) for HbA1c level ≥ 8.0%]. These results were generally consistent in AF patients without OACs (n = 24,931). However, among 9105 patients receiving OACs, IS/SE risk was not higher for patients having higher HbA1c levels. The risk of major bleeding was comparable across all HbA1c categories. Compared with warfarin, DOACs were associated with lower risks of IS/SE (adjusted HR: 0.61, 95% CI 0.49-0.75) and major bleeding (adjusted HR: 0.30, 95% CI 0.21-0.42) without interactions across different HbA1c categories (all P interactions > 0.05)., Conclusion: For AF patients, IS/SE risk significantly increased once HbA1c levels exceeded 6.5%, and OACs may attenuate these associations. Compared with warfarin, DOACs were more effective and safer across broad HbA1c categories. Therefore, in addition to prescribing DOACs when indicated, more aggressive glycemic control to achieve an HbA1c level < 6.5% may be considered for eligible AF patients and should be tested in further prospective studies.

Background: Whether four direct oral anticoagulants (DOACs) are superior to warfarin among Asians with non-valvular atrial fibrillation (NVAF) remains unclear in the real-world setting., Methods: We searched PubMed and Medline + Journals@Ovid + EMBASE from September 17, 2009 to May 4, 2019 to perform a systematic review and meta-analysis of all observational real-world studies comparing four DOACs with warfarin specifically focused on Asian patients with NVAF., Results: From the original 212 results retrieved, 18 studies were included in the meta-analysis. Overall, DOACs were associated with lower risks of thromboembolism (hazard ratio; [95% confidence interval], 0.70; [0.63-0.78]), acute myocardial infarction (0.67; [0.57-0.79]), all-cause mortality (0.62; [0.56-0.69]), major bleeding (0.59; [0.50-0.69]), intracranial hemorrhage (0.50; [0.40-0.62]), gastrointestinal bleeding (0.66; [0.46-0.95]), and any bleeding (0.82; [0.73-0.92]) than warfarin. There was statistic heterogeneity between DOACs for the risks of thromboembolism (P interaction = 0.03) and acute myocardial infarction (P interaction = 0.007) when compared to warfarin. However, all DOACs showed lower risks of thromboembolism and acute myocardial infarction than warfarin when pooling studies that compared individual DOAC with warfarin. With regard to the other outcomes when compared to warfarin, there was no statistical heterogeneity between DOACs. In addition, the effectiveness and safety of four DOACs versus warfarin persisted in the subgroups of either standard-dose or low-dose DOACs., Conclusions: The meta-analysis shows that the DOACs had greater effectiveness and safety compared to warfarin in real-world practice for stroke prevention, among Asian patients with NVAF.

Background: Whether four direct oral anticoagulants (DOACs) are superior to warfarin in Asian patients with nonvalvular atrial fibrillation (NVAF) remains unclear., Methods: This nationwide retrospective cohort study was based on data from Taiwan's National Health Insurance Research Database from June 1, 2012, to December 31, 2017, covering patients with NVAF taking edoxaban (n = 4,577), apixaban (n = 9,952), rivaroxaban (n = 33,022), dabigatran (n = 22,371), and warfarin (n = 19,761). Propensity score weighting was used to balance covariates across study groups. Patients were followed up until occurrence of study outcomes or end date of study., Results: Edoxaban, apixaban, and rivaroxaban were associated with a lower risk of ischemic stroke/systemic embolism than warfarin. All DOACs had a lower risk of major bleeding than warfarin. Apixaban was associated with a lower risk of major bleeding than rivaroxaban and dabigatran, whereas the risk of major bleeding was comparable between edoxaban and apixaban. The reduced risks of thromboembolism/major bleeding for the four DOACs persisted in high-risk subgroups, including those with chronic kidney disease, elderly patients (age ≥ 75 years), secondary stroke prevention, or CHA 2 DS 2 -VASc score (congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, previous stroke/transient ischemic attack, vascular disease, age 65-74 years, and female sex) ≥ 4. A total of 2,924 (64%), 6,359 (64%), 31,108 (94%), and 19,821 (89%) patients received low-dose edoxaban (15-30 mg/d), apixaban (2.5 mg bid), rivaroxaban (10-15 mg/d), and dabigatran (110 mg bid), respectively. The effectiveness/safety outcomes with the four low-dose DOACs compared with warfarin were consistent with the main analysis., Conclusions: In the largest real-world practice study among Asian patients with NVAF, four DOACs were associated with a comparable or lower risk of thromboembolism, and a lower risk of bleeding than warfarin. There was consistency even among high-risk subgroups and whether standard-or low-dose regimens were compared., (Copyright © 2019 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Background Liver cirrhotic patients with nonvalvular atrial fibrillation have been excluded from randomized clinical studies regarding oral anticoagulants for stroke prevention. Whether non-vitamin K antagonist oral anticoagulants ( NOAC s) are superior to warfarin for these patients remains unclear. Methods and Results This nationwide retrospective cohort study, with data collected from the Taiwan National Health Insurance Research Database, enrolled 2428 liver cirrhotic patients with nonvalvular atrial fibrillation taking apixaban (n=171), dabigatran (n=535), rivaroxaban (n=732), or warfarin (n=990) from June 1, 2012, to December 31, 2016. We used propensity score-based stabilized weights to balance covariates across study groups. Patients were followed until the occurrence of an event or the end date of study. The NOAC group (n=1438) showed risk of ischemic stroke/systemic embolism and intracranial hemorrhage comparable to that of the warfarin group (n=990) after adjustment. The NOAC group showed significantly lower risk of gastrointestinal bleeding (hazard ratio: 0.51 [95% CI, 0.32-0.79]; P=0.0030) and all major bleeding (hazard ratio: 0.51 [95% CI, 0.32-0.74]; P=0.0003) compared with warfarin group. Overall, 90% (n=1290) of patients were taking a low-dose NOAC (apixaban 2.5 mg twice daily, rivaroxaban 10-15 mg daily, or dabigatran 110 mg twice daily). The subgroup analysis indicated that both dabigatran and rivaroxaban showed lower risk of all major bleeding than warfarin. The advantage of lower gastrointestinal and all major bleeding with NOACs over warfarin is contributed by those subgroups with either nonalcoholic or nonadvanced liver cirrhosis. Conclusions NOACs have a risk of thromboembolism comparable to that of warfarin and a lower risk of major bleeding among liver cirrhotic Asian patients with nonvalvular atrial fibrillation. Consequently, thromboprophylaxis with low-dose NOAC s may be considered for such patients.

Cerebral tissue oxygen saturation (SctO2) reflects cerebral perfusion and tissue oxygen consumption, which decline in some patients with heart failure with reduced ejection fraction (HFrEF) or stroke, especially during exercise. Its physiologic basis and clinical significance remain unclear. We aimed to investigate the association of SctO2 with oxygen transport physiology and known prognostic factors during both rest and exercise in patients with HFrEF or stroke. Thirty-four HFrEF patients, 26 stroke patients, and 17 healthy controls performed an incremental cardiopulmonary exercise test using a bicycle ergometer. Integrated near-infrared spectroscopy and automatic gas analysis were used to measure cerebral tissue oxygenation and cardiac and ventilatory parameters. We found that SctO2 (rest; peak) were significantly lower in the HFrEF (66.3±13.3%; 63.4±13.8%,) than in the stroke (72.1±4.2%; 72.7±4.5%) and control (73.1±2.8%; 72±3.2%) groups. In the HFrEF group, SctO2 at rest (SctO2rest) and peak SctO2 (SctO2peak) were linearly correlated with brain natriuretic peptide (BNP), peak oxygen consumption ([Formula: see text]), and oxygen uptake efficiency slope (r between -0.561 and 0.677, p < 0.001). Stepwise linear regression showed that SctO2rest was determined by partial pressure of end-tidal carbon dioxide at rest (PETCO2rest), hemoglobin, and mean arterial pressure at rest (MAPrest) (adjusted R = 0.681, p < 0.05), while SctO2peak was mainly affected by peak carbon dioxide production ([Formula: see text]) (adjusted R = 0.653, p < 0.05) in patients with HFrEF. In conclusion, the study delineates the relationship of cerebral saturation and parameters associated with oxygen delivery. Moreover, SctO2peak and SctO2rest are correlated with some well-recognized prognostic factors in HFrEF, suggesting its potential prognostic value.

Importance: The heritability of atrial fibrillation (AF), the contribution of genetic and environmental factors, and the association of a family history of AF with prognosis are unclear., Objectives: To measure genetic and environmental factors in the familial aggregation of AF and to estimate the association of a family history of AF with major adverse cardiovascular events (MACE)., Design, Setting, and Participants: In this Taiwanese nationwide population-based study among more than 23 million people, a custom data set was obtained using the data of all patients having a diagnosis of AF recorded between January 1996 and December 2013 in the Taiwan National Health Insurance Research Database. The study population comprised all 23 422 955 individuals registered with the database in 2013, of whom 177 770 had a diagnosis of AF and were included in the heritability estimation. From the latter, a subgroup of patients having newly diagnosed AF with a first-degree relative affected by AF between 2000 and 2010 were selected and matched 1:4 to controls without a family history for estimating MACE-free survival. The dates of analysis were January 2010 to December 2013., Main Outcomes and Measures: The prevalence and relative risk of AF in relatives of patients with AF, as well as the relative contributions of heritability and shared and nonshared environmental factors to AF susceptibility. Also measured was MACE-free survival after AF was diagnosed., Results: In total, 1510 patients (204 [13.5%] female; mean [SD] age, 57.9 [9.2] years) had newly diagnosed AF with a first-degree relative affected by AF. Individuals with a first-degree relative affected by AF had a relative risk of 1.92 (95% CI, 1.84-1.99) for AF. The accountability for the phenotypic variance of AF was 19.9% for genetic factors (heritability), 3.5% for shared environmental factors, and 76.6% for nonshared environmental factors. After matching for age, sex, hypertension, type 2 diabetes, previous stroke, and anticoagulation, incident AF patients with vs without an affected first-degree relative had similar MACE-free survival., Conclusions and Relevance: Genetic and environmental factors were associated with AF, with nonshared environmental factors accounting for three-fourths of the phenotypic variance in Taiwan. Patients having AF with a first-degree relative affected by AF did not have more MACE. Therefore, family history may not be particularly informative in the diagnosis or management of AF.

Background: It is unclear whether the non-vitamin K antagonist oral anticoagulant agents rivaroxaban and dabigatran are superior to warfarin for efficacy and safety outcomes in Asians with nonvalvular atrial fibrillation (NVAF)., Objectives: The aim of this study was to compare the risk for thromboembolic events, bleeding, and mortality associated with rivaroxaban and dabigatran versus warfarin in Asians with NVAF., Methods: A nationwide retrospective cohort study was conducted of consecutive patients with NVAF taking rivaroxaban (n = 3,916), dabigatran (n = 5,921), or warfarin (n = 5,251) using data collected from the Taiwan National Health Insurance Research Database between February 1, 2013 and December 31, 2013. The propensity score weighting method was used to balance covariates across study groups. Patients were followed until the first occurrence of any study outcome or the study end date (December 31, 2013)., Results: A total of 3,425 (87%) and 5,301 (90%) patients were taking low-dose rivaroxaban (10 to 15 mg once daily) and dabigatran (110 mg twice daily), respectively. Compared with warfarin, both rivaroxaban and dabigatran significantly decreased the risk for ischemic stroke or systemic embolism (p = 0.0004 and p = 0.0006, respectively), intracranial hemorrhage (p = 0.0007 and p = 0.0005, respectively), and all-cause mortality (p < 0.0001 and p < 0.0001, respectively) during the short follow-up period. In comparing the 2 non-vitamin K antagonist oral anticoagulant agents with each other, no differences were found regarding risk for ischemic stroke or systemic embolism, intracranial hemorrhage, myocardial infarction, or mortality. Rivaroxaban carried a significantly higher risk for hospitalization for gastrointestinal bleeding than dabigatran (p = 0.0416), but on-treatment analysis showed that the risk for hospitalized gastrointestinal bleeding was similar between the 2 drugs (p = 0.5783)., Conclusions: In real-world practice among Asians with NVAF, both rivaroxaban and dabigatran were associated with reduced risk for ischemic stroke or systemic embolism, intracranial hemorrhage, and all-cause mortality without significantly increased risk for acute myocardial infarction or hospitalization for gastrointestinal bleeding compared with warfarin., (Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background and Purpose: Whether dabigatran is associated with different risks of cardiovascular, bleeding events, and mortality from warfarin in Asian patients with nonvalvular atrial fibrillation remains unclear., Methods: We used the Taiwan National Health Insurance Research Database to obtain 9940 and 9913 nonvalvular atrial fibrillation patients taking dabigatran and warfarin, respectively, from June 1, 2012, to December 31, 2013, as the dynamic cohort. Inverse probability of treatment weighting using propensity scores was used to balance covariates across 2 study groups. Patients were followed up until the first occurrence of any study outcome or end date of study., Results: During a median follow-up period of 0.67 years, there were 526 outcomes for dabigatran group. The hazard ratios (95% confidence intervals) comparing dabigatran with warfarin (reference) were as follows: ischemic stroke, 0.62 (0.52-0.73; P<0.0001); myocardial infarction, 0.67 (0.43-1.05; P=0.0803); intracranial hemorrhage, 0.44 (0.32-0.60; P<0.0001); major gastrointestinal bleeding, 0.99 (0.66-1.49; P=0.9658); all hospitalized major bleeding, 0.58 (0.46-0.74; P<0.0001); and all-cause mortality, 0.45 (0.38-0.53; P<0.0001). Dabigatran did not increase the risk of myocardial infarction or major gastrointestinal bleeding in all age groups when compared with warfarin. Total 8772 patients (88%) took a 110-mg dose in dabigatran group. The magnitude of effect for each outcome of 110-mg was comparable with that of 150-mg dose in the subgroup analysis., Conclusions: In real-world practice, dabigatran was associated with a reduced risk of ischemic stroke, intracranial hemorrhage, all hospitalized major bleeding, and all-cause mortality compared with warfarin in Asian patients with nonvalvular atrial fibrillation. Dabigatran did not increase the risk of major gastrointestinal bleeding or myocardial infarction compared with warfarin., (© 2016 American Heart Association, Inc.)

Background/purpose: Evidence-based guidelines have been formulated for optimal management of acute coronary syndrome (ACS). The Taiwan ACS Full Spectrum Registry aimed to evaluate the ACS management and identify the predictors of clinical outcomes of death/myocardial infarction/stroke 1 year post hospital discharge., Methods: Three thousand and eighty confirmed ACS patients enrolled in this registry were followed up for 1 year at 3-month intervals. Patient data on medical interventions as well as clinical events were recorded and analyzed by descriptive statistics., Results: One-year mortality among patients with ST-segment elevation myocardial infarction (STEMI), non-STEMI (NSTEMI) and unstable angina was 6.1%, 10.1%, and 6.2%, respectively. Use of secondary preventive therapies was suboptimal throughout the follow-up phase, especially dual antiplatelet therapy, which fell from 74.8% patients at discharge to 24.9% patients at 1-year follow-up. The odds of an adverse incidence of death/myocardial infarction/stroke 1 year after discharge was significantly reduced in patients receiving aspirin and clopidogrel for ≥9 months and was consequently higher in patients in whom dual antiplatelet therapy was discontinued or prescribed for <9 months. Chronic renal failure, in-hospital bleeding, a diagnosis of NSTEMI, and antiplatelet therapy discontinuation had a negative association with 1-year outcomes, whereas the use of drug-eluting stents and antiplatelet agents, clopidogrel and aspirin, were predictors of positive outcomes., Conclusion: There is a significant deviation from evidence-based guidelines in ACS management in Taiwan as reported in other countries. Policy adherence, especially with regard to dual antiplatelet therapy may hold the key to long-term favorable outcomes and improved survival rates in ACS patients in Taiwan., (Copyright © 2013. Published by Elsevier B.V.)

Background: It is unclear whether oral anticoagulants are beneficial for atrial fibrillation (AF) patients with low CHA2DS2-VASc score. Age could be important in determining the risk of thromboembolism in low risk AF patients (CHA2DS2-VASc score of 1 for male or 2 for female). Methods: The Taiwan National Health Insurance Research Database (NHIRD) was used and 27,521 AF patients with CHA2DS2-VASc score of 1 (male) or 2 (female) not receiving anticoagulants were acquired as the study cohort, which were classified into three age groups: 20–49, 50–64, and 65–74 years. The clinical endpoint was the occurrence of ischemic thromboembolism within one year of follow up. Results: During the follow-up of 0.94 ± 0.19 years, 385 (2.19%) male patients experienced ischemic thromboembolism, with annual rate of 2.32%. The annual risk ranged from 1.29%, 2.43% to 2.77% for male patients aged 20–49, 50–64 and 65–74 years respectively. Of the female patients, 218 (2.20%) experienced clinical event with annual rate of 2.32%. The annual risk increased from 1.87%, 2.28% to 2.64% for female patients aged 20–49, 50–64 and 65–74 years respectively. There was no difference in risk between the male patients aged 20–49 years with CHA2DS2-VASc score of 1 and overall male patients with CHA2DS2-VASc score of 0. (P = 0.631) The female patients aged 20–49 years with CHA2DS2-VASc score of 2 was associated with a higher risk of thromboembolic events than overall female patients with CHA2DS2-VASc score of 1 (HR = 1.93; P = 0.008). Conclusions: Age is important in determining the risk of thromboembolism in AF patients with single risk factor. In male patients <50 years old with CHA2DS2-VASc score of 1, the risk of ischemic thromboembolism was low. Considering the benefits and the risk of bleeding, oral anticoagulation therapy may not be favorable in these patients. [ABSTRACT FROM AUTHOR]