Protective effects of oral anticoagulants on cerebrovascular diseases and cognitive impairment in patients with atrial fibrillation: protocol for a multicentre, prospective, observational, longitudinal cohort study (Strawberry study).
ABSTRACT: INTRODUCTION:Non-valvular atrial fibrillation (NVAF) is known as a robust risk factor for stroke. Recent reports have suggested a risk of dementia with NVAF, but much remains unknown regarding the relationship between this mechanism and the potential protective effects of novel anticoagulants (direct oral anticoagulants (DOACs), or non-vitamin K oral anticoagulants). METHODS AND ANALYSIS:This study, the strategy to obtain warfarin or DOAC's benefit by evaluating registry, is an investigator-initiated, multicentre, prospective, observational, longitudinal cohort study comparing the effects of warfarin therapy and DOACs on cerebrovascular diseases and cognitive impairment over an estimated duration of 36 months. Once a year for 3 years, the activities of daily living and cognitive functioning of non-demented patients with NVAF will be assessed. Demographics, risk factors, laboratory investigations, lifestyle, social background and brain MRI will be assessed. ETHICS AND DISSEMINATION:This protocol has been approved by the ethics committee of the National Center for Geriatrics and Gerontology (No. 1017) and complies with the Declaration of Helsinki. Informed consent will be obtained before study enrolment and only coded data will be stored in a secured database. The results will be published in peer-reviewed journals and presented at scientific meetings to ensure the applicability of the findings in clinical practice. TRIAL REGISTRATION NUMBER:UMIN000025721.
Project description:Background:Direct oral anticoagulants (DOACs) are indicated for prevention of stroke and embolism in patients with nonvalvular atrial fibrillation (NVAF). These agents have been shown to be non-inferior to warfarin in terms of efficacy and safety. However, their uptake in practice has been variable, and prescribed dosages may be inconsistent with manufacturer recommendations. Objectives:To evaluate patterns of oral anticoagulant use in patients with NVAF, including determination of patient characteristics associated with the prescribing of warfarin or DOACs and whether prescribed dosages of DOACs were concordant with manufacturer recommendations. Methods:This retrospective chart review was conducted from April to September 2017 at Abbotsford Regional Hospital, Abbotsford, British Columbia. Patients at least 18 years of age with NVAF and CHADS-65 score of 1 or higher were included. Patients with contraindications to oral anticoagulants, those with reversible atrial fibrillation, and those undergoing renal dialysis were excluded. The dosage of DOACs was categorized as too low, too high, or correct in relation to manufacturer recommendations for the Canadian product. Results:A total of 120 patients were included. At discharge, 83 (69%) of the patients had a prescription for DOAC, 25 (21%) had a prescription for warfarin, and 12 (10%) had no prescription for an oral anticoagulant. There were no statistically significant differences between the warfarin and DOAC groups with respect to patient characteristics. Among the 56 patients for whom a full DOAC dose was indicated, 7 (13%) received a dose that was too low. Among the 23 patients for whom a full DOAC dose was not indicated, 4 (17%) received a dose that was too high. Conclusions:At the study hospital, most patients with NVAF and CHADS-65 score of at least 1 had a discharge prescription for DOAC. Patient characteristics appeared to be similar between the warfarin and DOAC groups. For a notable proportion of patients who received a DOAC, the dosage was incorrect. Appropriate prescribing of oral anticoagulants could be further improved by education for prescribers and involvement of hospital pharmacists.
Project description:Nonvalvular atrial fibrillation- (NVAF-) related stroke and venous thromboembolism (VTE) are cardiovascular diseases associated with significant morbidity and economic burden. The historical standard treatment of VTE has been the administration of parenteral heparinoid until oral warfarin therapy attains a therapeutic international normalized ratio. Warfarin has been the most common medication for stroke prevention in NVAF. Warfarin use is complicated by a narrow therapeutic window, unpredictable dose response, numerous food and drug interactions, and requirements for frequent monitoring. To overcome these disadvantages, direct-acting oral anticoagulants (DOACs)-dabigatran, rivaroxaban, apixaban, and edoxaban-have been developed for the prevention of stroke or systemic embolic events (SEE) in patients with NVAF and for the treatment of VTE. Advantages of DOACs include predictable pharmacokinetics, few drug-drug interactions, and low monitoring requirements. In clinical studies, DOACs are noninferior to warfarin for the prevention of NVAF-related stroke and the treatment and prevention of VTE as well as postoperative knee and hip surgery VTE prophylaxis, with decreased bleeding risks. This review addresses the practical considerations for the emergency physician in DOAC use, including dosing recommendations, laboratory monitoring, anticoagulation reversal, and cost-effectiveness. The challenges of DOACs, such as the lack of specific laboratory measurements and antidotes, are also discussed.
Project description:Direct oral anticoagulants (DOACs) are at least as efficacious and safe as warfarin among non-valvular atrial fibrillation (NVAF) patients; limited evidence is available regarding NVAF patients with heart failure (HF). US Medicare enrollees with NVAF and HF initiating DOACs (apixaban, rivaroxaban, dabigatran) or warfarin were selected. Propensity score matching and Cox models were used to estimate the risk of stroke/systemic embolism (SE), major bleeding (MB), and major adverse cardiac events (MACE) comparing DOACs versus warfarin and DOACs versus DOACs. We identified 10,570 apixaban-warfarin, 4,297 dabigatran-warfarin, 15,712 rivaroxaban-warfarin, 4,263 apixaban-dabigatran, 10,477 apixaban-rivaroxaban, and 4,297 dabigatran-rivaroxaban matched pairs. Compared to warfarin, apixaban had lower rates of stroke/SE (hazard ratio = 0.64, 95% confidence interval = 0.48-0.85), MB (hazard ratio = 0.66, 0.58-0.76), and MACE (hazard ratio = 0.73,0.67-0.79); dabigatran and rivaroxaban had lower rates of MACE (hazard ratio = 0.87,0.77-0.99; hazard ratio = 0.84, 0.79-0.89, respectively). Rivaroxaban had a lower stroke/SE rate (hazard ratio = 0.65, 0.52-0.81) and higher MB rate (hazard ratio = 1.18, 1.08-1.30) versus warfarin. Compared to dabigatran and rivaroxaban, apixaban had lower MB (hazard ratio = 0.71, 0.57-0.89; hazard ratio = 0.55, 0.49-0.63) and MACE rates (hazard ratio = 0.80, 0.69-0.93; hazard ratio = 0.86, 0.79-0.94), respectively. All DOACs had lower MACE rates versus warfarin; differences were observed in stroke/SE and MB. Our findings provide insights about OAC therapy among NVAF patients with HF.
Project description:BACKGROUND:Increasing age is associated with an increase in stroke in patients with nonvalvular atrial fibrillation (NVAF). Elderly patients have several comorbidities and increased bleeding risk. OBJECTIVE:The aim of this study was to evaluate the clinical outcomes of Japanese patients with NVAF aged???85 years who were treated with direct oral anticoagulants (DOACs) or warfarin. METHODS:We retrospectively studied the records of 358 patients with NVAF aged???85 years who had taken DOACs or warfarin between 2014 and 2018. The primary endpoints were the first occurrences of thromboembolic and bleeding events and death. The secondary endpoint was the discontinuation of oral anticoagulation (OAC) therapy. RESULTS:During a median follow-up period of 17 months, 24 patients died. The incidence (per 100 patient-years [PY]) of thromboembolic events was 1.8 in patients treated with DOACs and 2.2 in those treated with warfarin (adjusted subdistribution hazard ratio [SHR] 0.69; 95% confidence interval [CI] 0.23-2.12 in a competing model), and the incidence of major bleeding events was 3.1 and 4.2 in patients treated with DOACs and warfarin, respectively (adjusted SHR 0.95; 95% CI 0.32-2.86). The most common cause of bleeding events was gastrointestinal bleeding. A total of 33 patients permanently discontinued OAC therapy, at a median age of 89 years and with no differences between DOACs and warfarin. The most common reason for discontinuing OAC therapy was bleeding events. CONCLUSION:Our results revealed that the incidences of thromboembolism and major bleeding among patients with NVAF aged???85 years were similar for those treated with DOACs and those treated with warfarin. Approximately 10% of patients permanently discontinued OAC therapy.
Project description:Atrial fibrillation (AF) prevalence increases with age; >?80% of US adults with AF are aged ??65 years. Compare the risk of stroke/systemic embolism (SE), major bleeding (MB), net clinical outcome (NCO), and major adverse cardiac events (MACE) among elderly non-valvular AF (NVAF) Medicare patients prescribed direct oral anticoagulants (DOACs) VS warfarin. NVAF patients aged ??65 years who initiated DOACs (apixaban, dabigatran, and rivaroxaban) or warfarin were selected from 01JAN2013-31DEC2015 in CMS Medicare data. Propensity score matching was used to balance DOAC and warfarin cohorts. Cox proportional hazards models estimated the risk of stroke/SE, MB, NCO, and MACE. 37,525 apixaban-warfarin, 18,131 dabigatran-warfarin, and 55,359 rivaroxaban-warfarin pairs were included. Compared to warfarin, apixaban (HR: 0.69; 95% CI 0.59-0.81) and rivaroxaban (HR: 0.82; 95% CI 0.73-0.91) had lower risk of stroke/SE, and dabigatran (HR: 0.88; 95% CI 0.72-1.07) had similar risk of stroke/SE. Apixaban (MB: HR: 0.61; 95% CI 0.57-0.67; NCO: HR: 0.64; 95% CI 0.60-0.69) and dabigatran (MB: HR: 0.79; 95% CI 0.71-0.89; NCO: HR: 0.84; 95% CI 0.76-0.93) had lower risk of MB and NCO, and rivaroxaban had higher risk of MB (HR: 1.08; 95% CI 1.02-1.14) and similar risk of NCO (HR: 1.04; 95% CI 0.99-1.09). Compared to warfarin, apixaban had a lower risk for stroke/SE, MB, and NCO; dabigatran had a lower risk of MB and NCO; and rivaroxaban had a lower risk of stroke/SE but higher risk of MB. All DOACs had lower risk of MACE compared to warfarin.
Project description:BACKGROUND:Real-world effectiveness and safety of antithrombotics in nonvalvular atrial fibrillation (NVAF) patients in Singapore has not been thoroughly studied. HYPOTHESIS:Users of various antithrombotics experience a significantly different risk of stroke and major bleed compared with warfarin users. METHODS:This multicenter retrospective cohort study included patients age ≥ 21 years newly diagnosed with NVAF between July 2012 and September 2015. Using electronic medical records, data on patients' demographics, antithrombotics prescribed, and CHA2 DS2 -VASc and HAS-BLED risk factors were collected. Patients were followed for 1 year from diagnosis for the primary effectiveness and safety endpoints of incident stroke or systemic embolism and major bleed, respectively. The secondary safety endpoint was overall bleed. Hazard ratios (HR) were determined from Cox regression. RESULTS:Of 743 patients included, 224 were on warfarin, 156 on direct oral anticoagulants (DOACs), 277 on single antiplatelet therapy (SAPT), 28 on dual antiplatelet therapy (DAPT), and 58 on no therapy. Mean age (±SD) was 68.7 ± 13.0 years. Compared with warfarin users, SAPT (adjusted [adj.] HR: 3.70, 95% confidence interval [CI]: 1.21-11.3) and DAPT users (adj. HR: 10.1, 95% CI: 1.51-67.2) were more likely to develop thromboembolic outcomes. Also, DOAC users (adj. HR: 0.304, 95% CI: 0.158-0.585), SAPT users (adj. HR: 0.142, 95% CI: 0.0680-0.295), and DAPT users (adj. HR: 0.112, 95% CI: 0.0146-0.857) were less likely to experience any bleed compared with warfarin users. CONCLUSIONS:SAPT and DAPT are less effective than warfarin in NVAF patients. DOACs may be considered in view of lower risk of overall bleed.
Project description:BACKGROUND:Clinical trials have demonstrated that direct oral anticoagulants (DOACs) are at least non-inferior to warfarin in reducing the risk of stroke/systemic embolism (SE) among patients with non-valvular atrial fibrillation (NVAF), but the comparative risk of major bleeding varies between DOACs and warfarin. Using US Department of Defense (DOD) data, this study compared the risk of stroke/SE and major bleeding for DOACs relative to warfarin. METHODS:Adult patients with ≥1 pharmacy claim for apixaban, dabigatran, rivaroxaban, or warfarin from 01 Jan 2013-30 Sep 2015 were selected. Patients were required to have ≥1 medical claim for atrial fibrillation during the 12-month baseline period. Patients with a warfarin or DOAC claim during the 12-month baseline period were excluded. Each DOAC cohort was matched to the warfarin cohort using propensity score matching (PSM). Cox proportional hazards models were conducted to evaluate the risk of stroke/SE and major bleeding of each DOAC vs warfarin. RESULTS:Of 41,001 identified patients, there were 3691 dabigatran-warfarin, 8226 rivaroxaban-warfarin, and 7607 apixaban-warfarin matched patient pairs. Apixaban was the only DOAC found to be associated with a significantly lower risk of stroke/SE (hazard ratio [HR]: 0.55; 95% confidence interval [CI]: 0.39, 0.77; p < 0.001) and major bleeding (HR: 0.65; 95% CI: 0.53, 0.80; p < 0.001) compared to warfarin. Dabigatran and rivaroxaban initiation were associated with similar risk of stroke/SE (dabigatran: HR: 0.68; 95% CI: 0.43, 1.07; p = 0.096; rivaroxaban: HR: 0.83; 95% CI: 0.64, 1.09; p = 0.187) and major bleeding (dabigatran: HR: 1.05; 95% CI: 0.79, 1.40; p = 0.730; rivaroxaban: HR: 1.07; 95% CI: 0.91, 1.27; p = 0.423) compared to warfarin. CONCLUSION:Among NVAF patients in the US DOD population, apixaban was associated with significantly lower risk of stroke/SE and major bleeding compared to warfarin. Dabigatran and rivaroxaban were associated with similar risk of stroke/SE and major bleeding compared to warfarin.
Project description:Oral anticoagulants are required for both treatment and prophylaxis in many different diseases. Clinicians and patients now have a choice of oral anticoagulants, including the vitamin K antagonists (of which warfarin is the most widely used and is used as the exemplar in this paper), and direct oral anticoagulants (DOACs: dabigatran, apixaban, rivaroxaban, and edoxaban). This paper explores the recent advances and controversies in oral anticoagulation. While some commentators may favour a complete switchover to DOACs, this paper argues that warfarin still has a place in therapy, and a stratified approach that enables the correct choice of both drug and dose would improve both patient outcomes and affordability.
Project description:Direct oral anticoagulants (DOACs) are valid alternative options to vitamin K antagonists due to their limited interactions with drugs or food and the fact that they do not require regular coagulation monitoring. To this regard, recent practice guidelines recommend that DOACs should be considered as first-line anticoagulant therapy for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF). This review (1) outlines current international guidelines for the management of DOACs to prevent stroke in patients with NVAF, (2) outlines indications for elderly patients as well as specific settings including acute coronary syndromes and intracranial hemorrhage, and (3) offers a practical guide for the use of DOACs in neurological settings.
Project description:The anticoagulated trauma patient presents a particular challenge to the critical care physician. Our understanding of these patients is defined and extrapolated by experience with patients on warfarin pre-injury. Today, many patients who would have been on warfarin are now prescribed the Direct Oral Anticoagulants (DOACs) a class of anticoagulants with entirely different mechanisms of action, effects on routine coagulation assays and approach to reversal.Trauma registry data from Toronto's (Ontario, Canada) two Level 1 trauma centres were used to identify patients on oral anticoagulation pre-injury from June 1, 2014 to June 1, 2015. The trauma registry and medical records were reviewed and used to extract demographic and clinical data.We found 81 patients were on oral anticoagulants pre-injury representing 3.2% of the total trauma population and 33% of the orally anticoagulated patients were prescribed a DOAC prior to presentation. Comparison between the DOAC and warfarin groups showed similar age, mechanisms of injury, indications for anticoagulation, injury severity score and rate of intracranial hemorrhage. Patients on DOACs had higher initial mean hemoglobin vs warfarin (131 vs 120) and lower serum creatinine (94.8 vs 129.5). The percentage of patients receiving a blood transfusion in the trauma bay and total in-hospital transfusion was similar between the two groups however patients on DOACs were more likely to receive tranexamic acid vs patients on warfarin (32.1% vs 9.1%) and less likely to receive prothrombin concentrates (18.5% vs 60%). Patients on DOACs were found to have higher survival to discharge (92%) vs patients on warfarin (72%).Patients on DOACs pre-injury now represent a significant proportion of the anticoagulated trauma population. Although they share demographic and clinical similarities with patients on warfarin, patients on DOACs may have improved outcomes despite lack of established drug reversal protocols and challenging interpretation of coagulation assays.III; Study Type: Retrospective Review.