Clinical Trials Logo

Clinical Trial Summary

The purpose of this study is to assess safety and effectiveness of direct oral anticoagulants (DOACs) and warfarin for stroke prevention in patients with non-valvular atrial fibrillation (AF). The comparison of DOACs versus oral vitamin K antagonists, in particular warfarin, is of interest. The investigators will carry out separate population-based, matched cohort studies, using health administrative databases in seven Canadian provinces. New users of oral anticoagulants (DOACs or warfarin) for stroke prevention in non-valvular AF will be eligible to enter the cohorts. Follow-up will continue until a hospitalization or emergency department visit for a stroke. The results from the separate sites will be combined by meta-analysis to provide an overall assessment of the safety and effectiveness of the different anticoagulation regimens in stroke prevention in AF. The investigators hypothesize that DOACs and warfarin will have similar safety and effectiveness profiles.


Clinical Trial Description

The objective of this study is to assess safety and effectiveness of direct oral anticoagulants (DOACs) and warfarin for stroke prevention in patients with non-valvular atrial fibrillation (AF). A common-protocol approach will be used to conduct retrospective cohort studies using administrative health care data from seven Canadian provinces (Alberta, British Columbia, Manitoba, Nova Scotia, Ontario, Quebec, Saskatchewan). Briefly, the Canadian databases include population-level data on physician billing, diagnoses and procedures from hospital discharge abstracts, and dispensations for prescription drugs. The data in Alberta, Nova Scotia, and Ontario will be restricted to patients aged 65 years and older, as prescription data are not available for younger patients. In each jurisdiction, the investigators will assemble a base cohort that includes all patients newly prescribed an oral anticoagulant (DOAC or warfarin) for stroke prevention in AF. Study period will be from the date of the first DOAC approval for stroke prevention in AF at each site to the date of latest data availability at each site. All patients newly dispensed an oral anticoagulant (i.e. with no prescription for any oral anticoagulant in the prior year) with a diagnosis of AF within the 3 years prior to the date of the prescription will be eligible to be included into the study cohorts, given they present no exclusion criteria. The date of study cohort entry will be defined by the dispensation date of the newly prescribed oral anticoagulant. Patients will be censored at the earliest of death, end of healthcare coverage, switch from DOAC to warfarin, switch from warfarin to DOAC, initiation of hemodialysis or heart valve surgery, or the end of the study period, whichever occurs first. Exposure to a DOAC will be defined as a new prescription for a DOAC (apixaban, dabigatran, rivaroxaban) on the date of cohort entry. Exposure to warfarin will be defined as a new prescription for warfarin on the date of cohort entry. The investigators will use an analysis analogous to an intention-to-treat approach. The primary outcome will be defined as a hospitalization or emergency department visit for ischemic stroke or systemic embolization. The secondary outcomes will be: 1) major bleeding; 2) a composite of stroke (ischemic or hemorrhagic), systemic embolization, major bleeding or all-cause mortality; 3) myocardial infarction; 4) gastrointestinal bleeding; 5) intracranial bleeding; and 6) all-cause mortality. The study cohort will be analyzed using a matched cohort design, where DOAC users will be matched 1:1 to warfarin users on sex, age, cohort entry date, and propensity score (which will be constructed using a multivariable logistic regression model estimating the odds of being treated with DOACs, while adjusting for a number of pre-identified covariates to account for baseline differences at the time of cohort entry). Cox-proportional hazards regression models will be used to estimate adjusted hazards ratios (HRs) and corresponding 95% confidence intervals (CIs) for ischemic stroke or systemic embolization in the three cohorts. Meta-analyses of the site-specific results will be performed using random effects models. As secondary analyses, the composite outcome will be stratified by age (<85 and ≥85) and sex. In addition, an as treated analysis using inverse probability of censoring weights (IPCW) will be performed to account for non-random censoring. ;


Study Design


Related Conditions & MeSH terms


NCT number NCT03596502
Study type Observational
Source Canadian Network for Observational Drug Effect Studies, CNODES
Contact
Status Completed
Phase
Start date February 1, 2018
Completion date December 1, 2018

See also
  Status Clinical Trial Phase
Recruiting NCT05654272 - Development of CIRC Technologies
Completed NCT04571385 - A Study Evaluating the Efficacy and Safety of AP30663 for Cardioversion in Participants With Atrial Fibrillation (AF) Phase 2
Terminated NCT04115735 - His Bundle Recording From Subclavian Vein
Completed NCT05366803 - Women's Health Initiative Silent Atrial Fibrillation Recording Study N/A
Completed NCT02864758 - Benefit-Risk Of Arterial THrombotic prEvention With Rivaroxaban for Atrial Fibrillation in France
Recruiting NCT05442203 - Electrocardiogram-based Artificial Intelligence-assisted Detection of Heart Disease N/A
Completed NCT05599308 - Evaluation of Blood Pressure Monitor With AFib Screening Feature N/A
Completed NCT03790917 - Assessment of Adherence to New Oral anTicoagulants in Atrial Fibrillation patiEnts Within the Outpatient registrY
Enrolling by invitation NCT05890274 - Atrial Fibrillation (AF) and Electrocardiogram (EKG) Interpretation Project ECHO N/A
Recruiting NCT05316870 - Construction and Effect Evaluation of Anticoagulation Management Model in Atrial Fibrillation N/A
Recruiting NCT05266144 - Atrial Fibrillation Patients Treated With Catheter Ablation
Not yet recruiting NCT06023784 - The Impact of LBBAP vs RVP on the Incidence of New-onset Atrial Fibrillation in Patients With Atrioventricular Block N/A
Recruiting NCT05572814 - Transform: Teaching, Technology, and Teams N/A
Recruiting NCT04092985 - Smart Watch iECG for the Detection of Cardiac Arrhythmias
Completed NCT04087122 - Evaluate the Efficiency Impact of Conducting Active Temperature Management During Cardiac Cryoablation Procedures N/A
Completed NCT06283654 - Relieving the Emergency Department by Using a 1-lead ECG Device for Atrial Fibrillation Patients After Pulmonary Vein Isolation
Recruiting NCT05416086 - iCLAS™ Cryoablation System Post-Market Clinical Follow-up (PMCF) Study N/A
Completed NCT05067114 - Solutions for Atrial Fibrillation Edvocacy (SAFE)
Completed NCT04546763 - Study Watch AF Detection At Home
Completed NCT03761394 - Pulsewatch: Smartwatch Monitoring for Atrial Fibrillation After Stroke N/A