Introduction
Although guideline-adherent antithrombotic therapy (ATT) for stroke prevention in atrial fibrillation (AF) is associated with lower mortality and thromboembolism, ATT uptake shows geographic variation worldwide. We aimed to assess thromboembolic risk and baseline ATT by geographic region and identify factors associated with prescription of ATT in a large, truly global registry of patients with recently diagnosed AF.
Methods and Results
Our analysis comprises 15,092 patients newly diagnosed with non-valvular AF at risk for stroke, enrolled in Phase II of Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF). Global oral anticoagulation (OAC) use was 79.9%, being highest in Europe (90.1%), followed by Africa/Middle East (87.4%) and Latin America (85.3%), North America (78.3%) and Asia (55.2%). Among OAC users, vitamin K antagonists (VKAs) have been replaced by non-VKA OACs (NOACs) as the more prevalent OAC option in all regions, with highest use in North America (66.5%) and lowest in Asia (50.2%). In Asia, OAC was 80.4% in community hospitals but only 49.8% in university hospitals and 42.6% in specialist offices, and varied from 21.0% in China to 89.7% in Japan (NOACs at 5.8% in China and 83.3% in Japan). Globally, 76.5% of low-risk patients were prescribed ATT (46.1% OAC), whereas 17.7% high-risk patients were not anticoagulated (Europe 8.8%; North America 18.9%; Asia 42.4%).
Conclusion
Substantial inter- and intra-regional differences in ATT for stroke prevention in AF are evident in this global registry. While guideline-adherent ATT can be further improved, NOACs are the main contributor to high OAC use worldwide.
Probability of treatment persistence with dabigatran after 2 years was approximately 70%. Nearly one-half of the patients who stopped dabigatran switched to another oral anticoagulant agent. Patients from North America, and those with paroxysmal, persistent, or symptomatic AF, may be at a higher risk for discontinuing dabigatran.
The study was designed under the clinical expert guidance of an executive steering committee composed of representatives from the international academic scientific and medical communities, as well as from the Sponsor Company. Members from the Sponsor Company did not have voting privileges. Data were collected independently by participating clinical sites on a secure webbased server and the Sponsor was not involved in data collection. Analysis was performed by the Sponsor who contributed to writing the report and in the decision to submit the manuscript for publication. This work is intended to form part of the requirements to fulfill a PhD thesis for author MP. See page 390 for disclosure information.
Background
Prospectively collected, routine clinical practice-based data on antithrombotic therapy in non-valvular atrial fibrillation (AF) patients are important for assessing real-world comparative outcomes. The objective was to compare the safety and effectiveness of dabigatran versus vitamin K antagonists (VKAs) in patients with newly diagnosed AF.
Methods and results
GLORIA-AF is a large, prospective, global registry program. Consecutive patients with newly diagnosed AF and CHA2DS2-VASc scores ≥ 1 were included and followed for 3 years. To control for differences in patient characteristics, the comparative analysis for dabigatran versus VKA was performed on a propensity score (PS)-matched patient set. Missing data were multiply imputed. Proportional-hazards regression was used to estimate hazard ratios (HRs) for outcomes of interest. Between 2014 and 2016, 21,300 eligible patients were included worldwide: 3839 patients were prescribed dabigatran and 4836 VKA with a median age of 71.0 and 72.0 years, respectively; > 85% in each group had a CHA2DS2-VASc-score ≥ 2. The PS-matched comparative analysis for dabigatran and VKA included on average 3326 pairs of matched initiators. For dabigatran versus VKAs, adjusted HRs (95% confidence intervals) were: stroke 0.89 (0.59–1.34), major bleeding 0.61 (0.42–0.88), all-cause death 0.78 (0.63–0.97), and myocardial infarction 0.89 (0.53–1.48). Further analyses stratified by PS and region provided similar results.
Conclusions
Dabigatran was associated with a 39% reduced risk of major bleeding and 22% reduced risk for all-cause death compared with VKA. Stroke and myocardial infarction risks were similar, confirming a more favorable benefit-risk profile for dabigatran compared with VKA in clinical practice.
Clinical trial registrationhttps://www.clinicaltrials.gov. NCT01468701, NCT01671007.
Graphical abstract
• This study shows that in non-valvular AF patient population, with up to 2 years of follow-up, the use of dabigatran led to a low incidence of ischemic stroke, major bleeding, and myocardial infarction in routine clinical care, confirming the sustained safety and effectiveness of dabigatran in clinical practice over 2 years of follow-up.
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