Data from Antithrombosis News - Curated by EPG Health - Last updated 28 August 2018
The first study discussion in today’s late breaking registry results session was, Comparative effectiveness of oral anticoagulants in everyday practice. Researchers compared baseline characteristics and comparative safety and effectiveness of oral anticoagulants (OACs) vs no anticoagulant and NOACs vs VKAs in patients with newly diagnosed AF with a CHADSVASC of >/=2. Safety was evaluated using major bleed events and effectiveness with all-cause mortality and stroke, over a 2 year follow up.
The study included 26,742 patients from the Global Anticoagulant Registry in the FIELD–Atrial Fibrillation (GARFIELD-AF); an ongoing, observational, worldwide study of adults with newly diagnosed NVAF.
This study used cox proportional hazards models for propensity score weighting for treatment defined as the first treatment after index diagnosis. Whilst this was a prospective observational registry study, multiple factors were accounted for when considering potential confounders, including demographics, medical history and other baseline features.
Results demonstrated that those given no treatment compared with those with any type of OAC had a significantly worse all-cause mortality (HR 0.83, p<0.001) and incidence of stroke (HR 0.73, p=0.003), but no significant difference for major bleeding (HR 1.36, p=0.053) when adjusted for all the identified confounders. NOACs were superior to VKA with respect to all-cause mortality only (HR 0.81, p=0.001), and not significantly different for incidence of stroke and major bleed.
The difference in all-cause mortality without any treatment was commented on by Professor John Camm, questioning whether patients not given treatment are actually receiving suboptimal treatment in the real world. It was responded that the GARFIELD-AF study group are looking into this.
The second study discussion, Adverse one-year outcomes for patients newly treated with oral anticoagulants plus antiplatelet therapy after diagnosis of atrial fibrillation looked to determine the baseline characteristics and comparative safety of OAC + antiplatelet vs OAC alone in patients with newly diagnosed AF and >/= 1 risk factor for stroke.
The primary endpoints were all-cause mortality, stroke, major bleeding and MI/ACS at 1 year. Again, this was adjusted for multiple covariates, totalling 40. This was important as baseline characteristics of the OAC + AP group had a very different (inferior) cardiovascular risk profile compared with the OAC group. After adjustment for these covariates (in both populations with and without pre-existing coronary artery disease and peripheral artery disease), all-cause mortality and stroke risk was higher in the OAC + AP group vs the OAC group.
This suggests those who receive OAC + AP at the time of diagnosis have a worse prognosis than patients receiving OAC alone, challenging the use of combined OAC + AP therapy among those without a clear indication for AP therapy.