Alexander G. G. Turpie

The management of atrial fibrillation (AF), the most common sustained arrhythmia, impacts healthcare resource utilization (HCRU). This study aims to estimate global resource use in AF patients, using the GARFIELD-AF registry. A prospective cohort study was conducted to characterize HCRU in AF patients enrolled in sequential cohorts from 2012 to 2016 in 35 countries. Components of HCRU studied were hospital admissions, outpatient care visits, and diagnostic and interventional procedures occurring during follow-up. AF-related HCRU was reported as the percentage of patients demonstrating at least one event and was quantified as rate-per-patient-per-year (PPPY) over time. A total of 49,574 patients was analyzed, having an overall median follow-up of 719 days. Almost all patients (99.5%) had at least one outpatient care visit, while hospital admissions were the second most frequent medical contact, with similar proportions in North America (37.5%) and Europe (37.2%), and slightly higher in the other GARFIELD-AF countries (42.0%; namely Australia, Egypt, and South Africa). Asia and Latin America showed lower percentages of hospitalizations, outpatient care visits, and diagnostic and interventional procedures. Analyses of GARFIELD-AF highlighted the vast AF-related HCRU, underlying significant geographical differences in the type, quantity, and frequency of AF-related HCRU. These differences were likely attributable to health service availability and differing models of care.

Real-world data on non-vitamin K oral anticoagulants (NOACs) are essential in determining whether evidence from randomised controlled clinical trials translate into meaningful clinical benefits for patients in everyday practice. RIVER (RIVaroxaban Evaluation in Real life setting) is an ongoing international, prospective registry of patients with newly diagnosed non-valvular atrial fibrillation (NVAF) and at least one investigator-determined risk factor for stroke who received rivaroxaban as an initial treatment for the prevention of thromboembolic stroke. The aim of this paper is to describe the design of the RIVER registry and baseline characteristics of patients with newly diagnosed NVAF who received rivaroxaban as an initial treatment. Between January 2014 and June 2017, RIVER investigators recruited 5072 patients at 309 centres in 17 countries. The aim was to enroll consecutive patients at sites where rivaroxaban was already routinely prescribed for stroke prevention. Each patient is being followed up prospectively for a minimum of 2-years. The registry will capture data on the rate and nature of all thromboembolic events (stroke / systemic embolism), bleeding complications, all-cause mortality and other major cardiovascular events as they occur. Data quality is assured through a combination of remote electronic monitoring and onsite monitoring (including source data verification in 10% of cases). Patients were mostly enrolled by cardiologists (n = 3776, 74.6%), by internal medicine specialists 14.2% (n = 718) and by primary care/general practice physicians 8.2% (n = 417). The mean (SD) age of the population was 69.5 (11.0) years, 44.3% were women. Mean (SD) CHADS2 score was 1.9 (1.2) and CHA2DS2-VASc scores was 3.2 (1.6). Almost all patients (98.5%) were prescribed with once daily dose of rivaroxaban, most commonly 20 mg (76.5%) and 15 mg (20.0%) as their initial treatment; 17.9% of patients received concomitant antiplatelet therapy. Most patients enrolled in RIVER met the recommended threshold for AC therapy (86.6% for 2012 ESC Guidelines, and 79.8% of patients according to 2016 ESC Guidelines). The RIVER prospective registry will expand our knowledge of how rivaroxaban is prescribed in everyday practice and whether evidence from clinical trials can be translated to the broader cross-section of patients in the real world. Unique identifier: NCT02444221 . Registerd 14 May 2015; Retrospectively Registered.

The prospective, observational XANTUS study demonstrated low rates of stroke and major bleeding in real-world rivaroxaban-treated patients with non-valvular atrial fibrillation (NVAF) from Western Europe, Canada and Israel. XANTUS-EL is a component of the overall XANTUS programme and enrolled patients with NVAF treated with rivaroxaban from Eastern Europe, the Middle East and Africa (EEMEA) and Latin America. Patients with NVAF starting rivaroxaban for stroke prevention were consecutively recruited and followed for 1 year, at approximately 3-month intervals, or for ≥30 days after permanent rivaroxaban discontinuation. Primary outcomes were major bleeding, adverse events (AEs), serious AEs and all-cause mortality. Secondary outcomes included stroke, non-central nervous system systemic embolism (non-CNS SE), transient ischaemic attack (TIA), myocardial infarction (MI) and non-major bleeding. All major outcomes were centrally adjudicated. Overall, 2064 patients were enrolled; mean age ± standard deviation was 67.1 ± 11.32 years; 49.3% were male. Co-morbidities included heart failure (30.9%), hypertension (84.2%), diabetes mellitus (26.5%), prior stroke/non-CNS SE/TIA (16.2%) and prior MI (10.7%). Mean CHADS2, CHA2DS2-VASc and HAS-BLED scores were 2.0, 3.6 and 1.6, respectively. Treatment-emergent event rates were (events/100 patient-years, [95% confidence interval]): major bleeding 0.9 (0.5-1.4); all-cause mortality 1.7 (1.2-2.4); stroke/non-CNS SE 0.7 (0.4-1.2); any AE 18.1 (16.2-20.1) and any serious AE 8.3 (7.0-9.7). One-year treatment persistence was 81.9%. XANTUS-EL confirmed low stroke and major bleeding rates in patients with NVAF from EEMEA and Latin America. The population was younger but with more heart failure and hypertension than XANTUS; stroke/SE rate was similar but major bleeding lower.

Background: Rivaroxaban is a novel oral anticoagulant indicated for prophylaxis against deep vein thrombosis and pulmonary embolism in patients undergoing total hip replacement (THR) or total knee replacement (TKR) surgery. Objective: To evaluate major bleeding (MB) in THR/TKR patients receiving post-operative rivaroxaban. Methods: Electronic medical records of nearly 10 million US Department of Defense (DoD) beneficiaries were queried from 1 January 2013 through 30 June 2015. Using the validated Cunningham case-finding algorithm, post-surgical MB events in rivaroxaban users were identified and analyzed. The incidence of MB was determined, and descriptive statistics were used to compare patient characteristics and other covariates in those with and without MB. Two additional methods were used to explore and identify bleeding cases that were not considered MB events per the study case-finding algorithm. Results: A total of 12,429 patients received THR and/or TKR surgery, and were post-operatively prescribed rivaroxaban. Nine patients had MB, yielding an incidence proportion of 0.07% (95% CI 0.02–0.13). The alternative case-finding methods found bleeding incidences of 0.46% and 0.21%, though it is not clear whether these are clinical MB cases, since the alternative methods were not validated. Conclusions: The incidence of MB in this retrospective analysis is lower than that observed in the clinical trials of rivaroxaban. Whether this is due to lower real-world MB rates or challenges with case-finding algorithms is unclear.

The nonvitamin K antagonist oral anticoagulants (NOACs), also referred to as direct oral anticoagulants (DOACs), dabigatran, apixaban, edoxaban, and rivaroxaban, have emerged as effective alternatives to vitamin K antagonists (VKAs) across several indications, including the prevention of stroke and systemic embolism (SSE) in patients with atrial fibrillation (AF) and the treatment of venous thromboembolism (VTE). Their use in patients with renal impairment is of particular importance, given the prevalence of renal dysfunction in the indicated populations and the impact of renal function on the metabolism of the NOACs. This publication reviews the pharmacokinetic/pharmacodynamic properties of the NOACs and clinical trial results for patients with renal impairment within the AF and VTE indications. Pharmacokinetic/pharmacodynamic data show the NOACs are dependent on renal clearance to varying extents. Relative to VKAs, the efficacy and safety of the NOACs is preserved in patients with moderate renal impairment. The dosing recommendations for patients with renal impairment differ depending on the NOAC, whereby some of the NOACs require dose reductions based solely on renal function, while others require consideration of additional criteria. However, despite these specific dosing recommendations, emerging real-world evidence suggests patients are not being dosed appropriately, indicating a possible knowledge gap. Adherence to recommended dosing algorithms has implications on the optimal efficacy and safety of the NOACs. To this end, renal function should be assessed in patients on a NOAC, as worsening of renal function may warrant change in the dose of a NOAC or change in oral anticoagulant.

Data from post-authorization studies and registries are valuable in establishing the safety and effectiveness of therapies in real-life settings, particularly as physicians may have concerns about the robustness of safety data from randomized controlled trials (RCTs). Furthermore, in routine clinical practice, there may be a potential for increased adverse event reporting with new therapies, and their true safety profile may be difficult to elucidate. The non-vitamin K antagonist (VKA) oral anticoagulant (NOAC) rivaroxaban is a direct factor Xa inhibitor, first approved for the prevention of venous thromboembolism (VTE) following elective hip or knee replacement surgery in 2008, and now licensed for use in five indications in Europe in the venous and arterial thromboembolic space. A number of Phase IV, non-interventional studies, and independent registries are completed or underway that aim to further evaluate safety outcomes with rivaroxaban in everyday clinical practice. These include XAMOS (XArelto in the prophylaxis of post-surgical venous thromboembolism after elective Major Orthopaedic Surgery of the hip or knee), XANTUS (XArelto on preveNtion of sTroke and non-central nervoUS system systemic emboilism in patients with non-valvular atrial fibrillation), and XALIA (XArelto for Long-term and Initial Anticoagulation in venous thromboembolism). Results to date—from XAMOS—show that rivaroxaban has an acceptable safety profile in real-life, with outcomes that are in line with the RECORD (REgulation of Coagulation in ORthopedic surgery to prevent Deep vein thrombosis and pulmonary embolism) clinical trial programme. International and national registries are also gathering information on rivaroxaban and other NOACs. Together, this breadth of studies illustrates an ongoing commitment to understanding real-life outcomes with NOACs.