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Low-dose rivaroxaban confers similar risks vs. standard dose in Asian AF population
Asian patients with atrial fibrillation who were treated with low-dose rivaroxaban had similar risks for bleeding and thromboembolism compared with those treated with a standard dose of rivaroxaban, according to a study published in the Journal of the American College of Cardiology.
The only difference was that the low dose of rivaroxaban was associated with higher risk for MI vs. the standard dose, researchers reported.
AF and rivaroxaban
Yi-Cheng Lin, PharmD, of the department of pharmacy at Taipei Medical University Hospital in Taiwan, and colleagues analyzed data from 6,558 patients from Taiwan with AF or atrial flutter from May 2014 to September 2015. During this period, patients filled prescriptions for either low-dose (n = 2,373) or standard-dose (n = 4,185) rivaroxaban (Xarelto, Janssen). Low-dose rivaroxaban was defined as 10 mg per day, whereas standard-dose rivaroxaban was defined as 15 mg per day or 20 mg per day.
Patients were excluded if they filled a prescription for rivaroxaban before the study period, were younger than 20 years, filled a prescription once during the study period, had their prescription filled by a department other than cardiology or neurology and were diagnosed with deep vein thrombosis, pulmonary embolism or end-stage renal disease.
Other information analyzed included baseline bleeding risk and thromboembolic risk and medication adherence.
The primary safety outcomes were hospitalization or major bleeding or clinically relevant nonmajor bleeding. Primary efficacy outcomes were thromboembolic events, which included ischemic stroke, MI and systemic embolism.
Patients treated with low-dose rivaroxaban had a significantly higher risk for MI compared with those treated with standard-dose rivaroxaban (subdistribution HR = 2.26; 95% CI, 1.13-4.52). The low-dose group had a trend toward increased risk for systemic embolism vs. the standard-dose group (subdistribution HR = 2.04; 95% CI, 0.95-4.36).
Similar risks
Both groups had similar risks for ischemic stroke (subdistribution HR = 0.89; 95% CI, 0.63-1.27), nonmajor clinically relevant bleeding (subdistribution HR = 0.93; 95% CI, 0.81-1.07) and major bleeding (subdistribution HR = 1.16; 95% CI, 0.82-1.63).
“To our knowledge, this was the first population-based study to examine the effectiveness and safety of standard- and low-dose rivaroxaban in Asians with AF,” Lin and colleagues wrote. “No prior studies compared different doses of rivaroxaban directly in an Asian population.”
In a related editorial, Peter Brønnum Nielsen, MSc, PhD, of the Aalborg Thrombosis Research Unit at Aalborg University in Denmark and the department of cardiology at Aalborg University Hospital, and colleagues wrote: “The data does provide clinical insights. Perhaps the most accurate interpretation of the results is that the routine practice for choosing the optimal dosage of rivaroxaban has been safe in this patient population, and that rivaroxaban has an acceptable safety profile and effectively reduces stroke risk. We encourage additional comparative effectiveness research that may contribute to the totality of evidence on the use of optimal [direct oral anticoagulant] dosing in AF patients with different ethnical origin.” – by Darlene Dobkowski
Disclosures: The authors report no relevant financial disclosures. Nielsen reports he received personal fees from Bayer, Boehringer Ingelheim and Bristol-Myers Squibb/Pfizer and grant support from Bristol-Myers Squibb/Pfizer. Please see the editorial for all other authors’ relevant financial disclosures.