Rivaroxaban
The US Food and Drug Administration’s (FDA) Mini-Sentinel surveillance system has revealed no new safety concerns associated with rivaroxaban use in patients with nonvalvular atrial fibrillation.
Results from this surveillance showed the risk of ischemic stroke was lower in patients who received rivaroxaban than in those who received warfarin.
Rivaroxaban was also associated with a lower risk of intracranial hemorrhage but a higher risk of gastrointestinal bleeding compared to warfarin.
These findings were published in Pharmacoepidemiology & Drug Safety.
About the surveillance
The FDA’s Sentinel Initiative began in 2008 as a multi-year effort to create a national electronic system for monitoring the safety of approved and FDA-regulated medical products using existing electronic healthcare data from multiple sources.
The initiative is the FDA’s response to the Food and Drug Administration Amendments Act (FDAAA), and it includes Mini-Sentinel, a working pilot project to develop an active surveillance system and complement existing methods of safety surveillance.
Rivaroxaban results
Researchers analyzed Mini-Sentinel data for patients with nonvalvular atrial fibrillation who initiated treatment with rivaroxaban or warfarin from November 2011 to April 2015.
To examine the safety of both products, methodologies included assessing ICD-9-CM codes from inpatient claims and evaluating rates of gastrointestinal bleeding, ischemic stroke, and intracranial hemorrhage.*
The incidence of ischemic stroke was higher among patients on warfarin (268/80,180) than among those on rivaroxaban (82/36,512). The adjusted incidence rate per 1000 person-years was 9.57 among rivaroxaban users and 17.10 among warfarin users. The adjusted hazard ratio was 0.61 (95% CI, 0.47-0.79).
The incidence of gastrointestinal bleeding was higher among patients on rivaroxaban (423/36,173) than among those on warfarin (651/79,520). The incidence rate was 50.20 among rivaroxaban users and 34.82 among warfarin users. The hazard ratio was 1.47 (95% CI, 1.29-1.67).
The incidence of intracranial hemorrhage was higher among patients on warfarin (143/79,529) than among those on rivaroxaban (46/36,171).The incidence rate was 5.41 among rivaroxaban users and 7.49 among warfarin users. The hazard ratio was 0.71 (95% CI, 0.50-1.01).
*Total patient numbers differed in the analyses for each endpoint. For example, there were 80,180 warfarin users in the ischemic stroke analysis and 79,520 warfarin users in the analysis of gastrointestinal bleeding.