AHA 2018: Rivaroxaban, warfarin have similar risks of stroke and bleeding for obese AF patients

November 10, 2018 – Patients on rivaroxaban had significantly lower healthcare costs than patients who took warfarin.

New study results examining the comparative effectiveness, safety, and costs of rivaroxaban and warfarin among morbidly obese patients with non-valvular atrial fibrillation (NVAF) were presented Saturday at the 2018 American Heart Association (AHA) Scientific Sessions in Chicago.

Obesity and morbid obesity are associated with an increased risk of developing NVAF, which may be more severe and persistent this population. Anticoagulation is the standard of care for prevention of embolic events in patients with NVAF, with warfarin and direct-acting oral anticoagulants (DOACs) significantly reducing the risk of stroke in these patients. Because limited data exist regarding clinical outcomes of DOACs in patients with NVAF who are morbidly obese, care guidelines currently recommend against use of these therapies.

Although the study revealed that treatment with rivaroxaban and with warfarin resulted in similar risk, patients who took rivaroxaban, a DOAC, required significantly less total healthcare resource utilization and costs per patient per year, inclusive of medication costs, due to fewer inpatient and outpatient encounters than with patients on warfarin. Rivaroxaban has also been associated with reduced intracranial hemorrhage in NVAF patients when compared with warfarin.

The study used two large, geographically diverse, U.S. healthcare claims databases to examine health outcomes, resource utilization and costs for morbidly obese NVAF patients treated with rivaroxaban or warfarin from December 1, 2010 to December 31, 2016. A total of 267,467 adult patients met entry criteria, and 3,563 matched pairs of patients treated with rivaroxaban or warfarin were identified. Rivaroxaban and warfarin patients were 1:1 propensity score matched, helping reduce selection biases from measured confounders, such as comorbidities, and improving the internal validity of the estimates.

Rivaroxaban and warfarin had similar effectiveness (stroke: 1.4 percent versus 1.6 percent) and safety (major bleeding: 2.2 percent versus 2.7 percent), yet rivaroxaban was associated with lower total healthcare costs per patient per year than warfarin (total costs: $48,552 versus $52,418). This was primarily driven by lower hospitalization rate (50.2 percent versus 54.1 percent), shorter length of stay (7.5 versus 9.1 days), and less utilization of outpatient services (86 versus 115 encounters per patient per year). Routine monitoring of the anticoagulant effect of rivaroxaban is not recommended, contributing to this reduced use of outpatient services.

“This type of study is where comparative effectiveness research really shines,” said lead author and presenter Eric D. Peterson, MD, MPH, of the DCRI.

“We were able to gain real-world insights into outcomes and costs in this relatively rare patient population,” Peterson said. “Our findings extend the results of the ROCKET AF trial and add to the pharmacokinetic and pharmacologic data supporting the use of rivaroxaban in overweight and obese patients with NVAF without the need for routine monitoring. This will reassure clinicians that current dosing strategies are adequate and efficient in these populations.”

Janssen Scientific Affairs, LLC, funded this study.