Direct oral anticoagulants (DOACs) are often used in patients with atrial fibrillation or flutter instead of warfarin and although supporting evidence is limited, available studies suggest this may be an acceptable route of care. Our study assessed the question: are DOACs as effective and safe as warfarin in patients with atrial fibrillation and class III obesity specifically in a rural population?
A retrospective analysis was conducted by examining the first 6-12 months of therapy with a DOAC (apixaban or rivaroxaban) or warfarin in patients with weight >120kg or class III obesity. Events of interest, thrombosis and bleeding, were documented for analysis. The risk and odds of events of interest for both groups were calculated and compared.
Characteristics of both arms were similar (DOAC n=42; warfarin n=43). A lack of thrombosis events limited efficacy analysis. A total of 22 bleeds occurred with 8 in patients prescribed a DOAC (7 minor; 1 major) and 14 in those prescribed warfarin (12 minor; 2 major). Weight in kg (p<0.001), BMI (p=0.013) and HAS-BLED score (p=0.035) were predictive of a first bleeding event in patients prescribed warfarin. The odds ratio for any type of bleed on DOAC vs warfarin was 0.55 (0.180-1.681; 95% CI).
In patients with atrial fibrillation and class III obesity, regarding safety, DOACs appear to be non-inferior to warfarin during the first six to 12 months of therapy in our rural population – consistent with other analyses; however, the lack of thrombosis events limited the efficacy analysis.
Individuals with obesity, defined as body mass index (BMI) greater than 30kg/m 2 ,
are at an increased risk for atrial fibrillation, an irregular heart rhythm that can lead to cardioembolic stroke. Guideline directed medical therapy for the prevention of thromboembolic (TE) events such as stroke in patients with atrial fibrillation or flutter remains anticoagulation. Warfarin remains one of the most widely prescribed anticoagulants for patients with atrial fibrillation but comes with a number of challenges including the need for regular international normalized ratio (INR) testing to ensure levels fall within the therapeutic range. Direct oral anticoagulants (DOACs), such as the factor Xa inhibitors (i.e. apixaban and rivaroxaban), are relatively new medications that have become attractive alternatives to warfarin as they have fewer monitoring and follow-up requirements, a more rapid on-set and off-set, and fewer medication and dietary interactions. Despite these advantages, data on factor Xa inhibitors’ efficacy and safety in individuals with atrial fibrillation and concurrent obesity are limited and in some cases, such as in patients with class III obesity (BMI greater than 40kg/m 2 ), guidelines advise against their use. Despite this limitation, studies evaluating warfarin in individuals with obesity have illustrated it can be used safely and effectively although higher doses and additional monitoring may be required. , For the DOACs, only half of the large phase 3 approval studies investigated the medications’ safety and efficacy by weight categories. In a review of available studies, it was determined that data were of insufficient quality while evidence of venous TE event prevention was lacking compared to stroke prevention in the subgroup of patients with Class 3 obesity treated with DOAC therapy. Finally, DOAC medication use has been found to be lower amongst rural Medicare beneficiaries compared to their urban counterparts. While the described advantages of DOACs warrant their use in all areas of the country, rural areas are most commonly associated with higher rates of obesity,
which could at least partially explain hesitancy on their use in these regions.
Given the current, growing incidence of atrial fibrillation and trends in obesity for the US, more studies are needed to verify the efficacy and safety of DOAC medications compared to warfarin and particularly in rural populations.
, The current study was designed to evaluate the question: In atrial fibrillation patients with concurrent class III obesity, is DOAC anticoagulation, specifically apixaban and rivaroxaban, as effective and safe in terms of TE and bleeding events, respectively, as warfarin anticoagulation during the first 6-12 months of therapy in a rural community?