In this episode, I’ll discuss whether standard doses of apixaban are as effective as warfarin in severe obesity.
Initial studies for apixaban such as ARISTOTLE had a median weight of 82 kg and did not focus on determining efficacy in a severely obese patient population. Because of the lack of inclusion of patients with a BMI 40 and above in the initial approval studies for apixaban, many clinicians avoided use, and guidance statements by professional organizations even cautioned against use in this population.
Recently, several studies have e been published examining the effects of apixaban in obese patients, with the most recent one in Pharmacotherapy titled Multi-center retrospective study evaluating the efficacy and safety of apixaban versus warfarin for treatment of venous thromboembolism in patients with severe obesity.
In this multicenter retrospective study, just under 1100 severely obese patients with BMI 40 and above or weight 120 kg and above were analyzed. More patients received warfarin than apixaban by a factor of about 2.5:1. The mean weight and BMI were 137 kg and 46 kg/m2, respectively. The primary outcome looking at efficacy was time to recurrence of VTE within 12 months, and the primary outcome looking at safety was time to major bleeding within 12 months.
Patients who received apixaban had a significantly longer time to VTE recurrence than those who received warfarin, and this association remained significant even when potential confounders were controlled for using a Cox proportional hazards model. There were no significant differences between groups in mortality or bleeding measures.
Additionally, in a subgroup analysis of patients with a BMI >50 kg/m2 and/or weight >140 kg, there were no differences in efficacy or safety between apixaban and warfarin.
The study is retrospective in nature but it confirms existing evidence suggesting that apixaban is at least as effective, if not better than, warfarin in severely obese patients.
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