Safety and efficacy of direct oral anticoagulants across body mass index groups in patients with venous thromboembolism: a retrospective cohort design

Current literature on the safety and efficacy of direct oral anticoagulants (DOACs) in patients of extreme weights are limited, however, they are still being prescribed in these populations. The objective of this study is to describe the safety and efficacy of DOAC therapy in patients of extreme weights for the treatment of venous thromboembolism (VTE) using body mass index (BMI) groups. A multi-site, retrospective cohort design at four hospitals was performed. Patients who experienced an initial VTE between November 2012 and August 2017 and placed on a DOAC were included. Patients were defined as: extremely obese (EO) if BMI ≥ 40 kg/m2, obese if BMI 30-39.9 kg/m2, normal/overweight if BMI 18.5-29.9 kg/m2, and underweight if BMI < 18.5 kg/m2. The primary efficacy outcome of recurrent VTE and primary safety outcome of major bleeding (MB) within 12 months were compared between weights. Univariate statistical tests and multivariate logistic regression analyses were performed. Rates of recurrent VTE showed no significant differences (p = 0.58) across groups; 7.8% (11/142) EO, 4.7% (18/383) obese, 5.2% (27/517) normal/overweight, and 5.9% (1/17) underweight. Proportions of MB were overall significantly different (p = 0.026); 6.3% (9/142) EO, 10.4% (40/383) obese, 10.1% (52/517) normal/overweight, and 29.4% (5/17) underweight. EO and obese patients had similar odds of MB compared to normal/overweight (OR 0.61, 95% CI [0.29, 1.26] and OR 1.04, 95% CI [0.67, 1.61]). Underweight patients showed larger odds of MB compared to normal/overweight (OR 3.73, 95% CI [1.26, 11.0]). This study found that recurrence of VTE was not associated with BMI. However, the proportions of major bleeding were statistically different among the BMI categories.