Anticoagulant therapies and outcomes in obese patients with acute venous thromboembolism

Background: Direct oral anticoagulants (DOACs) are recommended in preference to traditional anticoagulants (LMWH ± warfarin) for treating acute venous thromboembolism (VTE). However, guidelines suggest avoiding DOACs in those >120 kg given limited data.

Objective: To capture outcome and prescription fill data in a cohort of patients >120 kg with acute VTE out to 1 year.

Methods: Using linked administrative data, a retrospective sub-study of obese patients (>120 kg) with acute VTE discharged from institutions from 2014 to 2017 was performed. Primarily, the overall rate of recurrent VTE was assessed. Secondarily, anticoagulant regimens (agent/dosing) and bleeding events were recorded with recurrent events confirmed by chart reviews. Outcomes were compared between DOACs and traditional therapies.

Results: Amongst 187 patients included, the overall rate of recurrent VTE out to 1 year was 0.006 events/patient year, and the only event during the entire follow-up occurred off therapy. Throughout the year, 38.5% were prescribed a DOAC only, 32.6% were prescribed traditional therapy only and 23.5% were switched from LMWH/warfarin to a DOAC. The proportion of patients receiving sub-therapeutic, standard or supra-therapeutic regimens were: DOAC (11.1%, 85.2%, 3.7%), LMWH (24.2%, 71.0%, 4.8%), warfarin (30.4%, 55.0%, 15.0%). Bleeding occurred in 9 (8.3%) and 9 (11.5%) patients on DOAC and traditional therapy, respectively (relative risk 0.85 [95%CI 0.44-1.28]).

Conclusions: More obese patients with acute VTE were prescribed DOACs than traditional therapies. Standard dosing was used for DOACs (85.2%), whereas sub-optimal dosing occurred for 25-33% receiving traditional therapies. Rates of recurrent VTE and bleeding were similar in the two groups, lending support for DOAC use in this population.