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DOAC Use in Obese Patients With Acute VTE
Study Questions:
Are direct oral anticoagulants (DOACs) safe and effective for use in obese patients with acute venous thromboembolism (VTE)?
Methods:
This was a retrospective matched cohort study of patients at the University of Pittsburgh Medical Center treated between January 1, 2011, and October 1, 2015. Patients 18 years of age and older with an admitting diagnosis of acute VTE were selected. Diagnosis of atrial fibrillation or atrial flutter were excluded. DOAC (apixaban, dabigatran, or rivaroxaban) or warfarin medication charge code from their index emergency department, observation, or hospital admission was also required for inclusion. Weight was collected during the index admission from the electronic health record. Patients with documented actual body weight of more than 100 kg and less than 300 kg were included.
The primary outcome was VTE recurrence within 12 months of index admission. Secondary outcome measures included pulmonary embolism (PE) and deep vein thrombosis (DVT), as separate events. Secondary outcomes also included bleeding events defined by any readmission within the 12-month period from index admission with a primary admission ICD-9-CM or ICD-10-CM code for bleeding.
Results:
Of 2,102 patients receiving a DOAC for an acute VTE admission, 632 patients met the criterion for weight greater than 100 kg but less than 300 kg. Of DOACs used, rivaroxaban had highest use (580 patients [91.8%]), then apixaban (33 patients [5.2%]), and lastly dabigatran (19 patients [3%]). In the warfarin group, 1,208 patients met the same weight definition. Baseline characteristics were similar between groups except cancer rates, which were higher in the DOAC group (n = 45 [7.1%] DOACs; n = 40 [3.3%] warfarin; p < 0.0001). About 20% of patients in each group had a history of VTE. Median weight was about 115 kg, ranging from 101 to 299 kg. The DOAC group had 264 (41.8%) patients over 120 kg, and the warfarin group had 497 (41.1%). Body mass index (BMI) data for the DOAC group were available for 420 patients, of which 183 (43.6%) had BMI >40. BMI data were available for 755 patients in the warfarin group, of which 342 (45.3%) had BMI >40.
The primary outcome of VTE recurrence within 12 months occurred in 41 (6.5%) patients in the DOAC group compared with 77 (6.4%) patients in the warfarin group (p = 0.93). PE occurred in 3.7% of the DOAC group and 3.8% of the warfarin group (p = 0.94). Occurrence of DVT was 3% and 3.5% in the DOAC and warfarin groups, respectively (p = 0.56). There was no significant difference in risk of recurrent VTE found between patients treated with DOAC versus warfarin (hazard ratio 1.03; 95% confidence interval, 0.71-1.50). Within 12 months of the index event, bleeding occurred in 11 (1.7%) DOAC patients and 14 (1.2%) warfarin patients (p = 0.31). The most common types of bleeding in both groups were gastrointestinal and genitourinary.
Conclusions:
In obese patients with acute VTE, no differences were observed in recurrence of VTE, PE, or DVT within 12 months of the index admission between treatment with DOACs and warfarin. There were also no significant differences found in bleeding between the DOAC and warfarin groups.
Perspective:
This retrospective study adds important information about the use of DOACs in obese patients with acute VTE. Due to the study’s retrospective nature, limitations include lack of information regarding adherence and lack of follow-up international normalized ratios or time in therapeutic range for warfarin-treated patients. Of note, rivaroxaban was the primary DOAC used in the study (91.8%); therefore, results may not be representative of other DOACs.
Clinical Topics: Anticoagulation Management, Pulmonary Hypertension and Venous Thromboembolism, Vascular Medicine, Anticoagulation Management and Venothromboembolism
Keywords: Anticoagulants, Venous Thromboembolism, Venous Thrombosis, Warfarin, Obesity, Body Mass Index, Pulmonary Embolism, Patient Readmission
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