Evaluating the effect of morbid obesity on DVT in patients already on doac therapy: A retrospective analysis

Abstract Background Direct oral anticoagulants (DOACs) are widely used for managing venous thromboembolism (VTE) and atrial fibrillation (AFib) due to their convenience and efficacy. However, their effectiveness in patients with extreme obesity (BMI > 40 kg/m² or weight > 120 kg) is uncertain, as obesity significantly alters drug absorption, distribution, and clearance. This population faces higher risks of VTE recurrence, with limited data to guide optimal DOAC dosing (1-3). Despite their fixed-dose design, DOACs may fail to achieve therapeutic levels in severe obesity, potentially compromising safety and efficacy (3). Guidelines from the International Society on Thrombosis and Hemostasis (ISTH) and the FDA advise caution, often recommending warfarin for this group (4-5). This study aims to assess the real-world outcomes of DOACs in obese patients with VTE, addressing the gap in knowledge on DOAC safety for individuals with high BMIs, to guide future treatment strategies in this high-risk group. Methods We conducted a retrospective cohort study of 1,562 patients diagnosed with VTE and were already on DOACs. Patients were stratified by obesity status, defined as a body mass index (BMI) > 40. Logistic regression was used to evaluate the association between obesity and both bleeding events and mortality, while negative binomial regression assessed predictors of hospital length of stay. Covariates included age, sex, race, insurance status, and comorbidities such as diabetes, chronic kidney disease, and hypercoagulable states. Results Of the 1,562 patients, 13.0% were classified as obese. Obesity was not significantly associated with bleeding events (OR = 1.404, 95% CI: 0.781–2.526, p = 0.2572) or mortality (OR = 0.879, 95% CI: 0.424–1.825, p = 0.7299). Similarly, obesity did not significantly influence hospital length of stay (IRR = 1.037, 95% CI: 0.880–1.223, p = 0.6616). Significant predictors of mortality included older age, male sex, and hypercoagulable state, while male sex, diabetes, and insurance status were associated with longer hospital stays. Discussion In this cohort of patients with VTE receiving DOAC therapy, obesity (BMI > 40) was not associated with increased risk of DVT-related complications, bleeding, or mortality. These findings support the safety and efficacy of DOACs in obese patients and suggest that BMI alone should not be a limiting factor in their use. Further prospective studies are needed to confirm these observations and inform clinical guidelines. Conclusion Obesity was not significantly associated with adverse outcomes in patients with VTE treated with DOACs. These results support the continued use of DOACs in obese individuals and highlight the need for further research to guide anticoagulation strategies in this population. Disclaimer This research was supported in whole or in part by HCA Healthcare and/or an HCA Healthcare affiliated entity. The views expressed in this publication represent those of the authors and do not necessarily represent the official views of HCA Healthcare or any of its affiliated entities.