Efficacy and Safety of Direct Oral Anticoagulants in Venous Thromboembolism Compared to Traditional Anticoagulants in Morbidly Obese Patients: A Systematic Review and Meta-Analysis

Background Randomized clinical trials comparing the efficacy and safety of direct oral anticoagulants (DOAC) with vitamin K antagonist (VKA) or low molecular weight heparin (LMWH) for the treatment of venous thromboembolism (VTE) generally exclude patients who are morbidly obese (body mass index ≥ 40 kg/m(2) or weight ≥ 120 kg). Recently, smaller studies have compared DOACs with warfarin or low molecular weight heparin (LMWH) in morbidly obese patients with VTE. We aim to systematically review and do a meta-analysis of the studies that directly compared DOACs with VKAs or LMWH in morbidly obese patients. Methods Studies comparing DOAC with warfarin or LMWH in patients with acute VTE were identified through electronic literature searches of MEDLINE, EMBASE, Scopus, clinicaltrials.gov, and the Cochrane Library up to March 2020. The primary efficacy outcome was recurrent VTE and the primary safety outcome was major bleeding as defined by the International Society on Thrombosis and Haemostasis (ISTH) guidelines. Study-specific odds ratios (OR) were calculated and combined using a random-effects model meta-analysis. Result Five studies were identified. Recurrent VTE occurred in 95 of 3207 (2.96%) patients in the DOAC group and 81 of 3181 (2.54%) patients in the VKA and LMWH group (OR: 1.17; 95% CI 0.87 to 1.59, p=.30). Major bleeding occurred in 63 of 3316 (1.89%) patients in the DOAC group, and 83 of 3259(2.54%) patients in the VKA or LMWH group (OR: 0.74; 95% CI: 0.53 to 1.03, p=.08). Sensitivity analysis comparing factor Xa inhibitors apixaban and rivaroxaban to warfarin also yielded consistent findings. Conclusion DOACs showed similar efficacy and safety in the prevention of recurrent VTE risk and major bleeding events in morbidly obese patients when compared to warfarin/LMWH. Our study underscores the need for further modifications of therapy to reduce the high VTE recurrence rate irrespective of whether the patient is on a DOAC or VKA. This might be possible through a very large multi-institutional randomized clinical trial.