DOACs vs LMWHs in hospitalized medical patients: a systematic review and meta-analysis that informed 2018 ASH guidelines

Venous thromboembolism (VTE) is a relatively frequent complication in hospitalized patients, especially in those with risk factors. The benefit of using direct oral anticoagulants (DOACs) for prevention is controversial. This systematic review was performed as part of the American Society of Hematology (ASH) guidelines on VTE, developed in partnership with McMaster University. MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Epistemonikos were used as data sources from date of inception to November 2019. We included randomized trials in patients hospitalized for an acute medical disease, evaluating any DOACs vs other pharmacological prophylaxis, and included 3 trials with low risk of bias. We analyzed the effects of DOACs vs low-molecular-weight heparins (LMWHs) at 2 different time points: at the end of the short-term treatment phase (both drugs given for the same period of time) and at the end of the extended prophylaxis period (extended DOACs vs a shorter course of LMWHs). We observed that the use of DOACs did not reduce the risk of pulmonary embolism or symptomatic deep venous thrombosis (DVT) in comparison with LMWHs. However, the risk of major bleeding was slightly increased. Additionally, we observed that the benefit of DOACs previously reported was largely based on the reduction of asymptomatic DVT and was not apparent when only symptomatic events were considered. The use of DOACs in hospitalized medical patients slightly increases the risk of major bleeding with no appreciable benefit over LMWHs.