The quality of evidence is downgraded by study limitations (unclear allocation concealment and lack of blinding).
A Cochrane review [Abstract] 1 included 16 studies with a total of 5 167 subjects with cancer and with venous thromboembolism (VTE).
Low molecular weight heparins (LMWHs) versus vitamin K antagonists (VKAs):There were no differences in mortality up to 12 months of follow-up (RR 1.00, 95% CI 0.88 to 1.13; 5 studies, n=1 747), in major bleeding (RR 1.09, 95% CI 0.55 to 2.12; 4 studies, n=1 712), minor bleeding (RR 0.78, 95% CI 0.47 to 1.27; 4 studies, n=1 712; statistical heterogeneity I2 =78%), or thrombocytopenia (RR 0.94, 95% CI 0.52 to 1.69; 1 study, n=138) between LMWHs and VKAs. LMWHs reduced the recurrence of VTE compared to VKAs (RR 0.58, 95% CI 0.43 to 0.77; 5 studies, n=1 781).Direct oral anticoagulants (DOACs) versus VKAs:There were no differences in mortality (RR 0.93, 95% CI 0.71 to 1.21; 4 studies, n=1 031), recurrent VTE (RR 0.66, 95% CI 0.33 to 1.31; 4 studies, n=1 022), major bleeding (RR 0.77, 95% CI 0.38 to 1.57; 4 studies, n=1 030), or minor bleeding (RR 0.84, 95% CI 0.58 to 1.22; 4 studies, n=1 030). DOACs versus LMWH:One study found no difference in mortality up to 12 months of follow-up (RR 1.07, 95% CI 0.92 to 1.25; 1 study, n=1 016), but there was a likely reduction with DOACs in VTE recurrence up to 12 months of follow-up (RR 0.69, 95% CI 0.47 to 1.01; 1 study, n=1 016) compared to LMWHs. DOAC increased major bleeding at 12 months of follow-up compared to LMWH (RR 1.71, 95% CI 1.01 to 2.88; 1 study, n=1 016) and likely increased minor bleeding up to 12 months of follow-up compared to LMWH (RR 1.31, 95% CI 0.95 to 1.80; 1 study, n=1 016). Idraparinux versus vitamin K antagonists:One study (n=284) compared once-weekly subcutaneous injection of idraparinux versus standard treatment (parenteral anticoagulation followed by warfarin or acenocoumarol) for 3 or 6 months. There was no difference between idraparinux and VKAs in mortality at 6 months (RR 1.11, 95% CI 0.78 to 1.59), VTE recurrence at 6 months (RR 0.46, 95% CI 0.16 to 1.32) or major bleeding (RR 1.11, 95% CI 0.35 to 3.56).
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Primary/Secondary Keywords