Dr Jacob Cao
The case for extended thromboprophylaxis in medical patients beyond discharge is not yet made because the benefits of VTE prevention do not outweigh the risk of a major bleed, the Australian authors of a meta-analysis say.
While extended use of direct acting oral anticoagulants in medically hospitalised patients halved the risk of symptomatic VTE and non-fatal pulmonary embolism, it was also doubled the risk of major bleeding, according to a systematic review conducted by Dr Jacob Cao and Professor Anthony Keech of the Department of Cardiology, Royal Prince Alfred Hospital, Sydney.
Writing in the European Journal of Preventive Cardiology, they said there was established evidence to support the benefits of short-term VTE thromboprophylaxis for medically hospitalised patients, but the case for prophylaxis extended beyond discharge had not been clear, with five randomised controlled trials of DOACS giving conflicting results and with complex composite outcomes.
In their meta-analysis of the trials, which involved 20,046 extended and 20,078 standard duration thromboprophylaxis patients, they found that allocation to extended treatment significantly reduced the risk of symptomatic DVT (Relative Risk 0.47) and non-fatal PE (RR 0.59) compared to standard treatment.
There was no significant difference in the risk of VTE-related death (RR 0.81 for extended vs standard treatment). Extended treatment also increased the risk of major bleeding (RR 2.04), had no significant impact on the risks of bleeding-related death and intracranial haemorrhages.
The estimated Number Needed to Treat (NNT) to prevent at least one symptomatic DVT and non-fatal PE were 405 and 732, respectively, while the Number Needed to Harm (NNH) for major bleeding was 310.
The estimated costs to prevent one symptomatic DVT and non-fatal PE were A$45,900 and $83,000 respectively.
The review authors said their findings showed there was not yet a strong case to change current guidelines that advise against extended duration thromboprophylaxis , though they did suggest there was a need for additional trials to investigate the role of extended thromboprophylaxis in high risk individuals.
“The cost of providing such extended treatment, in addition to the need to manage the higher incidence of bleeding events, appears more than the hospital savings associated with preventing VTE-related events and their treatment,” they noted.
“On account of no statistically significant benefit for VTE-related death and a lack of trials investigating benefits selectively in patients at high risk of symptomatic VTE, there can be no basis currently for recommending any changes to contemporary policy and practice,” they concluded.