Case Fatality Rates of Recurrent Venous Thromboembolism during and Following Anticoagulation Therapy

Abstract

Background: The optimal duration of anticoagulation treatment in patients with unprovoked VTE is unknown. In order to counsel VTE patients on the risks and benefits of discontinuing anticoagulants, clinicians need to balance the long-term risk of recurrent VTE with major bleeding on anticoagulants. For all VTE patients on oral anticoagulant, the case-fatality rate of major bleeding was previously reported to be 13.4% (95% confidence intervals (CI): 9.4% to 17.4%). A major knowledge gap exists regarding the case-fatality rate of recurrent pulmonary embolism (PE) during and following anticoagulation therapy for VTE.Purpose: To summarize the case fatality rate of recurrent VTE during and following anticoagulation therapy.Data Source: A systematic literature search strategy was conducted using MEDLINE, EMBASE, the Cochrane Register of Controlled Trials and all EBM Reviews. Study Outcome: We selected 62 studies that reported the rates of fatal PE in patients with recurrent VTE. Fatal PE was defined asconfirmed autopsy report;death preceding with confirmed deep vein thrombosis (DVT) or non-fatal PE;sudden death not explained by a condition other than PE.Measurements: Pooled case fatality rates were generated. Ninety-five percent CI were calculated for each case fatality rate using averaged, inverse variance-weighted estimates from each study.Data Synthesis: 30,885 VTE patients were included (17,650 DVT, 8801 PE and 4434 DVT or PELimitations: Unable to determine the case fatality rate by etiology of VTE (i.e. provoked, unprovoked).Conclusion: Case fatality rates for recurrent VTE are elevated during and following anticoagulation treatment for VTE but appear lower than the case-fatality rate for major bleeding with oral anticoagulants. This information must be considered by clinicians when counseling patients on whether to continue or discontinue anticoagulant therapy following VTE. Not only must absolute recurrent VTE and major bleeding rates be compared between groups that continue and discontinue anticoagulants but the relative consequences (i.e. case fatality rates) must be also considered with more weight placed on major bleeding episodes.Initial eventDuring anticoagulation Treatment (%, 95% CI)Following anticoagulation Treatment (%, 95% CI)DVT10.6 (8.3–13.0)7.3 (5.0–9.7)PE12.3 (5.9–18.7)12.5 (6.4–28.7)Any event10.2 (7.9–12.5)9.0 (7.3–10.8)