The risk for fatal pulmonary embolism after discontinuing anticoagulant therapy for venous thromboembolism.

BACKGROUND: The long-term risk for fatal pulmonary embolism (PE) after treatment of venous thromboembolism (VTE) may be an important factor in the decision to discontinue this treatment.

OBJECTIVE: To provide reliable and precise estimates of the annual risk for fatal PE and the case-fatality rate of disease recurrence and to assess these outcomes according to the initial presentation of VTE (deep venous thrombosis [DVT], PE, or both) and its etiology (secondary or idiopathic) in patients who have discontinued anticoagulant therapy.

DESIGN: Prospective cohort study.

SETTING: Academic medical centers.

PATIENTS: Inception cohort of patients with a first episode of symptomatic VTE who discontinued anticoagulant therapy.

MEASUREMENTS: Incidence rates of any fatal PE (which included sudden death from possible fatal PE) and definite or probable PE per 100 person-years of follow-up and case-fatality rate of recurrent VTE.

RESULTS: Of 2052 patients studied, 1450 had DVT, 310 had PE, and 292 had DVT and PE. The mean duration of previous anticoagulant therapy was 6 months (range, 3 to 39 months), and the mean duration of follow-up after discontinuation of treatment was 54 months (range, 1 to 120 months). The annual risk for any fatal PE and definite or probable fatal PE after discontinuation of anticoagulation was 0.49 events (95% CI, 0.36 to 0.64 events) per 100 person-years and 0.19 events (CI, 0.12 to 0.30 events) per 100 person-years, respectively. The case-fatality rate of recurrent disease was 9.0% (CI, 6.8% to 11.8%) for any fatal PE and 3.8% (CI, 2.4% to 5.9%) for definite or probable fatal PE.

LIMITATION: The findings are less pertinent to patients with active cancer, permanent immobility, or high-risk thrombophilia.

CONCLUSION: The risk for fatal PE is 0.19 to 0.49 events per 100 person-years for patients who have finished a course of anticoagulant therapy for a first episode of symptomatic VTE. The case-fatality rate for death from recurrent PE is 4% to 9%. This information helps to inform patient prognosis and may assist clinicians in deciding whether to discontinue anticoagulant therapy for VTE.