Long-term anticoagulant therapy for idiopathic pulmonary embolism in the elderly: A decision analysis

Background: Elderly patients with idiopathic pulmonary embolism (PE) are at high risk for recurrent venous thromboembolic disease and might benefit from long-term anticoagulant therapy. But they are also at higher risk for bleeding complications. Because there have been no clinical trials addressing PE treatment in elderly patients, the balance of therapeutic benefits and risks is unclear. Methods: We constructed a decision-analytic model to forecast the effects of long-term warfarin therapy for idiopathic PE. We focused on 65- and 80-year-old outpatients, with or without a propensity for falls, who previously had completed 6 to 12 months of anticoagulant therapy without experiencing a major bleed. The model incorporated age-appropriate thromboembolic recurrence rates after PE, major bleeding risks of warfarin use, and the contribution of falls to major bleeding episodes in anticoagulated elderly patients. We used probabilistic sensitivity analysis to model outcomes over ranges of potential thromboembolic and bleeding risks. Results: In our baseline analysis, long-term warfarin was superior to conventional duration therapy. Depending on the patient subgroup (stratified by age and fall risk), it increased life expectancy by 0.16 to 0.56 years and event-free life expectancy by 0.32 to 0.51 years. Probabilistic sensitivity analysis demonstrated that long-term warfarin therapy was likely to increase life expectancy when compared with conventional-duration therapy (76 to 93% likelihood across all groups). Conclusions: Extended anticoagulant therapy for idiopathic PE may be beneficial in a subgroup of elderly patients who tolerate the initial 6 to 12 months of therapy without bleeding complications. In this population, advanced age and fall risk were not contraindications to long-term anticoagulation.