e Compared with low-risk patients, moderate-risk patients are assumed to have a twofold risk and high-risk patients are assumed to have an eightfold risk of major bleeding.79,185,187,189,195,196,198,204 f We estimate that anticoagulation is associated with a 2.6-fold increase in major bleeding based on comparison of extended anticoagulation with no extended anticoagulation (Table 6 in AT91 ). The relative risk of major bleeding during the rst 3 mo of therapy may be greater that during extended VKA therapy because: (1) the intensity of anticoagulation with initial parenteral therapy may be greater that with VKA therapy; (2) anticoagulant control will be less stable during the rst 3 mo; and (3) predispositions to anticoagulant-induced bleeding may be uncovered during the rst 3 mo of therapy.189,198,203 However, studies of patients with acute coronary syndromes do not suggest a higher than 2.6 relative risk of major bleeding with parenteral anticoagulation (eg, UFH, LMWH) compared with control.219,220 g 1.6% corresponds to the average of major bleeding with initial UFH or LMWH therapy followed by VKA therapy (Table 7 in AT91 ). We estimated baseline risk by assuming a 2.6 relative risk of major bleeding with anticoagulation (footnote f). h Consistent with frequency of major bleeding observed by Hull in high- i Our estimated baseline risk of major bleeding for low-risk patients (and adjusted up for moderate- and high-risk groups as per footnote e). j Consistent with frequency of major bleeding during prospective studies of extended anticoagulation for VTE (Table 6 in AT91 been treated for 6 or for 12 months. In the same study, all patients without residual DVT after 6 months of LMWH stopped therapy and had a low risk of recurrence during the next year (three episodes in 91 patients). 