A large cohort study did not find net clinical benefit of warfarin for AF patients with a CHADS2 score of 1,417 and a decision-analysis model predicted that anticoagulation would be beneficial in this group only when the lower risk of ICH associated with the newer agents was assumed.418 Most guidelines have not explicitly incorporated risk for anticoagulant-related hemorrhagic complications, largely because of the paucity of precise data on the risk of bleeding. Some of the risks for hemorrhage are also risks for cardio- embolism and thus do not necessarily argue against antico- agulation. Age >75 years, for example, is a factor favoring rather than opposing anticoagulation.377 One bleeding risk that appears sufficient to tip the balance away from anticoagula- tion in nonvalvular AF is a history of lobar ICH suggestive of cerebral amyloid angiopathy.419 Other risks for ICH such as certain genetic profiles or the presence of asymptomatic cerebral microbleeds on neuroimaging do not currently appear sufficient by themselves to outweigh the benefits of antico- agulation in patients at average risk of cardioembolism.420 For patients treated with adjusted-dose warfarin, the initial 3-month period is a particularly high-risk period for bleeding421 and requires especially close anticoagulation monitoring. 