To the Editor The decision to initiate oral anticoagulation (OAC) posthemorrhagic stroke or traumatic intracerebral hemorrhage (ICH) in those with atrial fibrillation (AF) is a gray area in clinical practice. By showing that the decision to resume OAC may have a favorable risk-benefit ratio, the article by Nielsen et al1 published in a recent issue of JAMA Internal Medicine brings us closer to understanding if and when to do this. However, important questions remain, which may be difficult to clarify using such an observational approach.