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Background: Delayed intracranial hemorrhage (ICH) after head injury in older patients taking anticoagulants has been reported to be as high as 7.2%. Other studies suggest much lower rates. Its incidence and clinical management are controversial, with some recommending observation and repeat head imaging at 24 h.

Objective: Our study aims to assess the incidence of delayed ICH in geriatric Emergency Department (ED) head trauma patients prescribed preinjury anticoagulants.

Methods: We performed a prospective cohort study conducted at two hospital EDs from August 2019 to July 2020. All patients aged 65 years or older with acute head injury were eligible for enrollment. We conducted telephone follow-up at 14 and 60 days, and a chart review at 90 days. The primary study outcome was incidence of delayed ICH, which was defined as an initial negative head computed tomography scan followed by subsequent ICH believed to be caused by the initial traumatic event. We compared the rates of delayed ICH between patient cohorts based on anticoagulant use.

Results: There were 3425 patients enrolled: 2300 (67.2%) were not on an anticoagulant, 249 (7%) were on preinjury warfarin, 780 (22.7%) were on a direct-acting oral anticoagulant, and 96 (2.8%) were on enoxaparin or heparin. The median age was 82 years (interquartile range 65-107), the majority were female (55.2%), and almost all were Caucasian (84.3%). An acute ICH was identified in 229 of 3425 (6.7%, 95% confidence interval 68%) and delayed ICH in 13 (0.4%, 95% confidence interval 0.2–0.6%). There were no differences in rates of delayed ICH between those who had been prescribed anticoagulants vs. those who had not ( p = 0.45).

Conclusions: The incidence of delayed ICH is very low in older ED head trauma patients on prescribed pre-injury anticoagulants. Our data have important clinical implications for the management of blunt head trauma among older ED patients on anticoagulants.