Characteristics and Outcomes of Traumatic Acute Subdural Hematoma in Elderly Patients Receiving Antithrombotic Therapy: A Single-Center Retrospective Cohort Study

<b>Background:</b> Antithrombotic therapy is a risk factor for subdural hematoma after head injury. <b>Methods:</b> We retrospectively studied 180 consecutive patients with traumatic acute subdural hematoma. <b>Results</b>: The median age was 81 years, 68 (38%) were female, and 44% were on antithrombotic therapy. In the antithrombotic therapy group, the patients were significantly older (84, 77-88 vs. 78, 74-84, <i>p</i> value = 0.00104), and the proportion of minor injury was significantly higher (83% vs. 61%, <i>p</i> value = 0.00178). Poor clinical outcomes were not significantly different between the groups (44% vs. 41%; <i>p</i> value = 0.762). In multivariable logistic regression analysis adjusted for age and sex, poor outcomes (42%) were associated with the first Glasgow coma scale scores (OR 0.73, 95% CI 0.65-0.82, <i>p</i> value < 0.001) and the first CT findings (OR 4.9, 95% CI 1.98-11.8, <i>p</i> value < 0.001), but not with antithrombotic therapy (OR 1.48, 95% CI 0.61-3.60, <i>p</i> value = 0.390). Of the 97 patients treated conservatively for more than 2 weeks, surgical intervention in the chronic phase was higher in the antithrombotic therapy group (16% vs. 1.9%; <i>p</i> value = 0.0230). The timing of re-administration did not correlate with the incidence of chronic surgical intervention (within 2 weeks: 18%; over 2 weeks: 9.1%; <i>p</i> value = 0.663). <b>Conclusions:</b> The proportion of minor injury was significantly higher in the antithrombotic therapy group than in the non-medication group. Antithrombotic therapy was not associated with poor outcome but correlated with the increased risk of surgical intervention in the chronic phase.