Patients with subdural hemorrhage (SDH) and a Glasgow Coma Scale (GCS) score of 13–15 are typically categorized as having mild traumatic brain injury. We hypothesize that patients without a maximum GCS score – specifically, patients with GCS scores of 13 and 14 – may exhibit poorer neurological outcomes.

Between January 1, 2019, and December 31, 2020, SDH patients with GCS scores ranging from 13 to 15 were retrospectively studied. We compared outcomes between patients with a maximum GCS score of 15 and those with scores of either 13 or 14. Independent factors associated with neurological deterioration among patients with a GCS score of 15 were evaluated using multivariate logistic regression (MLR) analysis.

During the study period, 470 patients with SDH and GCS scores between 13 and 15 were examined. Compared to patients with a maximum GCS score (N = 375), those in the GCS 13–14 group (N = 95) showed significantly higher rates of neurological deterioration (33.7% vs. 10.4%, p value <0.001) and neurosurgical interventions (26.3% vs. 16.3%, p value <0.024). Moreover, the GCS 13–14 group had a significantly poorer prognosis than patients with a GCS score of 15 [mortality rate: 7.4% vs. 2.4%, p value <0.017; rate of impaired consciousness at discharge: 21.1% vs. 4.0%, p value <0.001; and rate of neurological disability at discharge: 29.5% vs. 6.9%, p value <0.001]. The MLR analysis revealed that SDH thickness (odds ratio = 1.127, p value = 0.006) was an independent risk factor for neurological disability at discharge in patients with a GCS score of 15.

Among SDH patients with mild TBI, those with GCS scores of 13–14 exhibited poorer neurological outcomes than those with a maximum GCS score. The thickness of the SDH is positively associated with neurological disability in SDH patients with a maximum GCS score.