The Association Between D-dimer Levels and Long-Term Neurological Outcomes of Patients with Traumatic Brain Injury: An Analysis of a Nationwide Observational Neurotrauma Database in Japan

[Background] We evaluated the association between D-dimer (DD) levels and long-term neurological prognoses among patients with isolated traumatic brain injury. [Methods] Using data from multiple centers in the Japanese Neurotrauma Data Bank, we conducted an observational retrospective cohort study. Patients with isolated traumatic brain injury (head Abbreviated Injury Scale score > 2; any other Abbreviated Injury Scale score < 3) who were registered in the Japanese Neurotrauma Data Bank from 2015 to 2017 were recruited. We excluded patients younger than age 16 years and those who developed cardiac arrest at hospital admission. We also excluded patients with unknown Glasgow Outcome Scale (GOS) scores at 6 months after injury and those with unknown DD levels. The primary outcome was the association of DD levels with GOS scores at 6 months. We defined GOS scores 1 to 3 as poor and GOS scores 4 and 5 as good. The secondary outcome was the association of DD levels with mortality at 6 months after injury. We conducted multivariate logistic regression analyses to calculate the adjusted odds ratios of DD levels at hospital admission and GOS scores at 6 months as tertiles with 95% confidence intervals (CIs). A total of 293 patients were enrolled (median age 67 years; interquartile range 51–79 years). The median DD level was 27.1 mg/L (interquartile range 9.7–70.8 mg/L), and 58.0% (n = 170) had poor GOS scores at 6 months. [Results] The multivariable logistic regression analysis indicated that the adjusted odds ratios were 2.52 (95% CI 1.10–5.77) for middle DD levels with poor GOS scores at 6 months and 5.81 (95% CI 2.37–14.2) for high DD levels with poor GOS scores at 6 months. [Conclusions] We revealed an association between DD levels and poor long-term neurological outcomes among patients with isolated traumatic brain injury