D-dimer cutoff values for predicting functional prognosis in patients with severe head trauma: a multi-centre prospective observational study.

PURPOSE: D-dimer, a fibrinolysis indicator, may predict functional and life outcomes in traumatic brain injury (TBI) patients. We aimed to identify optimal D-dimer cutoff values for poor functional outcomes in severe TBI.

METHODS

We used data from a multi-centre prospective observational cohort study that included patients with TBI with a Glasgow Coma Scale (GCS) score ≤ 8 within 48 h after injury or required neurosurgical procedures. We selected patients admitted ≤ 1 h after injury. Neurological function at discharge was assessed using the modified Rankin Scale (mRS). The association between D-dimer levels at admission and neurological function (mRS ≥ 4 or < 4), adjusted for age, GCS, systolic blood pressure, and head abbreviated injury scale (AIS) score, was determined by logistic regression analysis. The predictive utility of D-dimer levels was assessed using the area under the receiver operating characteristic curve (AUC), with the cutoff value being determined using Youden's index.

RESULTS

Among the 336 patients, most were male; approximately half had experienced motor vehicle accidents. The median (interquartile range) of age, GCS scores, and head AIS scores were 65 (40.25 - 78.75) years, 7 (4 - 9), and 5 (4 - 5), respectively. Overall, 214 (63.7%) patients had poor neurological function (mRS ≥ 4). D-dimer levels > 28 µg/mL predicted poor functional prognosis (odds ratio = 3.84 [95% confidence interval 1.62 - 9.11]); the AUC and cutoff values were 0.73 and 27.2 µg/mL, respectively.

CONCLUSION

A cutoff value of 27.2 µg/mL for early-stage D-dimer levels could predict the functional prognosis of patients with severe isolated TBI.