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

Abstract

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.