Plasma D-dimer levels are a biomarker for in-hospital complications and long-term mortality in patients with traumatic brain injury

Abstract

Introduction: Traumatic brain injury (TBI) is a major health concern worldwide. D-dimer levels, commonly used in the diagnosis and treatment of neurological diseases, may be associated with adverse events in patients with TBI. However, the relationship between D-dimer levels, TBI-related in-hospital complications, and long-term mortality in patients with TBI has not been investigated. Here, examined whether elevated D-dimer levels facilitate the prediction of in-hospital complications and mortality in patients with TBI.

Methods: Overall, 1,338 patients with TBI admitted to our institute between January 2016 and June 2022 were retrospectively examined. D-dimer levels were assessed within 24 h of admission, and propensity score matching was used to adjust for baseline characteristics.

Results: Among the in-hospital complications, high D-dimer levels were associated with electrolyte metabolism disorders, pulmonary infections, and intensive care unit admission (p < 0.05). Compared with patients with low (0.00-1.54 mg/L) D-dimer levels, the odds of long-term mortality were significantly higher in all other patients, including those with D-dimer levels between 1.55 mg/L and 6.35 mg/L (adjusted hazard ratio [aHR] 1.655, 95% CI 0.9632.843), 6.36 mg/L and 19.99 mg/L (aHR 2.38, 95% CI 1.416-4.000), and >20 mg/L (aHR 3.635, 95% CI 2.195-6.018; p < 0.001). D-dimer levels were positively correlated with the risk of death when the D-dimer level reached 6.82 mg/L.

Conclusion: Overall, elevated D-dimer levels at admission were associated with adverse outcomes and may predict poor prognosis in patients with TBI. Our findings will aid in the acute diagnosis, classification, and management of TBI.

Keywords: D-dimer; biomarker; in-hospital complications; long-term mortality; prognosis prediction; traumatic brain injury.

Figure 1

Flow chart of the patient selection process and statistical analysis method.

Figure 2

Kaplan–Meier analysis showing the four groups of D-dimer levels in relation to 1-month mortality (A), 1-year mortality (B), and long-term mortality (C) after traumatic brain injury (TBI) (P_a < 0.0001, P_b < 0.0001, P_c < 0.0001). As shown in (C), at 2500 days, 5, 4, 6, and 2 patients in the four groups (G1–G4, respectively) did not experience any outcome events and were still being followed up with.

Figure 3

Subgroup analyses of the association between D-dimer levels and long-term mortality with a multivariate model adjusted for age, operation treatment, Glasgow Coma Scale (GCS) score, and concentrations of hemoglobin (HB), platelets (Plt), fibrinogen, prothrombin time (PT), activated partial thromboplastin time (APTT), and thrombin time (TT).

Figure 4

Time-dependent receiver operating characteristic curve for prediction of D-dimer levels in patients with traumatic brain injury. (A) Unadjusted time-dependent ROC curve; (B) PSM adjusted time-dependent ROC curve. AUC, area under the curve; ROC, receiver operating characteristic; PSM, propensity score matching.

Figure 5

Restricted cubic spline showing the association between D-dimer levels and long-term mortality. (A) Unadjusted restricted cubic spline curve; (B) PSM adjusted restricted cubic spline curve. CI, confidence interval; PSM, propensity score matching.

Figure 6

High D-dimer levels within 24 h of admission were associated with complications and mortality in TBI patients. TBI, traumatic brain injury.