D-Dimer and the Short-Term Prognosis of Patients with Subarachnoid Hemorrhage: A Meta-Analysis

Introduction: Elevated plasma D-dimer has been observed in acute phase of subarachnoid hemorrhage (SAH), while a quantitative evaluation for the association between D-dimer level and prognosis of SAH remains lacking. The aim of the meta-analysis was to investigate the potential predictive role of D-dimer for the short-term functional outcome of patients with SAH. Methods: Relevant observational studies were retrieved by searching PubMed, Web of Science, Embase, Wanfang, and CNKI. A poor functional outcome was generally defined by the Glasgow Outcome Scale (1–3) or the modified Rankin Scale (≥3). A random-effects model was used to combine the data by incorporating the influence of between-study heterogeneity. Results: Eleven studies involving 3,748 patients with SAH were included. Among them, 1,131 patients (30.2%) developed a poor functional outcome within 6 months. The pooled results showed that a higher plasma D-dimer at admission was associated with a higher risk of poor functional outcome during follow-up (odds ratio per 1 mg/L increment of D-dimer: 1.65, 95% confidence interval: 1.49–1.82, p < 0.001; I² = 0%). Sensitivity analysis by excluding one study at a time showed similar results. Subgroup analyses suggested that the association between D-dimer and poor functional outcome of patients with SAH was not significantly affected by study design, country, mean age, proportion of men, follow-up duration, methods for defining poor outcome, study quality scores, timing of D-dimer measurement, or the publication year. Conclusion: A high plasma D-dimer at admission is associated with a poor short-term functional outcome of patients with SAH.