Predictive roles of D-dimer for mortality of patients with community-acquired pneumonia: a systematic review and meta-analysis

OBJECTIVE: To explore the predictive roles of D-dimer for the mortality of patients with community-acquired pneumonia (CAP). METHODS: This was a systematic review and meta-analysis. We searched the following databases: PubMed, EMBASE, Web of Science, Ovid MEDLINE, and Cochrane Library from their inception to July 26, 2020. Studies exploring the relationship between blood D-dimer levels and CAP-related mortality were selected. In this meta-analysis, we calculated mortality rates, sensitivity, specificity, positive likelihood ratios, and negative likelihood ratios. RESULTS: The search identified 1,073 articles, 8 of which (a total of 2,126 patients) were included in this meta-analysis. The pooled mortality rate of the overall sample was 0.10 (95% CI, 0.08-0.14). The levels of blood D-dimer in the nonsurvivors were significantly higher than those in the survivors (weighted mean difference = 1.03 mg/L [95% CI, 0.81-1.26]; p < 0.00001). The area under the summary ROC curve for the optimal cutoff value of D-dimer as a predictor of mortality was 0.848 (SE = 0.046), and the pooled negative likelihood ratio for D-dimer within the normal range was 0.24 (95% CI, 0.11-0.53). CONCLUSIONS: Blood D-dimer might be helpful for the initial assessment of mortality risk of patients with CAP. D-dimer levels within the normal range indicate low risk of mortality. Because of the small sample size in our study, our findings should be further explored and validated in future studies with larger sample sizes.