D-dimer levels on admission and all-cause mortality risk in COVID-19 patients: a meta-analysis

Abstract

D-dimer level on admission is a promising biomarker to predict mortality in patients with COVID-19. In this study, we reviewed the association between on-admission D-dimer levels and all-cause mortality risk in COVID-19 patients. Peer-reviewed studies and preprints reporting categorised D-dimer levels on admission and all-cause mortality until 24 May 2020 were searched for using the following keywords: 'COVID-19', 'D-dimer' and 'Mortality'. A meta-analysis was performed to determine the pooled risk ratio (RR) for all-cause mortality. In total, 2911 COVID-19 patients from nine studies were included in this meta-analysis. Regardless of the different D-dimer cut-off values used, the pooled RR for all-cause mortality in patients with elevated vs. normal on-admission D-dimer level was 4.77 (95% confidence interval (CI) 3.02-7.54). Sensitivity analysis did not significantly affect the overall mortality risk. Analysis restricted to studies with 0.5 μg/ml as the cut-off value resulted in a pooled RR for mortality of 4.60 (95% CI 2.72-7.79). Subgroup analysis showed that the pooled all-cause mortality risk was higher in Chinese vs. non-Chinese studies (RR 5.87; 95% CI 2.67-12.89 and RR 3.35; 95% CI 1.66-6.73; P = 0.29). On-admission D-dimer levels showed a promising prognostic role in predicting all-cause mortality in COVID-19 patients, elevated D-dimer levels were associated with increased risk of mortality.

Keywords: COVID-19; Coronavirus disease; D-dimer; mortality; prognosis.

Fig. 1.

PRISMA diagram showing the study selection for inclusion in the meta-analysis. Literature search identifying peer-reviewed papers, preprints and grey literature was done from database conception to 24 May 2020.

Fig. 2.

All-cause mortality risk. Forest plot using the Mantel–Haenszel random-effect model demonstrating the association between D-dimer levels on admission and all-cause mortality risk for all included studies.

Fig. 3.

All-cause mortality risk for studies with D-dimer cut-off value of 0.5 μg/ml. Forest plot using the Mantel–Haenszel fixed-effect model showing the association between D-dimer levels on admission and all-cause mortality risk for studies with D-dimer cut-off value of 0.5 μg/ml.

Fig. 4.

Subgroup analysis by study location. Forest plot using the Mantel–Haenszel random-effect model comparing the association between D-dimer levels on admission and all-cause mortality risk in Chinese and non-Chinese studies. Non-Chinese studies included studies done in the USA and Italy.