key: cord-0696637-shakv9ht
authors: Shi, Li; Wang, Ying; Wang, Yadong; Duan, Guangcai; Yang, Haiyan
title: An updated meta‐analysis on the relationship between D‐dimer levels and severity of coronavirus disease 2019
date: 2020-06-18
journal: Int J Lab Hematol
DOI: 10.1111/ijlh.13268
sha: 3cb3fab5d97cac0f2fbb5aab4a677479dada114d
doc_id: 696637
cord_uid: shakv9ht

nan

tion. 1 It has been shown that many laboratory abnormalities might predict adverse outcomes including increased D-dimer values. (Table S1 ). 4 An electronic search was applied to PubMed, Web of Science, and medRxiv (https://conne ct.medrx iv.org/relat e/conte nt/181) databases, using the following search terms: "coronavirus" OR "2019-nCoV" OR "SARS-CoV-2" OR "COVID-19" AND "laboratory," between January 1, 2020, and April 7, 2020. We screened the titles and abstracts of the studies and then enrolled the studies that documented the characteristic of D-dimer levels in non-severe and severe patients with COVID-19 by reading full texts. Severe COVID-19 patients included those with acute respiratory distress syndrome, admitted to the intensive care unit, or died. 3, 5 Because of the existence of unit differences and high heterogeneity, the standardized mean difference (SMD) with 95% CI and the odds ratio (OR) with the corresponding 95% CI were calculated in severe patients versus non-severe patients through a random-effects model. 6 We estimated the mean and standard deviation according to Wan et al 7 when sample size, median, and interquartile range (IQR) were provided. All calculations were undertaken in STATA 11.2. An 11-item checklist recommended by the Agency for Healthcare Research and Quality (AHRQ) was applied to assess the quality of included studies. 8 Initially, 1930 studies were identified. As a result, 21 studies with 3657 patients were included in the synthesis. All the patients in the included studies were from China. The units of D-dimer were varied in the eligible studies, including mg/L, mg/mL, μg/mL, ng/mL, and μg/L. The quality scores ranged from 4 to 8. All studies were considered to be of high or moderate quality (Table S2) Table 1 .

The pooled SMD indicated that the D-dimer levels of severe patients were higher than that of non-severe patients (SMD = 0.97, 95% CI = 0.77-1.17; I 2 = 75.7%, P < .001; random-effects model) ( Figure 1A ). As Figure 1B showed that D-dimer elevation was more likely to be detected in severe COVID-19 patients (OR = 3.27, 95% CI = 1.64-6.51; I 2 = 68.9%, P = .022; random-effects model). The similar results were observed in non-survival COVID-19 patients (OR = 9.51, 95% CI = 3.23-28.06; random-effects model).

Although the definitions of severe COVID-19 were different across these included studies (Table S3) , which may result in higher heterogeneity, our study found that elevated D-dimer was an important feature of severe COVID-19 patients. Elevation of D-dimer is a marker of thrombosis and is also one of the diagnostic criteria for disseminated intravascular coagulation (DIC). Thrombosis and/or DIC may occur in many severe COVID-19-infected patients. 9 Thus, corresponding timely treatment for these patients on this basis is indicated, for example, anticoagulant therapy if appropriate. 

This study was supported by a grant from the National Natural Science Foundation of China (No. 81973105).

All authors report that they have no potential conflict of interest.

Li Shi collected, extracted, and analyzed the data of eligible studies and wrote the manuscript; Ying Wang took part in the data extraction and statistical analysis; Yadong Wang contributed to statistical analysis and revision of manuscript; Guangcai Duan helped to revise the manuscript; Haiyan Yang designed the study; and each author has read and approved the final manuscript.

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