Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Meta-Analysis
. 2021 Apr:42:60-69.
doi: 10.1016/j.ajem.2021.01.006. Epub 2021 Jan 9.

Neutrophil-to-lymphocyte ratio on admission to predict the severity and mortality of COVID-19 patients: A meta-analysis

Daniel Martin Simadibrata  1 , Julius Calvin  2 , Alya Darin Wijaya  2 , Naufal Arkan Abiyyu Ibrahim  2
Affiliations
Meta-Analysis

Neutrophil-to-lymphocyte ratio on admission to predict the severity and mortality of COVID-19 patients: A meta-analysis

Daniel Martin Simadibrata et al. Am J Emerg Med. 2021 Apr.

Abstract

Background: The neutrophil-to-lymphocyte ratio (NLR), an inflammatory marker, was suggested to be predictive of severity and mortality in COVID-19 patients. Here, we investigated whether NLR levels on admission could predict the severity and mortality of COVID-19 patients.

Methods: A literature search was conducted on 23 July 2020 to retrieve all published articles, including grey literature and preprints, investigating the association between on-admission NLR values and severity or mortality in COVID-19 patients. A meta-analysis was performed to determine the overall standardized mean difference (SMD) in NLR values and the pooled risk ratio (RR) for severity and mortality with the 95% Confidence Interval (95%CI).

Results: A total of 38 articles, including 5699 patients with severity outcomes and 6033 patients with mortality outcomes, were included. The meta-analysis showed that severe and non-survivors of COVID-19 had higher on-admission NLR levels than non-severe and survivors (SMD 0.88; 95%CI 0.72-1.04; I2 = 75.52% and 1.87; 95%CI 1.25-2.49; I2 = 97.81%, respectively). Regardless of the different NLR cut-off values, the pooled mortality RR in patients with elevated vs. normal NLR levels was 2.74 (95%CI 0.98-7.66).

Conclusion: High NLR levels on admission were associated with severe COVID-19 and mortality. Further studies need to focus on determining the optimal cut-off value for NLR before clinical use.

Keywords: COVID-19; Meta-analysis; Mortality; Neutrophil-to-lymphocyte ratio; Severity.

PubMed Disclaimer

Conflict of interest statement

Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Fig. 1
Fig. 1
Prisma diagram for study selection. A systematic literature search was done on 23 July 2020 to identify peer-reviewed papers, preprints, and grey literature.
Fig. 2
Fig. 2
Neutrophil-to-lymphocyte ratio (NLR) value on admission in severe vs. non-severe COVID-19 patients. A) Forest Plot for all included studies using the DerSimonian-Laird random-effect models showing elevated NLR values on admission in severe compared to non-severe COVID-19. B) Publication bias analysis of all included studies using the Funnel Plot indicating a potential publication bias.
Fig. 3
Fig. 3
Bubble plot for meta-regression. The association between NLR values on admission and severity of COVID-19 (A) and COVID-19 mortality (B) was not affected by age (p = 0.236; p = 0.595, respectively).
Fig. 4
Fig. 4
Neutrophil-to-lymphocyte ratio (NLR) value on admission in non-survivor vs. survivor of COVID-19 patients. A) Forest Plot for all included studies using the DerSimonian-Laird random-effects model showing elevated NLR values on admission in non-survivors compared to survivors of COVID-19. B) Publication bias analysis of all included studies using the Funnel Plot indicating a potential publication bias. C) Forest Plot using the DerSimonian-Laird random-effects model showing the association between NLR value on admission and all-cause mortality risk.
See this image and copyright information in PMC

References

    1. Liu Y.-C., Kuo R.-L., Shih S.-R. COVID-19: The first documented coronavirus pandemic in history. Biomedical J. 2020 doi: 10.1016/j.bj.2020.04.007. - DOI - PMC - PubMed
    1. World Health Organization WHO Coronavirus Disease (COVID-19) 2020. https://covid19.who.int/ Dashboard.
    1. Sun P., Lu X., Xu C., Sun W., Pan B. Understanding of COVID-19 based on current evidence. J Med Virol. 2020;92(6):548–551. doi: 10.1002/jmv.25722. - DOI - PMC - PubMed
    1. Chen Y., Liu Q., Guo D. Emerging coronaviruses: genome structure, replication, and pathogenesis. J Med Virol. 2020;92(4):418–423. doi: 10.1002/jmv.25681. - DOI - PMC - PubMed
    1. Cascella M., Rajnik M., Cuomo A., Dulebohn S.C., Di Napoli R. StatPearls; Treasure Island (FL): 2020. Features, evaluation and treatment coronavirus (COVID-19) - PubMed