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Neutrophil-to-lymphocyte ratio as a prognostic indicator in COVID-19 : Evidence from a northern tanzanian cohort

Kyala, Norman Jonas ; Mboya, Innocent LU orcid ; Shao, Elichilia ; Sakita, Francis ; Kilonzo, Kajiru Gadiel ; Shirima, Laura ; Sadiq, Abid ; Mkwizu, Elifuraha ; Chamba, Nyasatu and Marandu, Annette , et al. (2025) In PLoS ONE 20(1 January).
Abstract

Background: COVID-19 caused a profound global impact, resulting in significant cases and deaths. The progression of COVID-19 clinical manifestations is influenced by a dysregulated inflammatory response. Early identification of the subclinical progression is crucial for timely intervention and improved patient outcomes. While there are various biomarkers to predict disease severity and outcomes, their accessibility and affordability pose challenges in resource-limited settings. We explored the potentiality of the neutrophil-to-lymphocyte ratio (NLR) as a cost-effective inflammatory marker to predict disease severity, clinical deterioration, and mortality in affected patients. Methodology: A hospital-based retrospective cohort study was... (More)

Background: COVID-19 caused a profound global impact, resulting in significant cases and deaths. The progression of COVID-19 clinical manifestations is influenced by a dysregulated inflammatory response. Early identification of the subclinical progression is crucial for timely intervention and improved patient outcomes. While there are various biomarkers to predict disease severity and outcomes, their accessibility and affordability pose challenges in resource-limited settings. We explored the potentiality of the neutrophil-to-lymphocyte ratio (NLR) as a cost-effective inflammatory marker to predict disease severity, clinical deterioration, and mortality in affected patients. Methodology: A hospital-based retrospective cohort study was conducted at KCMC Hospital among COVID-19 patients followed from admission to discharge between 1st March 2020 and 31st March 2022. NLR was calculated as the absolute neutrophil count in μL divided by the absolute lymphocyte count in μL. The NLR cut-off value was determined using Receiver Operating Characteristic (ROC) analysis and assessed its predictive ability at admission for in-hospital mortality. The Chi-square test compared the proportion of NLR by patient characteristics. The association of NLR with disease severity and mortality was analyzed using the modified Poisson and Cox regression models, respectively. Results: The study included 504 patients, with a median age of 64 years, 57.1% were males, and 68.3% had severe COVID-19. The in-hospital COVID-19 mortality rate was 37.7%. An NLR cutoff value of 6.1 or higher had a sensitivity of 92.1% (95% CI 89.2%–94.0%) and a specificity of 92.0% (95% CI 89.7%–94.4%). Additionally, 39.5% of patients with an NLR value of 6.1 or higher had increased risk of severe disease, subsequent clinical deterioration, and mortality. Conclusion and recommendation: An NLR value of 6.1 or higher at the time of hospital admission associated with severe disease, clinical deterioration, and mortality in patients with COVID-19. Integration of NLR as a prognostic parameter in COVID-19 prognosis scales could improve risk assessment and guide appropriate management strategies for COVID-19 patients, as well as for potential future viral-related pneumonias. Further prospective studies are necessary to validate these findings and evaluate the clinical utility of NLR in larger cohorts of patients.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
PLoS ONE
volume
20
issue
1 January
article number
e0300231
publisher
Public Library of Science (PLoS)
external identifiers
  • scopus:85216878503
  • pmid:39888959
ISSN
1932-6203
DOI
10.1371/journal.pone.0300231
language
English
LU publication?
yes
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Publisher Copyright: © 2025 Kyala et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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3b71ef1b-506b-40cb-bb12-451bea87d134
date added to LUP
2025-04-10 10:12:29
date last changed
2025-07-17 17:58:04
@article{3b71ef1b-506b-40cb-bb12-451bea87d134,
  abstract     = {{<p>Background: COVID-19 caused a profound global impact, resulting in significant cases and deaths. The progression of COVID-19 clinical manifestations is influenced by a dysregulated inflammatory response. Early identification of the subclinical progression is crucial for timely intervention and improved patient outcomes. While there are various biomarkers to predict disease severity and outcomes, their accessibility and affordability pose challenges in resource-limited settings. We explored the potentiality of the neutrophil-to-lymphocyte ratio (NLR) as a cost-effective inflammatory marker to predict disease severity, clinical deterioration, and mortality in affected patients. Methodology: A hospital-based retrospective cohort study was conducted at KCMC Hospital among COVID-19 patients followed from admission to discharge between 1st March 2020 and 31st March 2022. NLR was calculated as the absolute neutrophil count in μL divided by the absolute lymphocyte count in μL. The NLR cut-off value was determined using Receiver Operating Characteristic (ROC) analysis and assessed its predictive ability at admission for in-hospital mortality. The Chi-square test compared the proportion of NLR by patient characteristics. The association of NLR with disease severity and mortality was analyzed using the modified Poisson and Cox regression models, respectively. Results: The study included 504 patients, with a median age of 64 years, 57.1% were males, and 68.3% had severe COVID-19. The in-hospital COVID-19 mortality rate was 37.7%. An NLR cutoff value of 6.1 or higher had a sensitivity of 92.1% (95% CI 89.2%–94.0%) and a specificity of 92.0% (95% CI 89.7%–94.4%). Additionally, 39.5% of patients with an NLR value of 6.1 or higher had increased risk of severe disease, subsequent clinical deterioration, and mortality. Conclusion and recommendation: An NLR value of 6.1 or higher at the time of hospital admission associated with severe disease, clinical deterioration, and mortality in patients with COVID-19. Integration of NLR as a prognostic parameter in COVID-19 prognosis scales could improve risk assessment and guide appropriate management strategies for COVID-19 patients, as well as for potential future viral-related pneumonias. Further prospective studies are necessary to validate these findings and evaluate the clinical utility of NLR in larger cohorts of patients.</p>}},
  author       = {{Kyala, Norman Jonas and Mboya, Innocent and Shao, Elichilia and Sakita, Francis and Kilonzo, Kajiru Gadiel and Shirima, Laura and Sadiq, Abid and Mkwizu, Elifuraha and Chamba, Nyasatu and Marandu, Annette and Muhali, Sophia and Raza, Faryal and Ndale, Eliasa and Bayo, Damas and Mujuni, Daniel and Lyamuya, Furaha}},
  issn         = {{1932-6203}},
  language     = {{eng}},
  number       = {{1 January}},
  publisher    = {{Public Library of Science (PLoS)}},
  series       = {{PLoS ONE}},
  title        = {{Neutrophil-to-lymphocyte ratio as a prognostic indicator in COVID-19 : Evidence from a northern tanzanian cohort}},
  url          = {{http://dx.doi.org/10.1371/journal.pone.0300231}},
  doi          = {{10.1371/journal.pone.0300231}},
  volume       = {{20}},
  year         = {{2025}},
}