Evaluating the neutrophil-to-lymphocyte ratio as an indicator for early referral of patients with COVID-19 pneumonia to a high-care facility
DOI:
https://doi.org/10.7196/SAMJ.2022.v112i10.16590Keywords:
neutrophil-to-lymphocyte ratioAbstract
Background. Early identification of patients at high risk of severe disease requiring referral and treatment at a high‐care facility is imperative in the management of COVID‐19 pneumonia in a limited‐resource setting, as transfer of unstable patients can be detrimental.
Objectives. To examine the value of the neutrophil‐to‐lymphocyte ratio (NLR) calculated on admission to a healthcare facility as a predictor of the need for early referral to a high‐care facility for further treatment.
Methods. We designed a cohort analytical study of 198 patients with COVID‐19 pneumonia admitted to the COVID‐19 unit at Universitas Academic Hospital in Bloemfontein, South Africa, between 20 May and 30 September 2021.
Results. Of the 198 patients enrolled in the study, 134 (67.7%) were admitted to high care and 93 (46.9%) died. The median (interquartile range (IQR)) NLR measured on admission to the hospital was 8.09 (4.90 ‐ 14.86), and the NLR ranged from 0.26 to 136.7. The admission NLR was statistically significantly higher in the high‐care group v. the general ward group (p<0.001). After converting the NLR to log scale, to bring it closer to conditional normality, logistic regression analysis identified log NLR (odds ratio (OR) 4.089; 95% confidence interval (CI) 2.464 ‐ 6.787; p<0.001) and age (OR 1.029; 95% CI 1.004 ‐ 1.056; p=0.024) as significant in determining who will require high care. The area under the receiver operating characteristic curve for the combined model of NLR and age was 0.829 (95% CI 0.767 ‐ 0.891). An NLR cut‐off value of 7.5 (sensitivity 0.7462, specificity 0.7968) has been calculated as the optimal cut‐off value to determine who will need high care. Admission log NLR and age were significant in determining who died (OR 2.067; 95% CI 1.404 ‐ 3.045; p<0.001, and OR 1.043; 95% CI 1.018 ‐ 1.068; p=0.001, respectively).
Conclusion. The NLR measured on admission and age can be used to predict whether a patient with COVID‐19 pneumonia will require high care.
References
Mendelson M, Booyens L, Boutall A, et al. The mechanics of setting up a COVID‐19 response: Experiences of the COVID‐19 epidemic from Groote Schuur Hospital, Cape Town, South Africa. S Afr Med J 2020;110(10):968‐972. https://doi.org/10.7196/SAMJ.2020.v110i10.15215
Simadibrata D, Calvin J, Wijaya A, Ibrahim N. Neutrophil‐to‐lymphocyte ratio on admission to predict the severity and mortality of COVID‐19 patients: A meta‐analysis. Am J Emerg Med 2021;42:60‐69. https://doi.org/10.1016/j.ajem.2021.01.006
Ciccullo A, Borghetti A, Zileri dal Verme L, et al. Neutrophil‐to‐lymphocyte ratio and clinical outcome in COVID‐19: A report from the Italian front line. Int J Antimicrob Agents 2020;56(2):106017. https:// doi.org/10.1016/j.ijantimicag.2020.106017
Zeng Z‐Y, Feng S‐D, Chen G‐P, Wu J‐N. Predictive value of the neutrophil to lymphocyte ratio for disease deterioration and serious adverse outcomes in patients with COVID‐19: A prospective cohort study. BMC Infect Dis 2021;21(1):80. https://doi.org/10.1186/s12879‐021‐05796‐3
Cheng B, Hu J, Zuo X, et al. Predictors of progression from moderate to severe coronavirus disease 2019: A retrospective cohort. Clin Microbiol Infect 2020;26(10):1400‐1405. https://doi.org/10.1016/j. cmi.2020.06.033
Kong M, Zhang H, Cao X, Mao X, Lu Z. Higher level of neutrophil‐to‐lymphocyte is associated with severe COVID‐19. Epidemiol Infect 2020;148:e139. https://doi.org/10.1017/S0950268820001557
Lian J, Jin C, Hao S, et al. High neutrophil‐to‐lymphocyte ratio associated with progression to critical illness in older patients with COVID‐19: A multicenter retrospective study. Aging 2020;12(14):13849‐ 13859. https://doi.org/10.18632/aging.103582
Gordon A, Breiman L, Friedman J, Olshen R, Stone C. Classification and regression trees. Biometrics 1984:40(3):874.
R Core Team. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria, 2021. https://www.R‐project.org/ (accessed 7 March 2022).
Alkhatip A, Kamel M, Hamza M, et al. The diagnostic and prognostic role of neutrophil‐to‐lymphocyte ratio in COVID‐19: A systematic review and meta‐analysis. Expert Rev Mol Diagn 2021;21(5):505‐514. https://doi.org/10.1080/14737159.2021.1915773
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