The Impact of Neutrophil-Lymphocyte Count Ratio in COVID-19: A Systematic Review and Meta-Analysis

Abstract

Background: The neutrophil–lymphocyte count ratio (NLR) has emerged as a potential prognostic tool for different diseases. In the current coronavirus disease (COVID-19) pandemic, the NLR may be a useful tool for risk scarification and the optimal utilization of limited healthcare resources. However, there is no consensus regarding the optimal value of NLR, and the association with disease severity and mortality. Thus, this study aims to systematically analyze the current evidence of the utility of baseline NLR as a predictive tool for mortality, disease severity in COVID-19 patients. Methods: A compendious screening of electronic databases up to June 15, 2021, was done after enlisting the protocol in PROSPERO (CRD42020202659). Studies evaluating the utility of baseline NLR in COVID-19 are included for this review as per the PRISMA statement. Results: We retrieved a total of 13112 and 12986 COVID-19 patients for survivability and severity over 90 studies. The expired and critically sick patients had elevated baseline NLR on admission, in comparison to survivors and noncritical patients. (SMD = 3.82; 95% CI: 2.79-4.85; I2 = 100% and SMD = 1.42; 95% CI: 1.22-1.63; I2 = 95%, respectively). The summary receiver operating curve analysis for mortality (AUC = 0.87; 95% CI: 0.86-0.87; I2 = 94.7%), and severity (AUC = 0.82; 95% CI: 0.80-0.84; I2 = 79.7%) were also suggestive of its significant predictive value. Conclusions: The elevated NLR on admission in COVID-19 patients is associated with poor outcomes.

Prognostic factors for the severe course of COVID-19 in the different COVID-19 peak periods in Central Kazakhs

“…We found that in 2020-year patients' age, gender, presence of CKD, COPD, fever, increase in NLR, and decrease in oxygen saturation had significant predictive value for COVID-19 severity. The data obtained are consistent with numerous results of other works were shown the predictive value of age [16], gender [17], comorbidity [18][19][20], clinical symptoms of disease [21], and increase of NLR [22] for the prognosis of severity and death.…”

Case report: COVID-19 infection in a pregnant 33-year-old kidney transplant recipient

“…Meta-analyzes also shows that the NLR can be a good marker of disease severity and has predictive value for the outcome. The limit cannot be clearly established, but a severe case above 4.5 seems to be expected ( 16 , 17 ). Elmaradny and colleagues studied the relationship between NLR and preeclampsia.…”

High neutrophil‐to‐lymphocyte ratio at intensive care unit admission is associated with nutrition risk in patients with COVID‐19

“…In addition, elevated NLR values on hospital admission are linked to mortality and severity of COVID‐19. 44 , 45 …”

“…In agreement with our findings, a previous review and meta‐analysis highlighted the NLR as an imperative marker of prognosis for patients with COVID‐19. In addition, elevated NLR values on hospital admission are linked to mortality and severity of COVID‐19 44,45 …”

“…In addition, elevated NLR values on hospital admission are linked to mortality and severity of COVID-19. 44,45 Although the modified form of the NUTRIC score, which excludes IL-6, has been validated, several studies seek to simplify it by replacing IL-6 with more-available variables, such as CRP. 14,46 The measurement of IL-6 concentrations is not common during the hospital clinical practice, which makes the NUTRIC tool difficult to use in its original form.…”