Predictive values of neutrophil-to-lymphocyte ratio on disease severity and mortality in COVID-19 patients: a systematic review and meta-analysis

Abstract

Background：Coronavirus disease 2019 (COVID-19), a highly infectious disease, has been rapidly spreading all over the world and posted a great threat to global public health. Patients diagnosed with severe or critical cases have a poor prognosis. Hence, it is crucial for us to identify potential severe or critical cases early, and give timely treatments for the targeted patients. In the clinical practice of treating COVID-19 patients, we have observed that the neutrophil-to-lymphocyte ratio (NLR) of severe patients is higher than that in mild patients. We performed this systematic review and meta-analysis to evaluate the predictive values of NLR on disease severity and mortality in COVID-19 patients. Methods: We searched PubMed, EMBASE, China National Knowledge Infrastructure (CNKI) and Wanfang databases to identify eligible studies (up to August 11, 2020). Two authors independently screened studies and extracted data. The methodological quality of the included studies was assessed by Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2).Results: Thirteen studies involving 1579 patients reported the predictive value of NLR on disease severity. The pooled sensitivity (SEN), specificity (SPE) and area under curve (AUC) were 0.78 (95% CI 0.70-0.84), 0.78 (95% CI 0.73-0.83) and 0.85 (95% CI 0.81-0.88), respectively. Ten studies involving 2967 patients reported the predictive value of NLR on mortality. The pooled SEN, SPE and AUC were 0.83 (95% CI 0.75-0.89), 0.83 (95% CI 0.74-0.89) and 0.90 (95% CI 0.87-0.92), respectively. Conclusions: NLR has good predictive values on disease severity and mortality in COVID-19 patients. Evaluating NLR can help clinicians identify potentially severe cases early, conduct early triage and initiate effective management in time, which may reduce the overall mortality of COVID-19. Moreover, we can better allocate scarce medical resources in this unprecedented time. Trial registration: This meta-analysis was prospectively registered on PROSPERO database (Registration number: CRD42020203612).

Comparison of neutrophil-lymphocyte ratio among severe acute respiratory illness COVID-19 positive and negative patients and to correlate with disease severity

“…12 A metanalysis done by Xiaoming et al to evaluate the predictive value of NL ratio suggested that NL ratio has good predictive in terms of severity and mortality in COVID-19 hence helping clinicians in predicting severity early and treating adequately. 13 In contrast to our study, Turk Thorac J et al showed that NL ratio was lower (average NL=5.89) in COVID-19 positive SARI and was higher (avg NL=11.41) in non-COVID-19 SARI. 9 Regarding the association with co-morbidities, our study found that NL ratio was significantly higher in severe COVID-19 patients with diabetes and hypertension.…”

Neutrophil‐to‐lymphocyte ratio is independently associated with COVID‐19 severity: An updated meta‐analysis based on adjusted effect estimates

“…However, the findings of Chan et al's 1 study were based on unadjusted effect estimates. Two other meta‐analyses on this topic also reported unadjusted effect estimates 2,3 . It was worth noting that a univariate analysis indicated that NLR was an important risk factor significantly associated with COVID‐19 severity.…”

Severity of COVID-19 Respiratory Complications during Pregnancy are Associated with Degree of Lymphopenia and Neutrophil to Lymphocyte Ratio on Presentation: A Multicenter Cohort Study

“…Several large studies of nonpregnant COVID-19 adults have shown that increased NLR has high degree of association with mortality and severe morbidity, with one study finding NLR to be the most important prognostic factor for severity. [6][7][8][9] This builds on prior evidence that the NLR is a highly sensitive predictor of prognosis in a wider spectrum of acute medical conditions such as brain infarct, cerebral hemorrhage, major cardiac events, and sepsis. [10][11][12][13] The studies investigating NLR in pregnant patients have been small.…”