Use of Neutrophil-to-Lymphocyte and Platelet-to-Lymphocyte Ratios in COVID-19

Abstract

Background: As the pandemic of coronavirus disease 2019 (COV-ID-19) continues, prognostic markers are now being identified. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are easily accessible values that have been known to correlate with inflammation and prognosis in several conditions. We used the available data to identify the association of NLR and PLR with the severity of COVID-19. Methods: A literature search using EMBASE, MEDLINE, and Google Scholar for studies reporting the use of NLR and PLR in COVID-19 published until April 28, 2020, was performed. Random effects meta-analysis was done to estimate standard mean difference (SMD) of NLR and PLR values with 95% confidence interval (CI) between severe and non-severe COVID-19 cases. Results: A total of 20 studies with 3,508 patients were included. Nineteen studies reported NLR values, while five studies reported PLR values between severe and non-severe COVID-19 patients. Higher levels of NLR (SMD: 2.80, 95% CI: 2.12-3.48, P < 0.00001) and PLR (SMD: 1.82, 95% CI: 1.03-2.61, P < 0.00001)) were seen in patients with severe disease compared to non-severe disease. Conclusions: NLR and PLR can be used as independent prognostic markers of disease severity in COVID-19.

Comparison of Clinical, Para-clinical and Laboratory Findings in Survived and Deceased Patients with COVID-19: Diagnostic Role of Inflammatory Indications in Determining the Severity of Illness

“…Furthermore, in another study, a correlation between elevated PLR and the length of hospitalization day was evidenced and it has been concluded that if PLR increased more during treatment, the patient needs longer hospitalization day and had greater possibility of severe pneumonia [25]. Furthermore, Chan et al in a meta-analysis concluded that NLR and PLR can be served as independent prognostic markers of disease severity in COVID-19 [26]. Recently, NLR and PLR have been validated as prognostic factors in various disorders such as cardiac conditions, solid tumors, sepsis, pneumonia, and ARDS [26].…”

“…Furthermore, Chan et al in a meta-analysis concluded that NLR and PLR can be served as independent prognostic markers of disease severity in COVID-19 [26]. Recently, NLR and PLR have been validated as prognostic factors in various disorders such as cardiac conditions, solid tumors, sepsis, pneumonia, and ARDS [26]. The SII has been proposed as a prognostic indicator in the follow-up of sepsis patients (Systemic immune in ammatory index in sepsis).…”

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

“…Therefore, NLR, a cost-effective marker can be easily calculated from peripheral blood routine tests, and may be associated with the progression and prognosis of COVID-19. There were few meta-analyses pointing out patients with severe COVID-19 had a higher NLR than those with non-severe COVID-19 [51][52][53][54]. However, none of them evaluated the predictive values of NLR on disease severity and mortality.…”

Comparison of clinical, para-clinical and laboratory findings in survived and deceased patients with COVID-19: diagnostic role of inflammatory indications in determining the severity of illness

“…In another study, a correlation between elevated PLR and the length of hospitalization day was evidenced and it has been concluded that if PLR increased more during treatment, the patient needs longer hospitalization day and had greater possibility of severe pneumonia [ 25 ]. Furthermore, Chan et al in a meta-analysis concluded that NLR and PLR can be served as independent prognostic markers of disease severity in COVID-19 [ 26 ]. Recently, NLR and PLR have been validated as prognostic factors in various disorders such as cardiac conditions, solid tumors, sepsis, pneumonia, and ARDS [ 26 ].…”