Neutrophil-to-Lymphocyte and Platelet-to-Lymphocyte Ratios in COVID-19 Patients and Control Group and Relationship with Disease Prognosis

Background: The present study aimed to compare the complete blood count (CBC) indices between COVID-19 patients and the control group, and assess the relationship of these indices with COVID-19 prognosis given the role of complete blood counts in the COVID-19 prognosis. Methods: COVID-19 patients (confirmed by PCR or CT-Scan) who visited Imam Hospital in Sari were selected in this case-control study. The control group was selected from Tabari cohort population who were matched with the case group in terms of gender and age. CBC, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and outcome of the disease (in the case group) were assessed in this study. Results: The number of participants in the case and control groups was 527. Of these, 464 (44%) were females. Platelet count, lymphocyte count, and hemoglobin concentration were also higher in the control group (p = 0.000). NLR and PLR were significantly higher in COVID-19 patients compared to the control group (P = 0.000). NLR had a significant relationship with severity of the disease. NLR was two times higher in the patients who died of COVID-19 than those who recovered (P = 0.000). ROC curve analysis for diagnostic values of NLR and PLR showed that the areas under the ROC curves for NLR and PLR were 0.703 (95% CI: 0.64-0.76) and 0.535 (95% CI: 0.46-06) respectively. Conclusion: NLR can be used as a prognostic marker for COVID-19 given the significant difference of NLR between those died and recovered from COVID-19.