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

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.

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.

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.

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.