Clinical Value of Inflammatory Biomarkers in Determining Severity of COVID-19

Background: COVID-19 infection can occur as a mild, moderate, or severe illness. How patients will be more serious has not been fully revealed so far. To investigate the role of systemic inflammation index (SII), platelet-to-lymphocyte ratio (PLR), mean platelet volume (MPV), mean platelet volume to platelet ratio (MPR), and neutrophil-to-lymphocyte and platelet ratio (NLPR) in determining the severity of COVID-19 patients. Methods: We retrospectively studied 397 patients with confirmed COVID-19 who were admitted to the emergency departments (EDs) between January and June 2020. According to the criteria recommended by World Health Organization, patients were divided into two groups as severe and non-severe cases. Demographic, clinical characteristics, and inflammation parameters of patients were evaluated. Results: The NLPR, SII, MPR, and PLR were significantly increased in severe COVID-19 patients compared to the non-severe patients (p < 0.0001, p = 0.0002, p = 0.0441 , p = 0.0469, respectively). On the other hand, the MPV value did not show a statistically significant difference between cases. In ROC analysis calculated for inflammatory biomarkers in the prediction of COVID-19 severity, NLPR exhibited the largest area under the curve (AUC) at 0.705, with the highest specificity (81.45%) and sensitivity (56.25%) at the optimal cut-off of 0.024 (p < 0.0001). SII (AUC: 0.670) was the second inflammatory parameter with high specificity (63.21%) and sensitivity (66.67%) following NLPR value (p = 0.0002). Conclusion: NLPR and SII may be new inflammatory markers to identify severe COVID-19 patients at the time of admission to the ED.