Routine hematology parameters in COVID-19: A predictor of disease severity and mortality

Our understanding of the pathophysiology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is still evolving and is limited for prognostication. The study was performed to predict severity and mortality based on hematology parameters in coronavirus disease (COVID-19).

The study was a single-center retrospective analysis of 240 patients with COVID-19. The hematological parameters were compared between different grades of severity. The receiver operating characteristics (ROC) curve along with the Classification and Regression Trees (CART) methods were used for the analysis.

The total leukocyte count, absolute neutrophil count, neutrophil-lymphocyte ratio (NLR), and neutrophil-monocyte ratio (NMR) were increasing along with an increase in severity; while the absolute lymphocyte count and lymphocyte-monocyte ratio (LMR) were decreasing (P < 0.001). For prediction of severity and mortality on admission, the NLR, NMR, and LMR were significant (P < 0.001). The NLR, NMR, and LMR had an area under the receiver operating characteristics curve (AUROC) of 0.86 (95% CI of 0.80-0.91), 0.822 (95% CI of 0.76-0.88), and 0.69 (95% CI of 0.60-0.79), respectively, for severity. While the NLR, NMR, and LMR had an AUROC value of 0.85 (95% CI of 0.79-0.92), 0.83 (95% CI of 0.77-0.89), and 0.67 (95% CI of 0.57-0.78), respectively, for mortality.

With the increase in severity there was an increase in the total leukocyte count and absolute neutrophil count while the absolute lymphocyte count decreased. On admission, the cut-off value of NLR >5.2, NMR >12.1, while LMR <2.4 may predict severity and mortality in COVID-19.