Preliminary study to identify severe from moderate cases of COVID-19 using NLR&RDW-SD combination parameter

changzheng wang; Chengbin Li

The copyright holder for this preprint . https://doi.org/10.1101/2020.04.09.20058594 doi: medRxiv preprint lymphopenia reached 82.1% [27] . There was no significant difference in platelet count between the moderate and severe patients (P> 0.05). When the SARS broke out in 2003 in Guangzhou, China, it was first reported that the while blood cells count was normal or decreased (80.2%), the lymphocytes and eosinophils decreased, monocytes increased and thrombocytes decreased in some patients [22] . Similarly, a report from Hong Kong indicated that of 157 patients 153 (98%) had lymphopenia, 87 (55%) had thrombocytopenia, 77 (49%) had thrombocytosis, and 95 (61%) had hemoglobin decreased more than 20 g/L. The autopsy showed a decrease in lymphocytes in haemato-lymphoid organs, and multivariate analysis showed that old age and high concentration of LDH were independent predictors of poor prognosis. Lymphopenia and T lymphocyte subpopulation depletion may be related to the disease [23] . The results of our study are similar to the reported above [3, 26 and 27] . Lymphocytes and platelets are also important indicators for monitoring the peak viral load and immunopathological damage in the palliative treatment of lung disease with Abidol combined with lopinavir and ritonavir [24] . In this study, both the ratio of neutrophils to lymphocytes (NLR) and the ratio of platelets to lymphocytes (PLR) in the severe group showed significantly higher (P <0.05), and showed the best single parameter differential diagnostic efficacy (NLR AUC = 0.890, PLR AUC = 0.842). Liu et al [3] from Beijing Ditan Hospital Capital Medical University (Beijing, China) also suggested that NLR was helpful for early detection of severe COVID-19 patients nad had a high prediction accuracy (AUC = 0.849), which is consistent with the conclusion of this article. In addition, this study found that the red blood cell parameters (RBC, HGB, HCT) were significantly reduced in the severe group, while the morphological parameters (RDW-CV, RDW-SD) were significantly higher in the severe group than moderate patients, which may result from the immune damage that leads to the suppression of the bone marrow, leading to the gradual increase of anemia that causes the compensatory hyperplasia of erythroid cell line, a large number of immature red blood cells released to the peripheral blood, the activation of red blood cell apoptosis and peripheral phagocytosis, therefore result in the increase of the red blood cell distribution width [31] . In the comparison of the significantly lower than that in the moderate group (P <0.05), which is also consistent with recent reports by most scholars [11, 16, [26] [27] [28] .