Can Hematological Ratios Predict Outcome of COVID-19 Patients? A Multicentric Study

Coronaviruses belong to a large family that leads to respiratory infection of various severity. Hematological ratios are indicators of inflammatory response widely used in viral pneumonia with affordability in developing countries.

Study the role of the neutrophil lymphocyte ratio (NLR), derived NLR ratio (d-NLR), platelet lymphocyte ratio (PLR), and lymphocyte monocyte ratio (LMR) in predicting the outcome of COVID-19 Egyptian patients.

A retrospective study on 496 COVID-19 Egyptian patients, managed in four tertiary centers, grouped into non-severe, severe, and critical. Patients' laboratory assessment including total leucocyte count (TLC), absolute neutrophil count (ANC), absolute lymphocyte count (ALC), absolute monocyte count (AMC), NLR, d-NLR, LMR and, PLR were reported as well as C reactive protein (CRP), D-dimer and serum ferritin.

TLC, ANC, AMC, NLR, d-NLR and, PLR were highest in the critical group (p<0.001 for all except AMC p=0.033), while this group had the least ALC and LMR (p=0.049 and <0.001, respectively). Higher CRP and d-dimer levels were reported in the critical group (p<0.001). At the same time, higher ferritin was found in the severe group more than the critical and non-severe groups (p<0.001, p=0.005, respectively). We calculated the optimal cut-off values of the hematological ratio; NLR (3.5), d-NLR (2.86), PLR (192), and LMR (3). D-NLR had the highest specificity (89.19%), while NLR had the highest sensitivity (71.38%). By univariate logistic regression, age, DM, HTN, cardiovascular diseases, COPD, NLR, d-NLR, LMR and PLR, CRP, steroid, oxygen aids, and mechanical ventilation were associated with the severity of COVID-19. Still, only age, NLR, CRP, and oxygen aid were independent predictors in multivariate logistic regression.

NLR is a predictor for severity in COVID-19. LMR, d-NLR, and PLR may assist in risk stratification.