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

Introduction: 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.

Purpose: 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.

Methods: 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.

Results: TLC, ANC, AMC, NLR, d-NLR and, PLR were highest in the critical group (<0.001 for all except AMC =0.033), while this group had the least ALC and LMR (=0.049 and <0.001, respectively). Higher CRP and d-dimer levels were reported in the critical group (<0.001). At the same time, higher ferritin was found in the severe group more than the critical and non-severe groups (<0.001, =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.

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