Evaluation of individual and combined NLR, LMR and CLR ratio for prognosis disease severity and outcomes in patients with COVID-19

OBJECT: The study aimed to utilize the peripheral blood immunological parameters and resulting individual and combined inflammatory indices [neutrophil/lymphocyte ratio (NLR), lymphocyte/monocyte ratio (LMR) and C-reactive protein/lymphocyte ratio (CLR)] in predicting the prognosis and mortality in COVID-19 patients. MATERIALS AND METHODS: The measurements of individual and combined inflammatory indices (NLR, LMR and CLR) were performed at hospital admission and at last day of hospitalization for COVID-19 patients. RESULTS: Prominent elevation of NLR and CLR among patients with refractory disease admitted to Intensive Care Unit (ICU) and deceased patients was found when compared with moderate ill patients and healthy controls. Interestingly, NLR and CLR typically returned to near normal value as patients recover from severe infection. By contrast, deceased patients had persistent increased NLR and CLR until last day of hospitalization in ICU. ROC obtained for the above parameters showed that NLR and CLR were the most associated immunological parameters with the severity of COVID-19 disease. Using multivariate logistic regression analysis, CLR > 69.46 is an independent prognostic factors in identifying critically ill COVID-19 cases. Study of the combined markers NLR and CLR showed that most of patients admitted in ICU were characterized with high NLR combined with high CLR, while most of healthy subjects and non-ICU group have low NLR combined with low CLR. CONCLUSION: The combination of NLR and CLR could improve the predictive efficacy compared to individual markers to segregate patients who will develop a severe disease from those with a mild pathology.