Evaluation of the Predictive value of C-reactive Protein, Interleukin-6 and their derived immune-inflammatory indices in COVID-19 Egyptian patients

Background: In coronavirus disease 2019 (COVID-19), finding sensitive biomarkers is critical for detecting severe cases early and intervening effectively. Aim of the work:  To compare and evaluate the value of pretreatment c-reactive protein (CRP), interleukin-6 (IL-6), and their derived immune-inflammatory indices (CRP/albumin (CRP/alb), lymphocyte/CRP (L/CRP), and lymphocyte/IL-6 (L/IL-6)) in the prediction of COVID-19 severity and in-hospital mortality. Methods: This cross-sectional study included 85 confirmed COVID-19 patients, their complete blood count with differential, as well as albumin and IL-6 levels on the day of their hospital admission, were assessed and compared. We followed all patients till their in-hospital death or discharge from the hospital. Results: On admission levels of CRP, IL-6, and CRP/alb were significantly higher (p < /em>=0.001) in severe patients and non-survivors, but L/CRP and L/IL-6 were significantly lower (p < /em>=0.001) compared to non-severe patients and non-survivors. CRP/alb and L/CRP at cut-offs of 1.65 and 260.86, respectively, were the best predictors for COVID-19 severity, while IL-6 and L/IL-6 at cut-offs of 120 pg/ml and 5.40, respectively, were the best predictors for COVID-19 in-hospital mortality. IL-6 was an independent risk factor associated with severe disease development (odds ratio (OR): 1.033; 95% confidence interval (CI): 1.002-1.066). Conclusions: Pretreatment levels of CRP, IL-6, and their derived indices should be included in the diagnostic work-up of COVID-19 to determine the severity and predict the outcome