Role of inflammatory biomarkers in the prediction of ICU admission and mortality in patients with COVID-19

Background: Inflammatory cytokines have been implicated in the pathophysiology and prognosis of severe COVID-19. Inflammatory biomarkers may guide the clinician in making treatment decisions as well as in the allocation of resources.  Objective: This study aimed to assess how levels of inflammatory biomarkers predict disease severity and mortality in patients with COVID-19 by testing a predictive scoring model developed by Zhou et al and further refining the model in a population of patients hospitalized with COVID-19.   Study Design and Methods: This retrospective study included patients with COVID-19 admitted to ten Virginia hospitals from January 1, 2020, to June 15, 2020. Inflammatory markers including CRP, D-Dimer, ferritin, N/L ratio, and procalcitonin were studied and logistic regression models were applied to ascertain the risk of ICU admission and mortality with elevated markers.  Results: Data from a total of 701 patients were analyzed. In bivariate tests age, CRP, D-Dimer, and N/L ratio were associated with in-hospital mortality as well as admission to the ICU.  Procalcitonin was associated with admission to the ICU but not mortality. Males and African Americans were more likely to require ICU-level care. In final models, age and CRP were significantly associated with mortality (OR 1.06, 95% CI 1.04-1.08, and OR 1.06, 95% CI 1.03-1.10 respectively) as well as ICU admissions (OR 1.02, 95% CI 1.01-1.03 and OR 1.03, 95% CI 1.01-1.06 respectively). The previously established composite scores of CRP, D-Dimer, and N/L ratio were predictive of mortality (Area under the curve [AUC] 0.69 for multiplicative score) as well as ICU admissions (AUC 0.61 for multiplicative score). However, improved accuracy was obtained with age and CRP for predicting mortality (AUC 0.77) and ICU admission (AUC 0.62). Conclusions: CRP and age appear to be the strongest predictors for ICU admission and mortality compared to D-Dimer, Ferritin, Procalcitonin, and N/L ratio in patients with COVID-19.