Differences of inflammatory and non-inflammatory indicators in Coronavirus disease-19 (COVID-19) with different severity

Background A variety of inflammatory and non-inflammatory indicators were increased in severe and critical Coronavirus disease-19 (COVID-19) and some of them were used to evaluate the severity and predict prognosis of community-acquired pneumonia. The aim of this study was to investigate the association of these indicators in COVID-19 with different severity. Methods Clinical data of 46 patients with severe COVID-19 and 31 patients with critical COVID-19 were collected. The general characteristics and comorbidities of the patients were retrospectively analyzed. The initial and peak concentrations of serum troponin I (cTnI), D-dimer (D-D), C-reactive protein (CRP), interleukin-6 (IL-6), procalcitonin (PCT), initial and peak neutrophil counts and initial and trough lymphocyte counts were compared between two groups. The correlation between the variation of cTnI, D-D, CRP, IL-6, PCT, neutrophils, lymphocytes and the severity of the disease was analyzed. The efficacy of the initial concentrations of cTnI, D-D, CRP, IL-6, PCT, the initial neutrophil and lymphocyte counts in predicting critical COVID-19 were evaluated by receiver operating characteristic (ROC) curve. Results The initial and peak concentrations of cTnI, D-D, CRP, IL-6, PCT, initial and peak neutrophil counts in critical group were higher than those in severe group, the initial and trough counts of lymphocyte were lower than those in the severe group. Except for the initial level of PCT, the other differences were statistically significant (p < 0.05). The increase of cTnI, D-D, CRP, IL-6, PCT, neutrophils and the decrease of lymphocytes were related to the severity of the disease, OR values were 28.80, 2.20, 18.47, 10.80, 52.00, 9.60 and 21.08, respectively. Except for D-D, the other differences were statistically significant. The areas under ROC curves for predicting critical COVID-19 by initial concentrations of cTnI, D-D, CRP, IL-6, PCT, initial lymphocyte and neutrophil counts were 0.76, 0.78, 0.83, 0.95, 0.56, 0.68 and 0.62, respectively. Conclusions The severe and critical COVID-19 patients had significant differences in concentrations of serum cTnI, D-D, CRP, IL-6, PCT, neutrophil and lymphocyte counts. The increase of cTnI, CRP, IL-6, PCT, neutrophils and decrease of lymphocytes indicated severe condition. The initial IL-6 might be a good indicator of COVID-19 severity.