Fig. 1.

(A) The ROC curves for CRP, WBC, and L to assess disease classification and for CEA to assess disease progression. The AUC values for CRP, WBC, L, and L% were 0.724(0.625–0.823), 0.768(0.676–0.861), 0.743(0.647–0.839), and 0.8186(0.728–0.910), respectively, while the critical values were 156.8 mg/L, 17.44 × 10⁹/L, 0.545 × 10⁹/L, and 5.95%, respectively. The ROC curves 1–2 for CEA were analyzed to predict the progression of COVID-19. “1” is the ROC curve for CEA for disease progression from moderate to severe type, while “2” is the curve for disease progression from moderate to critically severe type. The AUC values of these curves were 0.578(0.442–0.715) and 0.741(0.644–0.839), respectively. (B) Survival curves of patients with different initial levels of CEA, WBC, L, and CRP. COVID-19 patients with initial CEA levels of over 7.75 or 29.75 ng/mL had worse outcomes than patients with lower CEA levels. Patients with L counts and L% less than 0.545 G/L and 5.95% had worse outcomes than the patients with higher L counts and L%, respectively. There was no significant difference in outcome between patients with CRP levels of over 156.5 ng/mL and patients with lower CRP levels. (C) Construction of nomogram with CEA and other significant indicators that predicted the probability of COVID-19 patients for overall survival. For using the nomogram, the value of individual patients with COVID-19 is located on each variable axis, and a line is depicted upward to determine the number of points received for each variable value. The sum of these numbers is located on the Total Point axis, and a line is drawn downward to the survival axes to predict the likelihood of 1-, 2-month survival of OS.