ALB and intestinal obstruction: For risk score system, stratification of age, albumin, and exclusion of culture-negative, intestinal obstruction did not change the prediction model performances, the discrimination ranged from 0.74 to 0.80, and all P-values of Hosmer-Lemeshow statistic were >0.05 (Supplementary Table 3), indicating the good robustness of the risk score system.