ALB and chronic obstructive pulmonary disease: In addition, the readmission group was significantly more likely to be obese (25.5% vs. 13.7%), classified as ASA III-IV (21.3% vs. 11.3%), have heart disease (19.1% vs. 7.1%), have a CCI ≥4 (12.8% vs. 3.5%), present with anemia at admission (57.4% vs. 40.0%), and showed a tendency toward a higher prevalence of COPD (12.8% vs. 5.7%), albumin < 35 g/L (50.0% vs. 28.1%), and lower sodium ion concentration (23.4% vs. 13.2%) (Table 1).