ALB and nutritional deficiency disease: Although our findings are mainly consistent with previous research reports, several new discoveries have emerged: (1) serum GDF15 is an independent risk factor for AECOPD patients with comorbid malnutrition; (2) serum GDF15 levels hold promise as a predictive biomarker for identifying malnutrition during AECOPD episodes, with the combination of serum ALB levels having a higher predictive ability for malnutrition in patients with AECOPD.