Abstract: Objective To investigate the relationship of serum iron-regulated protein 2 (IRP2) and decoy receptor 3 (DcR3) levels with disease outcome in elderly patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). 
Methods In total, 88 patients with AECOPD (AECOPD group) were selected, and serum IRP2 and DcR3 levels of subjects were detected. Clinical disease outcomes of AECOPD patients were tracked and they were divided into aggravation group (n=22) and improvement group (n=66) according to clinical disease outcomes. Multivariate Logistic regression analysis was used to analyze the factors influencing disease outcome of AECOPD patients. The value of IRP2 and DcR3 in predicting the outcome of AECOPD patients was analyzed by receiver operating characteristic curve (ROC). 
Results The number of AECOPD attacks, acute physiological and chronic health status scores, combined shock and dyspnea scores, and modified medical research council (mMRC) grades 3-4 in the aggravation group were better than those in the improvement group (P＜0.05). The serum IRP2 and DcR3 levels in the aggravation group were higher than those in the improvement group before and at 2 weeks after treatment, and the serum IRP2 and DcR3 levels in the improvement group at 2 weeks after treatment were lower than those before treatment (P＜0.05). There was no significant difference in serum IRP2 and DcR3 levels in the aggravation group compared with those before treatment (P＞0.05). Multivariate Logistic regression analysis showed that the number of AECOPD attacks within 1 year, mMRC grade, IRP2 before treatment, DcR3 before treatment were risk factors for disease deterioration in patients with AECOPD (P＜0.05). The area under the ROC curve (AUC) of IRP2 and DcR3 before treatment in predicting disease outcome of AECOPD patients was 0.781 and 0.795 respectively, and the AUC of IRP2 and DcR3 in combination was 0.918, which was greater than that predicted by IRP2 and DcR3 alone (P＜0.05). 
Conclusion Serum levels of IRP2 and DcR3 are significantly increased in AECOPD patients, and are associated with decreased lung function and disease deterioration. Detection of serum levels of IRP2 and DcR3 is helpful to predict the disease outcome in AECOPD patients. 

Key words: pulmonary disease, chronic obstructive, iron regulatory protein 2, decoy receptor 3